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BACKGROUND: Although arterial stiffness is known as a biomarker for cardiovascular events and stroke, there is limited information in the literature regarding the stiffness of intracranial aneurysms. In this study, we aim to assess the stiffness of intracranial aneurysms using 4D Flow MRI. METHODS: A total of 27 aneurysms in 25 patients with internal carotid artery aneurysms were included in this study. Using 4D Flow MRI, we measured the arterial pulse wave form during a cardiac cycle at planes proximal and distal to the target aneurysm. The damping of these waveforms through the aneurysm was defined as the aneurysm damping index (ADI) and compared to the contralateral side. We also investigated the clinical factors related to the ADI. RESULTS: ADI assessment was successful in all cases. The average ADI was 1.18±0.28, which was significantly larger than 1.0 (P = 0.0027 [t-test]). The ADI on the aneurysm side was larger than on the contralateral side (1.19±0.30 vs 1.05±0.17, P = 0.029 [t-test]). On multivariate analysis, the use of beta-blockers (β=0.46, P = 0.015) and smoking history (β=-0.22, P = 0.024) showed a significant correlation with ADI. CONCLUSION: We have proposed a novel method to observe arterial pulse wave dumping through intracranial aneurysm using 4D Flow MRI. The damping can be quantitatively observed, and the ADI has correlations with clinical factors such as antihypertensive drugs and smoking. Further studies should focus more on evaluating aneurysm stiffness and its clinical applications.

DOI： 10.1101/2024.04.05.24302112

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BACKGROUND: This study aimed to investigate the preoperative risk factors for prolonged operating time in retroperitoneoscopic radical nephrectomy (RRN) for renal cell carcinoma (RCC). METHODS: We retrospectively reviewed patients treated for RRN between January 2015 and December 2021. Clinical data, including radiological findings such as visceral fat area (VFA), subcutaneous fat area (SFA), and posterior perirenal fat thickness (PFT) were collected. The operating time for RRN was analyzed using univariate and multivariate logistic regression analyses. RESULTS: A total of 79 patients were included. The median age was 66 (range: 28-88) years and 48 (60.8%) had right-sided tumors. The median tumor size was 52 (range: 12-100) mm. Median BMI, VFA, SFA, and posterior PFT were 22.9 (range: 16.3-42.2) kg/m2, 102 (range: 14-290) cm2, 124 (range: 33-530) cm2, and 6 (range: 1-35) mm. The median operating time was 248 (range: 140-458) min. Univariate logistic regression analyses revealed that a right tumor (p=0.046), tumor size >7 cm (p=0.010), and posterior PFT >25 mm (p=0.006) were preoperative risk factors for prolonged operating time in RRN. Multivariate logistic regression analyses revealed that a posterior PFT of >25 mm was an independent preoperative risk factor for prolonged operating time for RRN (p=0.008, OR: 7.29, 95% CI: 1.69-31.5). CONCLUSIONS: A posterior PFT >25 mm was an independent preoperative risk factor for the operating time of RRN. In RRN, for patients with a posterior PFT >25 mm, surgeons should develop surgical strategies, including the selection of a transperitoneal approach to surgery, to avoid prolonging the operating time.

DOI： 10.1272/jnms.JNMS.2024_91-407

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OBJECTIVES: To investigate the usefulness of harmonized 18F-FDG-PET/CT parameters for predicting the postoperative recurrence and prognosis of oral tongue squamous cell carcinoma (OTSCC). METHODS: We retrospectively analyzed the cases of 107 OTSCC patients who underwent surgical resection at four institutions in Japan in 2010-2016 and evaluated the harmonized PET parameters of the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for the primary tumor as the pSUVmax, pMTV, and pTLG. For lymph node metastasis, we used harmonized PET parameters of nodal-SUVmax, nodal-total MTV (tMTV), and nodal-total TLG (tTLG). The associations between the harmonized PET parameters and the patients' relapse-free survival (RFS) and overall survival (OS) were evaluated by the Kaplan-Meier method and Cox proportional hazard regression analysis for model 1 (preoperative stage) and model 2 (preoperative   +  postoperative stages). RESULTS: The harmonized SUVmax values were significantly lower than those before harmonization (p=0.012). The pSUVmax was revealed as a significant preoperative risk factor for RFS and OS. Nodal-SUVmax, nodal-tMTV, and nodal-tTLG were significant preoperative risk factors for OS. The combination of pSUVmax + nodal-SUVmax significantly stratified the patients into a low-risk group (pSUVmax <3.97 + nodal-SUVmax <2.85 or ≥2.85) and a high-risk group (pSUVmax ≥3.97 + nodal-SUVmax <2.85 or pSUVmax ≥3.97 + nodal-SUVmax ≥2.85) for recurrence and prognosis (RFS: p=0.001; OS: p<0.001). CONCLUSIONS: The harmonized pSUVmax is a significant prognostic factor for the survival of OTSCC patients. The combination of pSUVmax and nodal-SUVmax identified OTSCC patients at high risk for recurrence and poor prognosis at the preoperative stage.

DOI： 10.1259/dmfr.20230083

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OBJECTIVES: Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer. METHODS: We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. RESULTS: Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. CONCLUSIONS: The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

DOI： 10.1016/j.xjon.2023.02.004

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BACKGROUND: The effect of posterior cranial fossa stroke on changes in cerebral volume is not known. We assessed cerebral volume changes in patients with acute posterior fossa stroke using CT scans, and looked for risk factors for cerebral atrophy. METHODS: Patients with cerebellar or brainstem hemorrhage/infarction admitted to the ICU, and who underwent at least two subsequent inpatient head CT scans during hospitalization were included (n = 60). The cerebral volume was estimated using an automatic segmentation method. Patients with cerebral volume reduction > 0% from the first to the last scan were defined as the "cerebral atrophy group (n = 47)," and those with ≤ 0% were defined as the "no cerebral atrophy group (n = 13)." RESULTS: The cerebral atrophy group showed a significant decrease in cerebral volume (first CT scan: 0.974 ± 0.109 L vs. last CT scan: 0.927 ± 0.104 L, P < 0.001). The mean percentage change in cerebral volume between CT scans in the cerebral atrophy group was -4.7%, equivalent to a cerebral volume of 46.8 cm3, over a median of 17 days. The proportions of cases with a history of hypertension, diabetes mellitus, and median time on mechanical ventilation were significantly higher in the cerebral atrophy group than in the no cerebral atrophy group. CONCLUSIONS: Many ICU patients with posterior cranial fossa stroke showed signs of cerebral atrophy. Those with rapidly progressive cerebral atrophy were more likely to have a history of hypertension or diabetes mellitus and required prolonged ventilation.

DOI： 10.1007/s00701-023-05609-3

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BACKGROUND: Radiographic detection of the Adamkiewicz artery (AKA) before aortic surgery helps to avoid spinal cord ischemia (SCI). We applied magnetic resonance angiography (MRA) using gadolinium enhancement (Gd-MRA) by means of the slow-infusion method with sequential k-space filling and compared AKA detectability with that of computed tomography angiography (CTA). METHODS: A total of 63 patients with thoracic or thoracoabdominal aortic disease (30 with aortic dissection [AD] and 33 with aortic aneurysm) who underwent both CTA and Gd-MRA to detect AKA were evaluated. The detectability of the AKA using Gd-MRA and CTA were compared among all patients and subgroups based on anatomical features. RESULTS: The detection rates of the AKAs using Gd-MRA and CTA were higher in all 63 patients (92.1% vs. 71.4%, P = 0.003). In AD cases, the detection rates using Gd-MRA and CTA were higher in all 30 patients (93.3% vs. 66.7%, P = 0.01) as well as in 7 patients whose AKA originated from false lumens (100% vs. 0%). In aneurysm cases, the detection rates using Gd-MRA and CTA were higher in 22 patients whose AKA originated from the nonaneurysmal parts (100% vs. 81.8%, P = 0.03). In clinical, SCI was observed in 1.8% of cases after open or endovascular repair. CONCLUSIONS: Despite the longer examination time and more complicated imaging techniques compared to those of CTA, the high spatial resolution of slow-infusion MRA may be preferable for detecting AKA before performing various thoracic and thoracoabdominal aortic surgeries.

DOI： 10.1016/j.avsg.2023.02.027

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Perineural spread (PNS) from pelvic carcinoma has been regarded as a pathway to muscle and bone metastasis. However, few cases have been reported, especially in patients with bladder carcinoma. In the present report, we discuss a case of diffuse cancer involvement in the muscle 5 years after radical cystectomy for advanced bladder carcinoma. Careful observation of temporal changes on medical images confirmed PNS as the pathway to muscle metastasis (i.e., primary PNS). Our report presents early and post-treatment CT, MRI and FDG-PET/CT findings of PNS from the bladder carcinoma.

DOI： 10.1272/jnms.JNMS.2024_91-301

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PURPOSE: The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). METHODS: From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. RESULTS: TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). CONCLUSION: TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.

DOI： 10.2463/mrms.mp.2022-0051

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INTRODUCTION: Most lipomas are readily dissected and removed. However, some cases can pose surgical difficulties. This retrospective study sought to identify clinical and radiological risk factors that predict difficult lipoma resection and can be used in a clinically useful scoring system that predicts difficulty preoperatively. METHODS: The study cohort consisted of all consecutive patients who underwent resection of pathology-confirmed lipoma during 2016-2018 at a tertiary care referral center in Tokyo, Japan. Surgical difficulty was defined as difficulty separating some/all of the tumor from the surrounding tissue by hand and inability to extract the tumor in one piece. Descriptive, univariate, and multivariate logistic regression analyses were conducted to identify predictive factors. The predictive accuracy of the scoring system that included these factors was assessed by tenfold cross-validation analysis. Receiver-operating curve (ROC) analysis was conducted to identify the optimal cutoff score for predicting surgical difficulty. RESULTS: Of the 86 cases, 36% involved surgical difficulty. Multivariate analysis showed that subfascial intramuscular location (odds ratio 42.7, 95% confidence interval 3.0-608.0), broad touching of underlying structures (46.5, 3.7-586.0), in-flowing blood vessels (9.3, 1.1-78.5), and unclear boundaries (109.0, 1.1-1110.0) significantly predicted surgical difficulty. These factors were used to construct a 0-4 point scoring system (with one point per variable). On cross-validation, the accuracy of the scoring system was 82.4% (Cohen's kappa of 0.57). ROC analysis showed that scores ≥ 2 predicted surgical difficulty with sensitivity and specificity of 55% and 98%, respectively. CONCLUSIONS: Our scoring system accurately predicted lipoma resection difficulty and may help operators prepare, thereby facilitating surgery.

DOI： 10.1007/s13555-022-00820-z

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OBJECTIVE: The process of cerebral arteriovenous malformation (AVM) obliteration following radiosurgery is poorly understood. Authors of this retrospective study aimed to assess the changes in AVM hemodynamics after stereotactic radiosurgery (SRS) by using 3D flow magnetic resonance imaging (MRI) to elucidate the process of AVM obliteration. METHODS: Twenty-four patients with AVMs treated with SRS between July 2015 and December 2017 were included in this study and classified into two groups depending on the duration of AVM obliteration: group A, obliteration within 3 years (n = 15); and group B, obliteration taking more than 3 years or no obliteration (n = 9). Blood flow (ml/min) in the largest feeding artery was measured before and after SRS by using time-averaged 3D flow MRI. The decreasing rate of blood flow in the feeding artery after SRS was calculated as the percent change from baseline blood flow. A Wilcoxon rank-sum test was used to compare the decreasing blood flow rate between the two groups at 4 and 12 months after SRS. RESULTS: For the entire cohort, the mean decrease in blood flow in the feeding artery from baseline was 29% at 4 months and 71% at 12 months after SRS. In general, blood flow after SRS decreased faster in group A and slower in group B. The decreasing rates in blood flow at 4 and 12 months after SRS were significantly different between the two groups (p = 0.02 and < 0.001, respectively). CONCLUSIONS: Tracking changes in AVM hemodynamics after SRS may be useful for assessing the progress of AVM obliteration and the therapeutic effects of SRS, possibly contributing to the prediction of subsequent obliteration outcome.

DOI： 10.3171/2022.4.FOCUS2214

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Most cardiac diseases cause a non-physiological blood flow pattern known as turbulence around the heart and great vessels, which further worsen the disease itself. However, there is no consensus on how blood flow can be defined in disease conditions. Especially, in the left atrium, the fact that vortex flow already exists makes this debate more complicated. 3D time-resolved phase-contrast (4D flow) MRI is expected to be able to capture blood flow patterns from multiple aspects, such as blood flow velocity, stasis, and vortex quantification. Previous studies have confirmed that physiological vortex flow is predominantly induced by the higher-volume flow from the superior left pulmonary vein. In atrial fibrillation, 4D flow MRI reveals a non-physiological blood flow pattern, which information may add value to well-established clinical risk factors. Currently, the research target of LA analysis has also widened to lung surgeons, pulmonary vein stump thrombosis after left upper lobectomy. 4D flow MRI is expected to be utilized for many more variable diseases that are currently unimaginable.

DOI： 10.2463/mrms.rev.2021-0137

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This special issue of Magnetic Resonance in Medical Sciences features the most recent reviews on 4D Flow MRI. These reviews deal with the current status of the emerging technique of 4D Flow MRI facilitated in various areas that are difficult to obtain with conventional flowmetry. MR signals inherently contain flow velocity information. In previous decades, in vivo blood flow measurement was traditionally performed by 2D methods, such as Doppler ultrasonography and 2D phase-contrast MRI, which have long been regarded as mature techniques in hemodynamic flowmetry. Although 2D velocimetries have many advantages over 4D Flow MRI in terms of cost and accessibility, and provide excellent temporal and in-plane spatial resolutions, they also have some disadvantages. The emerging technology of 4D Flow MRI can overcome the shortcomings of conventional 2D imaging. In recent years, hemodynamic analysis has witnessed significant progress that is primarily attributable to advances in 4D Flow MRI.

DOI： 10.2463/mrms.e.2022-1000

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Blood flow imaging becomes an emerging trend in cardiology with the recent progress in computer technology. It not only visualizes colorful flow velocity streamlines but also quantifies the mechanical stress on cardiovascular structures; thus, it can provide the detailed inspections of the pathophysiology of diseases and predict the prognosis of cardiovascular functions. Clinical applications include the comprehensive assessment of hemodynamics and cardiac functions in echocardiography vector flow mapping (VFM), 4D flow MRI, and surgical planning as a simulation medicine in computational fluid dynamics (CFD).For evaluation of the hemodynamics, novel mathematically derived parameters obtained using measured velocity distributions are essential. Among them, the traditional and typical parameters are wall shear stress (WSS) and its related parameters. These parameters indicate the mechanical damages to endothelial cells, resulting in degenerative intimal change in vascular diseases. Apart from WSS, there are abundant parameters that describe the strength of the vortical and/or helical flow patterns. For instance, vorticity, enstrophy, and circulation indicate the rotating flow strength or power of 2D vortical flows. In addition, helicity, which is defined as the cross-linking number of the vortex filaments, indicates the 3D helical flow strength and adequately describes the turbulent flow in the aortic root in cases with complicated anatomies. For the description of turbulence caused by the diseased flow, there exist two types of parameters based on completely different concepts, namely: energy loss (EL) and turbulent kinetic energy (TKE). EL is the dissipated energy with blood viscosity and evaluates the cardiac workload related to the prognosis of heart failure. TKE describes the fluctuation in kinetic energy during turbulence, which describes the severity of the diseases that cause jet flow. These parameters are based on intuitive and clear physiological concepts, and are suitable for in vivo flow measurements using inner velocity profiles.

DOI： 10.2463/mrms.rev.2021-0097

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BACKGROUND: Maintaining the patency of extracranial-to-intracranial (EC-IC) bypass is critical for long-term stroke prevention. However, reports on the factors influencing long-term bypass patency and quantitative assessments of bypass patency are limited. OBJECTIVE: To quantitatively evaluate blood flow in EC-IC bypass using four-dimensional (4D) flow magnetic resonance imaging (MRI) and investigate factors influencing the long-term patency of EC-IC bypass. METHODS: Thirty-six adult Japanese patients who underwent EC-IC bypass for symptomatic internal carotid or middle cerebral artery occlusive disease were included. We examined the relationships between decreased superficial temporal artery (STA) blood flow volume and perioperative complications, long-term ischemic complications, patient background, and postoperative antithrombotic medications in patients for whom STA flow could be quantitatively assessed for at least 5 months using 4D flow MRI. RESULTS: The mean follow-up time was 54.7 ± 6.1 months. One patient presented with a stroke during the acute postoperative period that affected postoperative outcomes. No recurrent strokes were recorded during long-term follow-up. Two patients died of malignant disease. Seven cases of reduced flow occurred in the STA, which were correlated with single bypass (P = .0294) and nonuse of cilostazol (P = .0294). STA occlusion was observed in 1 patient during the follow-up period. Hypertension, age, smoking, dyslipidemia, and diabetes mellitus were not correlated with reduced blood flow in the STA. CONCLUSION: Double anastomoses and cilostazol resulted in long-term STA blood flow preservation. No recurrence of cerebral infarction was noted in either STA hypoperfusion or occlusion cases.

DOI： 10.1227/NEU.0000000000001846

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BACKGROUND: Four-dimensional flow magnetic resonance imaging (4D flow MRI) can directly estimate turbulent kinetic energy (TKE) which is associated with pressure loss that are not assessable by other imaging modalities. METHODS AND RESULTS: A 55-year-old woman developed hemolytic anemia after emergency ascending aortic replacement for acute type A aortic dissection. Although computed tomographic angiography or doppler echocardiography could not identify the culprit stenotic legion, 4D flow MRI revealed jet flow and highly elevated TKE at the highly stenosed proximal anastomosis of a replaced ascending aorta. CONCLUSION: Our findings suggest that 4D flow MRI evaluation and TKE estimation enable more accurate and detailed assessment of abnormal flow dynamics than conventional imaging modalities.

DOI： 10.1111/jocs.16205

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Accurate prostate cancer screening is imperative for reducing the risk of cancer death. Ultrasound imaging, although easy, tends to have low resolution and high inter-observer variability. Here, we show that our integrated machine learning approach enabled the detection of pathological high-grade cancer by the ultrasound procedure. Our study included 772 consecutive patients and 2899 prostate ultrasound images obtained at the Nippon Medical School Hospital. We applied machine learning analyses using ultrasound imaging data and clinical data to detect high-grade prostate cancer. The area under the curve (AUC) using clinical data was 0.691. On the other hand, the AUC when using clinical data and ultrasound imaging data was 0.835 (p = 0.007). Our data-driven ultrasound approach offers an efficient tool to triage patients with high-grade prostate cancers and expands the possibility of ultrasound imaging for the prostate cancer detection pathway.

DOI： 10.1038/s41598-022-04951-3

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Purpose: To investigate the reproducibility of tracer uptake measurements, including volume metrics, such as metabolic tumor volume (MTV) and tumor lesion glycolysis (TLG) obtained by TOF-PET-CT and TOF-PET-MR. Materials and Methods: Eighty consecutive patients with different oncologic diagnoses underwent TOF-PET-CT (Discovery 690; GE Healthcare) and TOF-PET-MR (SIGNA PET-MR; GE Healthcare) on the same day with single dose-18F-FDG injection. The scan order, PET-CT following or followed by PET-MR, was randomly assigned. A spherical volume of interest (VOI) of 30 mm was placed on the liver in accordance with the PERCIST criteria. For liver, the maximum and mean standard uptake value for body weight (SUV) and lean body mass (SUL) were obtained. For tumor delineation, VOI with a threshold of 40 and 50% of SUVmax was used (VOI40 and VOI50). The SUVmax, SUVmean, SUVpeak, MTV and TLG were calculated. The measurements were compared between the two scanners. Results: In total, 80 tumor lesions from 35 patients were evaluated. There was no statistical difference observed in liver regions, whereas in tumor lesions, SUVmax, SUV mean, and SUVpeak of PET-MR were significantly underestimated (p < 0.001) in both VOI40 and VOI50. Among volume metrics, there was no statistical difference observed except TLG on VOI50 (p = 0.03). Correlation between PET-CT and PET-MR of each metrics were calculated. There was a moderate correlation of the liver SUV and SUL metrics (r = 0.63-0.78). In tumor lesions, SUVmax and SUVmean had a stronger correlation with underestimation in PET-MR on VOI 40 (SUVmax and SUVmean; r = 0.92 and 0.91 with slope = 0.71 and 0.72, respectively). In the evaluation of MTV and TLG, the stronger correlations were observed both on VOI40 (MTV and TLG; r = 0.75 and 0.92) and VOI50 (MTV and TLG; r = 0.88 and 0.95) between PET-CT and PET-MR. Conclusion: PET metrics on TOF-PET-MR showed a good correlation with that of TOF-PET-CT. SUVmax and SUVpeak of tumor lesions were underestimated by 16% on PET-MRI. MTV with % threshold can be regarded as identical volumetric markers for both TOF-PET-CT and TOF-PET-MR.

DOI： 10.3389/fmed.2022.796085

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society of Neuroradiology ({ASNR})  

BACKGROUND AND PURPOSE: The hemodynamics associated with cerebral AVMs have a significant impact on their clinical presentation. This study aimed to evaluate the hemodynamic features of AVMs using 3D phase-contrast MR imaging with dual velocity-encodings.MATERIALS AND METHODS: Thirty-two patients with supratentorial AVMs who had not received any previous treatment and had undergone 3D phase-contrast MR imaging were included in this study. The nidus diameter and volume were measured for classification of AVMs (small, medium, or large). Flow parameters measured included apparent AVM inflow, AVM inflow index, apparent AVM outflow, AVM outflow index, and the apparent AVM inflow-to-outflow ratio. Correlation coefficients between the nidus volume and each flow were calculated. The flow parameters between small and other AVMs as well as between nonhemorrhagic and hemorrhagic AVMs were compared.RESULTS: Patients were divided into hemorrhagic (n = 8) and nonhemorrhagic (n = 24) groups. The correlation coefficient between the nidus volume and the apparent AVM inflow and outflow was .83. The apparent AVM inflow and outflow in small AVMs were significantly smaller than in medium AVMs (P < .001 for both groups). The apparent AVM inflow-to-outflow ratio was significantly larger in the hemorrhagic AVMs than in the nonhemorrhagic AVMs (P = .02).CONCLUSIONS: The apparent AVM inflow-to-outflow ratio was the only significant parameter that differed between nonhemorrhagic and hemorrhagic AVMs, suggesting that a poor drainage system may increase AVM pressure, potentially causing cerebral hemorrhage.

DOI： 10.3174/ajnr.A7314

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BACKGROUND: Sepsis is often associated with multiple organ failure; however, changes in brain volume with sepsis are not well understood. We assessed brain atrophy in the acute phase of sepsis using brain computed tomography (CT) scans, and their findings' relationship to risk factors and outcomes. METHODS: Patients with sepsis admitted to an intensive care unit (ICU) and who underwent at least two head CT scans during hospitalization were included (n = 48). The first brain CT scan was routinely performed on admission, and the second and further brain CT scans were obtained whenever prolonged disturbance of consciousness or abnormal neurological findings were observed. Brain volume was estimated using an automatic segmentation method and any changes in brain volume between the two scans were recorded. Patients with a brain volume change < 0% from the first CT scan to the second CT scan were defined as the "brain atrophy group (n = 42)", and those with ≥ 0% were defined as the "no brain atrophy group (n = 6)." Use and duration of mechanical ventilation, length of ICU stay, length of hospital stay, and mortality were compared between the groups. RESULTS: Analysis of all 42 cases in the brain atrophy group showed a significant decrease in brain volume (first CT scan: 1.041 ± 0.123 L vs. second CT scan: 1.002 ± 0.121 L, t (41) = 9.436, p < 0.001). The mean percentage change in brain volume between CT scans in the brain atrophy group was -3.7% over a median of 31 days, which is equivalent to a brain volume of 38.5 cm3. The proportion of cases on mechanical ventilation (95.2% vs. 66.7%; p = 0.02) and median time on mechanical ventilation (28 [IQR 15-57] days vs. 15 [IQR 0-25] days, p = 0.04) were significantly higher in the brain atrophy group than in the no brain atrophy group. CONCLUSIONS: Many ICU patients with severe sepsis who developed prolonged mental status changes and neurological sequelae showed signs of brain atrophy. Patients with rapidly progressive brain atrophy were more likely to have required mechanical ventilation.

DOI： 10.1186/s13054-021-03828-7

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The ring finger protein 213 (RNF213) susceptibility gene has been detected in more than 80% of Japanese and Korean patients with moyamoya disease (MMD), a bilateral internal carotid artery (ICA) occlusion. Furthermore, RNF213 has been detected in more than 20% of East Asians with atherosclerotic ICA stenosis. In this study, we evaluated the frequency of RNF213 mutations in congenital occlusive lesions of the ICA system. This case series was conducted jointly at four university hospitals. Patients with a family history of MMD, quasi-MMD, or related diseases were excluded. Ten patients were diagnosed with abnormal ICA or middle cerebral artery (MCA) angiogenesis. Patients with neurofibromatosis were excluded. Finally, nine patients with congenital vascular abnormalities were selected; of these, five had ICA deficiency and four had twig-like MCA. The RNF213 c.14576G > A mutation was absent in all patients. Therefore, the RNF213 c.14576G > A mutation may not be associated with ICA and MCA congenital dysplasia-rare vascular anomalies making it difficult to study a large number of cases. However, an accumulation of cases is required for accurate determination. The results of this study may help differentiate congenital vascular diseases from MMD.

DOI： 10.1038/s41598-021-01623-6

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A mutation in RNF213 (c.14576G>A), a gene associated with moyamoya disease (>80%), plays a role in terminal internal carotid artery (ICA) stenosis (>15%) (ICS). Studies on RNF213 and cerebral aneurysms (AN), which did not focus on the site of origin or morphology, could not elucidate the relationship between the two. However, a report suggested a relationship between RNF213 and AN in French-Canadians. Here, we investigated the relationship between ICA saccular aneurysm (ICA-AN) and RNF213. We analyzed RNF213 expression in subjects with ICA-AN and atherosclerotic ICS. Cases with a family history of moyamoya disease were excluded. AN smaller than 4 mm were confirmed as AN only by surgical or angiographic findings. RNF213 was detected in 12.2% of patients with ICA-AN and 13.6% of patients with ICS; patients with ICA-AN and ICS had a similar risk of RNF213 mutation expression (odds ratio, 0.884; 95% confidence interval, 0.199-3.91; p = 0.871). The relationship between ICA-AN and RNF213 (c.14576G>A) was not correlated with the location of the ICA and bifurcation, presence of rupture, or multiplicity. When the etiology and location of AN were more restricted, the incidence of RNF213 mutations in ICA-AN was higher than that reported in previous studies. Our results suggest that strict maternal vessel selection and pathological selection of AN morphology may reveal an association between genetic mutations and ICA-AN development. The results of this study may form a basis for further research on systemic vascular diseases, in which the RNF213 (c.14576G>A) mutation has been implicated.

DOI： 10.3390/genes12101468

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Despite the recent technical developments, surgery on the thoracic aorta remains challenging and is associated with significant mortality and morbidity. Decisions about when and if to operate are based on a balance between surgical risk and the hazard of aortic rupture. These decisions are sometimes difficult in elective cases of thoracic aortic diseases, including aneurysms and dissections. Abnormal wall stress derived from flow alterations influences disease progression. Therefore, a better understanding of the complex hemodynamic environment inside the aortic lumen will facilitate patient-specific risk assessments of complications, which enable clinicians to provide timely prophylactic interventions. Time-resolved 3D phase-contrast (4D flow) MRI has many advantages for the in vivo assessment of flow dynamics. Recent developments in 4D flow imaging techniques has led to significant advances in our understanding of physiological flow dynamics in healthy subjects and patients with thoracic aortic diseases. In this clinically focused review of thoracic aortic diseases, we demonstrate the clinical advances acquired with 4D flow MRI from published studies. We provide a systematic overview of key evidences and considerations regarding normal thoracic aortas, thoracic aortic aneurysms, aortic dissections, and thoracic aortas with prosthetic graft replacement.

DOI： 10.2463/mrms.rev.2021-0046

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OBJECTIVE: To examine the relationship between trap location and cerebral infarction in the anterior choroidal artery (AChA) region and associated risks in ruptured internal carotid artery blood blister-like aneurysm (BLA) treatment with high-flow bypass and lesion trapping. METHODS: We included 26 patients diagnosed with BLAs and treated with high-flow bypass and trapping. We examined clinical characteristics including age, aneurysm trap location, final prognosis, cerebral infarction on postoperative magnetic resonance imaging, and modified Rankin Scale score at discharge. We also searched the literature for similar studies. RESULTS: The modified Rankin Scale score at discharge was 0-2 in 20 patients, 3-5 in 2 patients, and 6 in 2 patients. In 19/26 patients (73.1%), the trapped segment was between the posterior communicating (PcomA) and the ophthalmic arteries. In 2 patients (7.7%), the trapped segment included the PcomA and the AChA; in 4 patients (15.4%), the trapped segment was within the PcomA. In these patients, the PcomA was occluded, and blood from the high-flow bypass flowed out to the AChA alone. No patient showed cerebral infarction. Our systematic review identified 70 patients. Of all 96 patients, 12 had AChA cerebral infarction; however, the infarction affected the prognosis of only 2 patients. CONCLUSIONS: When treating BLAs with high-flow bypass and lesion trapping, the frequency of AChA cerebral infarction is low even when the PcomA is occluded, leaving the AChA as the only outflow vessel during high-flow bypass. However, PcomA occlusion may be associated with risks when treating patients with advanced arteriosclerosis near C1-2.

DOI： 10.1016/j.wneu.2021.06.084

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BACKGROUND: The hemodynamic changes after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery are unclear. OBJECTIVE: To clarify the hemodynamics by comparing flow parameters obtained by 4-dimensional (4D) flow magnetic resonance imaging (MRI) and intraoperative MCA pressure measurement. METHODS: We recruited 23 patients who underwent STA-MCA bypass surgery for internal carotid artery (ICA) or MCA stenosis. We monitored intraoperative MCA, STA, and radial artery (RA) pressure. All patients underwent 4D flow MRI preoperatively and 3 wk after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), contralateral ICA (BFVcICA), basilar artery (BFVBA), ipsilateral STA (BFViSTA), and contralateral STA (BFVcSTA). The sum of intracranial BFV was defined as BFVtotal. We compared BFV parameters and intraoperative pressure. RESULTS: BFViSTA significantly increased after surgery (P < .001). BFViICA and BFVBA significantly decreased after surgery (BFViICAP = .005; BFVBAP = .02). No significant difference was observed between BFVcICA before and after surgery. As a result, BFVtotal postoperatively increased by 6.8%; however, no significant difference was observed. Flow direction at M1 changed from antegrade to unclear after surgery in 5 patients. Intraoperative MCA pressure and MCA/RA pressure ratio significantly increased after surgery (P < .001). We found a stronger positive correlation between MCA pressure increase ratio and BFVtotal increase ratio in patients with lower pre-MCA pressure (r = 0.907, P < .001). CONCLUSION: The visual and quantitative assessment of 4D flow MRI revealed that intracranial blood flow changes complementarily after STA-MCA bypass surgery. 4D flow MRI may detect the improvement of cerebral perfusion pressure.

DOI： 10.1093/neuros/nyab305

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This Editorial Comment discusses the following AJR article: Structural Heart 4D Flow MRI for Hemodynamic Assessment: How We Do It.

DOI： 10.2214/AJR.21.26333

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OBJECTIVES: This study aimed to explore the flow dynamics factors affecting turbulence formation in the false lumen (FL) of aortic dissection using four-dimensional flow magnetic resonance imaging (4D flow MRI). This study also aimed to uncover risk factors affecting late complications of aortic dissection. METHODS: Thirty-three aortic dissection patients were examined using 4D flow MRI for quantitative flow dynamics (gross flow, velocity and regurgitant fraction) and turbulence visualization (helix and vortex with three-point visual grading) in the FL. The incidence of late complications (rupture or prophylactic intervention) was also obtained prospectively. RESULTS: The helix grade was correlated with FL gross flow (rS = 0.55, P < 0.001) and FL velocity (rS = 0.45, P = 0.008). The vortex grade was also correlated with FL gross flow (rS = 0.70, P < 0.001) and FL velocity (rS = 0.67, P < 0.001). Comparative analysis of patients with complications and stable patients revealed that patients with complications exhibited higher FL gross flow [41.7 (interquartile range, IQR 29.1-59.7) vs 17.7 (IQR 9.0-42.0) ml/s; P = 0.01], higher helix grade [2 (IQR 1.25-2) vs 0 (IQR 0-1); P = 0.001] and higher vortex grade [2 (IQR 1-2) vs 0 (IQR 0-2); P = 0.01]. CONCLUSIONS: Using 4D flow MRI analysis, we showed that turbulence formation depends on flow volume and velocity in the FL. Patients with high-volume turbulent flow in their FL are at higher risk of late complications; therefore, close follow-up and aggressive prophylactic intervention may improve their survival. CLINICAL TRIAL REGISTRATION NUMBER: Nippon Medical School Hospital Institutional Review Board approved this observational study in September 2018 (No. 30-08-986).

DOI： 10.1093/ejcts/ezab201

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PURPOSE: The purpose of the current study was to clarify the blood flow pattern in the left atrium (LA), potentially causing the formation of thrombosis after left upper lobectomy (LUL). The blood flow in the LA was evaluated and compared between LUL patients with and without thrombosis. For the evaluation, we applied highly accelerated 4D flow MRI with dual-velocity encoding (VENC) scheme, which was expected to be able to capture slow flow components in the LA accurately. METHODS: Eight volunteers and 18 patients subjected to LUL underwent dual-VENC 4D Flow MRI. Eight patients had a history of thrombosis. We measured the blood flow velocity and stasis ratio (proportion in the volume that did not exceed 10 cm/s in any cardiac phase) in the LA and left superior pulmonary vein (LSPV) stump. For visual assessment, the presence of each collision of the blood flow from pulmonary veins and vortex flow in the LA were evaluated. Each acquired value was compared between healthy participants and LUL patients, and in LUL patients with and without thrombosis. RESULTS: In LUL patients, blood flow velocity near the inflow part of the left superior pulmonary vein (Lt Upp) and mean velocity in the LA were lower, and stasis ratio in the LA was higher compared with healthy volunteers (Lt Upp 9.10 ± 3.09 vs.13.23 ± 14.19 cm/s, mean velocity in the LA 9.81 ± 2.49 vs. 11.40 ± 1.15 cm/s, and stasis ratio 25.28 ± 18.64 vs. 4.71 ± 3.03%, P = 0.008, 0.037, and < 0.001). There was no significant difference in any quantification values between LUL patients with and without thrombosis. For visual assessment, the thrombus formation was associated with no collision pattern (62.5% vs. 10%, P = 0.019) and not with vortex flow pattern (50% vs. 30%, P = 0.751). CONCLUSION: The net blood flow velocity was not associated with the thrombus formation. In contrast, a specific blood flow pattern, the absence of blood flow collision from pulmonary veins, correlates to the thrombus formation in the LA.

DOI： 10.2463/mrms.mp.2020-0170

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Language：English   Publisher：(一社)日本循環器学会  

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Language：English   Publisher：(一社)日本循環器学会  

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OBJECTIVES: This study investigated harmonized pretreatment volume-based quantitative FDG-PET/CT parameters in breast cancer patients for prognostic value. RESULTS: During a median overall follow-up period of 5.3 years, 91 patients had recurrence and 40 died. Multivariate analysis of ER-positive/HER2-negative patients showed high maximum standardized uptake value (SUVmax) (p = 0.018), high total lesion glycolysis (TLG) (p = 0.010), and clinical N-classification (p = 0.0027) as independent negative predictors of RFS, while high maximum SUVmax (p = 0.037), advanced clinical T-classification (p = 0.030), and advanced TNM stage (p = 0.0067) were independent negative predictors of OS. For recurrence and death in HER2-positive patients, high total TLG (p = 0.037, p = 0.0048, respectively) and advanced TNM stage (p = 0.048, p = 0.046, respectively) were independent prediction factors. In the triple-negative group, independent factors related to recurrence and death were high maximum SUVmax (p = 0.0014, p = 0.0003, respectively) and advanced TNM stage (p < 0.0001, p < 0.0001, respectively). MATERIALS AND METHODS: Records of 546 stage I-III invasive breast cancer patients, including 344 estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 110 HER2-positive, and 92 triple-negative cases, treated at four institutions were reviewed retrospectively. Harmonized primary tumor and nodal maximum SUVmax, metabolic tumor volume (MTV), and TLG indicated in pretreatment FDG-PET/CT results were analyzed. Evaluations of relationships of clinicopathological factors, volume-based quantitative parameters, recurrence-free survival (RFS), and overall survival (OS) for each subtype were performed with a Cox proportional hazards model and log-rank test. CONCLUSIONS: The results indicated that potential surrogate markers for prognosis in patients with the three main subtypes of operable breast cancer include harmonized pretreatment quantitative volume-based FDG-PET/CT parameters, particularly whole-lesion SUVmax and TLG.

DOI： 10.18632/oncotarget.27851

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DOI： 10.21037/jtd-20-3229

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Objective Computed tomography (CT) can be used for visualizing acute intracerebral hemorrhages (ICHs) as distinct hyperdense areas and cerebral edema as perihematomal low-density areas (LDAs). We observed a perihematomal LDA on CT, which appeared to be part of a hemorrhage on magnetic resonance imaging (MRI) in acute ICH. We named this "CT perihematomal rim" and evaluated its characteristics and clinical significance. Methods We stratified patients with acute ICH according to the presence or absence of a CT perihematomal rim and then compared their radiologic findings. Logistic regression analyses were performed to assess whether the CT findings can predict the presence of a CT perihematomal rim. Patients Patients within 24 hours of ICH onset who were admitted between September 1, 2014, and October 31, 2018, were registered. Results Overall, 139 patients (91 men; mean age, 66 years) were investigated. CT perihematomal rims were observed in 40 patients (29%). ICH volumes on CT were 30% smaller than those on MRI in patients with CT perihematomal rims. On a multivariate analysis, the presence of a CT perihematomal rim was independently associated with the maximum diameter of the perihematomal LDA. According to a receiver operating characteristic analysis, the maximum LDA diameter threshold was 7.5 mm (sensitivity, 85%; specificity, 83%). Conclusion CT perihematomal rims were observed in 29% of the patients with acute ICH. A perihematomal LDA (>7.5 mm) in acute ICH cases should be considered a CT perihematomal rim. Clinicians should be aware that the ICH volume on CT may be underestimated by 30%.

DOI： 10.2169/internalmedicine.6653-20

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Aims: This study aimed to analyze the performance of multi-atlas MRI-based parcellation for 123I-FP-CIT SPECT (DAT-SPECT) in healthy volunteers. The proposed method was compared with the SPECT-atlas-based and Bolt methods. 18F-FE-PE2I-PET (DAT-PET) was used as a reference. Methods: Thirty healthy subjects underwent DAT-SPECT, DAT-PET, and 3D-T1WI-MRI. We calculated the striatum uptake ratio (SUR/SBR), caudate uptake ratio (CUR), and putamen uptake ratio (PUR) for DAT-SPECT using the multi-atlas MRI-based method, SPECT-atlas-based method, and Bolt method. In the multi-atlas MRI-based method, the cerebellum, occipital cortex, and whole-brain were used as reference regions. The correlation of age with DAT-SPECT activity and the correlations of SUR/SBR, CUR, and PUR between DAT-SPECT and DAT-PET were calculated by each of the three methods. Results: The correlation between age and SUR/SBR for DAT-SPECT based on the multi-atlas MRI-based method was comparable to that based on the SPECT-atlas-based method (r = -0.441 to -0.496 vs. -0.488). The highest correlation between DAT-SPECT and DAT-PET was observed using the multi-atlas MRI-based method with the occipital lobe defined as the reference region compared with the SPECT-atlas-based and Bolt methods (SUR, CUR, and PUR: 0.687, 0.723, and 0.676 vs. 0.698, 0.660, and 0.616 vs. 0.655). Conclusion: Multi-atlas MRI-based parcellation with the occipital lobe defined as the reference region was at least comparable to the clinical methods.

DOI： 10.3389/fmed.2021.662233

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PURPOSE: MRI-based risk stratification should be established to identify patients with internal carotid artery stenosis (ICS) who require further PET or SPECT evaluation. This study assessed whether multiparametric flow analysis using time-resolved 3D phase-contrast (4D flow) MRI can detect cerebral hemodynamic impairment in patients with ICS. METHODS: This retrospective study analyzed 26 consecutive patients with unilateral ICS (21 men; mean age, 71 years) who underwent 4D flow MRI and acetazolamide-stress brain perfusion SPECT. Collateral flow via the Willis ring was visually evaluated. Temporal mean flow volume rate (Net), pulsatile flow volume (ΔV), and pulsatility index (PI) at the middle cerebral artery were measured. Cerebral vascular reserve (CVR) was calculated from the SPECT dataset. Patients were assigned to the misery perfusion group if the CVR was < 10% and to the nonmisery perfusion group if the CVR was ≥ 10%. Parameters showing a significant difference in both groups were statistically evaluated. RESULTS: Affected side ΔV, ratio of affected to contralateral side Net (rNet), and ratio of affected to contralateral side ΔV were significantly correlated to CVR (p = 0.030, p = 0.010, p = 0.015, respectively). Absence of retrograde flow at the posterior communicating artery was observed in the misery perfusion group (p = 0.020). Combined cut-off values of the affected side ΔV (0.18 ml) and rNet (0.64) showed a sensitivity and specificity of 100% and 77.8%, respectively. CONCLUSION: Multiparametric flow analysis using 4D flow MRI can detect misery perfusion by comprehensively assessing blood flow data, including blood flow volume, pulsation, and collateral flow.

DOI： 10.1007/s00234-020-02464-2

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DOI： 10.1148/rg.2020200177

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Language：English   Publisher：(一社)日本癌治療学会  

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Objective: The prognostic value of harmonized pretreatment volume-based quantitativefluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) parameters in metastatic breast cancer patients was investigated. Subjects and Methods: Records of 65 stage IV breast cancer patients, including 29 estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 23 HER2-positive, and 13 triple-negative cases, from four different institutions were retrospectively reviewed. Harmonized standardized uptake value (SUVmax) of the primary tumor (pSUVmax), highest SUVmax of all malignant lesions (wSUVmax), whole-body metabolic tumor volume (WB MTV), and whole-body total lesion glycolysis (WB TLG) shown by pretreatment 18F-FDG PET/CT imaging were calculated. Cox proportional hazards model and log-rank test results were used to evaluate relationships among clinicopathological factors, volume-based quantitative 18F-FDG PET/CT parameters, progression-free survival, and overall survival (OS). Results: Disease progression occurred in 54 patients and 28 died during a median follow-up period of 52.5 months (range 2.6-133.6 months). Univariate analysis of all cases showed associations of negative ER and progesterone receptor (PR) status (P=0.0025), and high T/N stage (P=0.037/P=0.019), pSUVmax (P=0.049), WB MTV (P=0.021), and WB TLG (P=0.0010) with significantly shorter OS. Multivariate analysis confirmed negative ER and PR status (hazard ratio [HR]: 6.42, 95% confidence interval [CI]: 2.27-19.38; P=0.0054), high T stage (HR: 5.10, 95% CI:1.96-18.61, P=0.0064) and WB TLG (HR: 4.69, 95% CI:1.67-12.79, P=0.049) as independent negative OS predictors. In two groups of ER-positive/HER2-negative and triple-negative, WB TLG had a significant association with death (P= 0.021 and P=0.037, respectively) on univariate analysis. In a HER2-positive group, no independent negative OS predictors were observed. Conclusion: In metastatic breast cancer patients, harmonized pretreatment quantitative volume-based 18F-FDG PET/CT parameters, especially whole-body TLG, are potential surrogate markers for prognosis.

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DOI： 10.2214/AJR.20.23435

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BACKGROUND: While high body mass index (BMI) and visceral obesity are reportedly associated with a prolonged duration of laparoscopic radical nephrectomy (LRN) via the transperitoneal approach, factors that might prolong the retroperitoneal approach remain unknown. We therefore investigated factors associated with prolonged LRN using a retroperitoneal approach applied by non-expert surgeons. METHODS: We defined surgeons who were not certified to perform laparoscopic surgery by the Japanese Society of Endourology as non-experts. We retrospectively reviewed the medical records of 59 consecutive patients with renal cell carcinoma treated with LRN using the retroperitoneal approach by non-experts at our hospital between 2014 and 2019. Relationships between surgical duration and age, sex, body mass index, visceral fat area (VFA) and subcutaneous fat area (SFA), laterality and location of the tumor, length of major tumor axis (tumor length), clinical T stage, ipsilateral adrenalectomy and specimen weight were analyzed using Spearman rank correlation coefficients. RESULTS: The surgical duration positively correlated with ipsilateral adrenalectomy (rs = 0.3162, p = 0.0147) and specimen weight (rs = 0.3103, p = 0.0168), but not with BMI (rs = 0.2016, p = 0.1257) or VFA (rs = 0.0185, p = 0.8894). CONCLUSIONS: Factors associated with prolonged LRN via the retroperitoneal approach implemented by non-expert surgeons are ipsilateral adrenalectomy and specimen weight.

DOI： 10.1272/jnms.JNMS.2021_88-302

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DOI： 10.1093/eurheartj/ehz618

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We present the case of a 76-year-old woman who underwent left upper lobectomy for lung adenocarcinoma. Three days after the surgery, a thrombus was observed in the pulmonary vein (PV) stump. Four months after the surgery, we performed 4D flow MRI, which revealed decreased blood flow, not only in the left superior PV stump, but also over a widespread region around the left atrium-left superior PV junction. 4D flow MRI can clarify the altered hemodynamics underlying thrombus formation.

DOI： 10.2463/mrms.ici.2019-0142

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Language：Japanese   Publisher：(一社)日本磁気共鳴医学会  

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BACKGROUND: The purpose of this study was to assess the impact of vendor-provided atlas-based MRAC on FDG PET/MR for the evaluation of Alzheimer's disease (AD) by using simulated images. METHODS: We recruited 47 patients, from two institutions, who underwent PET/CT and PET/MR (GE SIGNA) examination for oncological staging. From the PET raw data acquired on PET/MR, two FDG-PET series were generated, using vendor-provided MRAC (atlas-based) and CTAC. The following simulation steps were performed in MNI space: After spatial normalization and smoothing of the PET datasets, we calculated the error map for each patient, PETMRAC/PETCTAC. We multiplied each of these 47 error maps with each of the 203 Alzheimer's Disease Neuroimaging Initiative (ADNI) cases after the identical normalization and smoothing. This resulted in 203*47 = 9541 datasets. To evaluate the probability of AD in each resulting image, a cumulative t-value was calculated automatically using commercially-available software (PMOD PALZ) which has been used in multiple large cohort studies. The diagnostic accuracy for the discrimination of AD and predicting progression from mild cognitive impairment (MCI) to AD were evaluated in simulated images compared with ADNI original images. RESULTS: The accuracy and specificity for the discrimination of AD-patients from normal controls were not substantially impaired, but sensitivity was slightly impaired in 5 out of 47 datasets (original vs. error; 83.2% [CI 75.0%-89.0%], 83.3% [CI 74.2%-89.8%] and 83.1% [CI 75.6%-88.3%] vs. 82.7% [range 80.4-85.0%], 78.5% [range 72.9-83.3%,] and 86.1% [range 81.4-89.8%]). The accuracy, sensitivity and specificity for predicting progression from MCI to AD during 2-year follow-up was not impaired (original vs. error; 62.5% [CI 53.3%-69.3%], 78.8% [CI 65.4%-88.6%] and 54.0% [CI 47.0%-69.1%] vs. 64.8% [range 61.5-66.7%], 75.7% [range 66.7-81.8%,] and 59.0% [range 50.8-63.5%]). The worst 3 error maps show a tendency towards underestimation of PET scores. CONCLUSION: FDG-PET/MR based on atlas-based MR attenuation correction showed similar diagnostic accuracy to the CT-based method for the diagnosis of AD and the prediction of progression of MCI to AD using commercially-available software, although with a minor reduction in sensitivity.

DOI： 10.1371/journal.pone.0233886

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Aim: Attenuation correction using zero-echo time (ZTE) - magnetic resonance imaging (MRI) (ZTE-MRAC) has become one of the standard methods for brain-positron emission tomography (PET) on commercial PET/MR scanners. Although the accuracy of the net tracer-uptake quantification based on ZTE-MRAC has been validated, that of the diagnosis for dementia has not yet been clarified, especially in terms of automated statistical analysis. The aim of this study was to clarify the impact of ZTE-MRAC on the diagnosis of Alzheimer's disease (AD) by performing simulation study. Methods: We recruited 27 subjects, who underwent both PET/computed tomography (CT) and PET/MR (GE SIGNA) examinations. Additionally, we extracted 107 subjects from the Alzheimer Disease Neuroimaging Initiative (ADNI) dataset. From the PET raw data acquired on PET/MR, three FDG-PET series were generated, using two vendor-provided MRAC methods (ZTE and Atlas) and CT-based AC. Following spatial normalization to Montreal Neurological Institute (MNI) space, we calculated each patient's specific error maps, which correspond to the difference between the PET image corrected using the CTAC method and the PET images corrected using the MRAC methods. To simulate PET maps as if ADNI data had been corrected using MRAC methods, we multiplied each of these 27 error maps with each of the 107 ADNI cases in MNI space. To evaluate the probability of AD in each resulting image, we calculated a cumulative t-value using a fully automated method which had been validated not only in the original ADNI dataset but several multi-center studies. In the method, PET score = 1 is the 95% prediction limit of AD. PET score and diagnostic accuracy for the discrimination of AD were evaluated in simulated images using the original ADNI dataset as reference. Results: Positron emission tomography score was slightly underestimated both in ZTE and Atlas group compared with reference CTAC (-0.0796 ± 0.0938 vs. -0.0784 ± 0.1724). The absolute error of PET score was lower in ZTE than Atlas group (0.098 ± 0.075 vs. 0.145 ± 0.122, p < 0.001). A higher correlation to the original PET score was observed in ZTE vs. Atlas group (R2: 0.982 vs. 0.961). The accuracy for the discrimination of AD patients from normal control was maintained in ZTE and Atlas compared to CTAC (ZTE vs. Atlas. vs. original; 82.5% vs. 82.1% vs. 83.2% (CI 81.8-84.5%), respectively). Conclusion: For FDG-PET images on PET/MR, attenuation correction using ZTE-MRI had superior accuracy to an atlas-based method in classification for dementia. ZTE maintains the diagnostic accuracy for AD.

DOI： 10.3389/fnins.2020.569706

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PURPOSE: To determine the clinically acceptable level of reduction in the injected fluorine-18 (18F)-labeled fluorodeoxyglucose (18F-FDG) dose in dedicated breast positron emission tomography (dbPET). METHODS: A breast phantom with four spheres exhibiting various diameters (5, 7.5, 10, and 16 mm), a background 18F-FDG radioactivity of 2.28 kBq/mL, and a sphere-to-background radioactivity ratio of 8:1 was used. True dose-reduced dbPET images were obtained by data acquisition for 20 min in list mode at multiple time points over 7 h of radioactive decay. Simulated dose-reduced images were generated by reconstruction with a portion of the list mode acquisition data. True and simulated dose-reduced images were visually and quantitatively compared. On the basis of the phantom study, dbPET images for 32 breasts of 28 women with abnormal uptake were generated after simulated reduction of the injected 18F-FDG doses; these images were compared with those acquired using current clinical doses. RESULTS: There were no qualitative differences between true and simulated dose-reduced phantom images. The phantom study revealed that the minimal required dose was 12.5% for the detection of 5-mm spheres and 25% for precise semi-quantification of FDG in the spheres. The 7-min reconstruction with a 100% dose was defined as the reference for the clinical study. The image quality and lesion conspicuity were clinically acceptable for the 25% dose images. Lesion detectability on the 12.5% dose images was maintained despite image quality degradation. CONCLUSIONS: In summary, 25% of the standard 18F-FDG dose for dbPET can provide a clinically acceptable image quality, while 12.5% of the standard dose results in acceptable quality in terms of lesion detection when lesions are located at a sufficient distance from the edge of the dbPET detector.

DOI： 10.1186/s40658-019-0256-9

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Deep learning algorithms have achieved great success in cancer image classification. However, it is imperative to understand the differences between the deep learning and human approaches. Using an explainable model, we aimed to compare the deep learning-focused regions of magnetic resonance (MR) images with cancerous locations identified by radiologists and pathologists. First, 307 prostate MR images were classified using a well-established deep neural network without locational information of cancers. Subsequently, we assessed whether the deep learning-focused regions overlapped the radiologist-identified targets. Furthermore, pathologists provided histopathological diagnoses on 896 pathological images, and we compared the deep learning-focused regions with the genuine cancer locations through 3D reconstruction of pathological images. The area under the curve (AUC) for MR images classification was sufficiently high (AUC = 0.90, 95% confidence interval 0.87-0.94). Deep learning-focused regions overlapped radiologist-identified targets by 70.5% and pathologist-identified cancer locations by 72.1%. Lymphocyte aggregation and dilated prostatic ducts were observed in non-cancerous regions focused by deep learning. Deep learning algorithms can achieve highly accurate image classification without necessarily identifying radiological targets or cancer locations. Deep learning may find clues that can help a clinical diagnosis even if the cancer is not visible.

DOI： 10.3390/biom9110673

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Language：Japanese   Publisher：日本医科大学医学会  

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Language：Japanese   Publisher：(一社)日本脈管学会  

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Language：English   Publisher：(一社)日本核医学会  

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Language：Japanese   Publisher：(一社)日本心臓病学会  

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Language：English   Publisher：(公社)日本医学放射線学会  

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BACKGROUND: The hemodynamic changes that occur after high-flow (extracranial-intracranial) EC-IC bypass surgery with internal carotid artery (ICA) ligation are not well known. OBJECTIVE: To assess blood flow changes after high-flow EC-IC bypass with ICA ligation by time-resolved 3-dimensional phase-contrast (4D Flow) magnetic resonance imaging (MRI). METHODS: We enrolled 11 patients who underwent high-flow EC-IC bypass. 4D Flow MRI was performed before and after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), bypass artery (BFVbypass), contralateral ICA (BFVcICA), and basilar artery (BFVBA). Subsequently, we calculated the total BFV (BFVtotal = BFViICA + BFVcICA + BFVBA [before surgery], BFVcICA + BFVBA + BFVbypass [after surgery]). The BFV changes after bypass was statistically analyzed. RESULTS: BFVbypass was slightly lower than BFViICA, but the difference was not statistically significant (3.84 ± 0.94 vs 4.42 ± 1.38 mL/s). The BFVcICA and BFVBA significantly increased after bypass surgery (BFVcICA 5.89 ± 1.44 vs 7.22 ± 1.37 mL/s [P = .0018], BFVBA 3.06 ± 0.41 vs 4.12 ± 0.38 mL/s [P < .001]). The BFVtotal significantly increased after surgery (13.37 ± 2.58 vs 15.18 ± 1.77 mL/s [P = .015]). There was no evidence of hyperperfusion syndrome in any cases. CONCLUSION: After high-flow EC-IC bypass with permanent ICA ligation, the bypass artery could partially compensate for the loss of BFV of the sacrificed ICA. The increased flow of the contralateral ICA and BA supply collateral blood flow. Clinically irrelevant hyperperfusion was observed.

DOI： 10.1093/neuros/nyy192

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Background The aims of the present study were to investigate the relationships between prior direct oral anticoagulant ( DOAC ) therapy and infarct volume and the site of arterial occlusion in patients with acute ischemic stroke and non-valvular atrial fibrillation. Methods and Results From March 2011 through November 2016, consecutive patients with acute ischemic stroke in the middle cerebral artery territory and non-valvular atrial fibrillation were recruited. The infarct volume was assessed semi-automatically using initial diffusion-weighted imaging, and the arterial occlusion site was evaluated on magnetic resonance angiography. The effect of prior DOAC treatment on the site of arterial occlusion was assessed by multivariate ordinal logistic regression analysis. A total of 330 patients (149 women; median age 79 [quartiles 71-86] years; median National Institutes of Health Stroke Scale score 11 [4-21]) were enrolled. Of these, 239 were on no anticoagulant, 40 were undertreated with a vitamin K antagonist ( VKA ), 22 were sufficiently treated with VKA ( PT - INR ≥1.6), and 29 were on a DOAC before the acute ischemic stroke. The infarct volume on admission differed among the groups (median 14.5 [2.0-59.8] cm3 in patients with no anticoagulation, 24.8 [2.1-63.0] in undertreated VKA , 1.3 [0.3-13.5] in sufficient VKA , and 2.3 [0.5-21.0] in DOAC , P=0.001). Multivariate analysis showed that prior DOAC treatment was independently and negatively associated with more proximal artery occlusion (odds ratio [OR] 0.34, P=0.015), compared with no anticoagulant. Conclusions DOAC treatment before the event was associated with smaller infarct volume and decreased risk of greater proximal artery occlusion in acute ischemic stroke patients with non-valvular atrial fibrillation, compared with no anticoagulation.

DOI： 10.1161/JAHA.118.009507

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Language：Japanese   Publisher：(一社)日本脈管学会  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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DOI： 10.1016/j.neuroimage.2018.07.029

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DOI： 10.2967/jnumed.118.209007

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BACKGROUND AND PURPOSE: To assess the clinical feasibility of time-resolved 3D phase contrast (4D Flow) MRI assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS). MATERIALS AND METHODS: Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed. The flow direction on the affected-side OphA was categorized into native flow (anterograde or unclear) and non-native flow (retrograde flow) based on 4D Flow MRI. In the affected-side middle cerebral artery (MCA) territory, the ratio of rest cerebral blood flow to normal control (RCBFMCA) and cerebral vascular reserve (CVRMCA) were calculated from SPECT dataset. High-risk patients were defined based on the previous large cohort study (RCBFMCA < 80% and CVRMCA < 10%). RESULTS: Eleven patients had native OphA flow (4 anterograde, 7 unclear) and the remaining 10 had non-native OphA flow. RCBFMCA and CVRMCA each were significantly lower in non-native flow group (84.9 ± 18.9% vs. 69.8 ± 7.3%, P < 0.05; 36.4 ± 20.6% vs. 17.0 ± 15.0%, P < 0.05). Four patients in the non-native flow group and none in the native flow group were confirmed as high-risk (Sensitivity/Specificity, 1.00/0.65). CONCLUSION: The 6 min standard 4D Flow MRI assessment of OphA in patients with ICS can predict intracranial hemodynamic impairment.

DOI： 10.2463/mrms.mp.2016-0074

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Radiological Society of North America Inc.  

Purpose: To determine the level of clinically acceptable reduction in injected fluorine 18 (18F) fluorodeoxyglucose (FDG) dose in time-of-flight (TOF)-positron emission tomography(PET)/ magnetic resonance (MR) imaging by using silicon photomultiplier (SiPM) detectors compared with TOF-PET/computed tomography (CT) using Lu1.8Y0.2SiO5(Ce), or LYSO, detectors in patients with different body mass indexes (BMIs). Materials and Methods: Patients were enrolled in this study as part of a larger prospective study with a different purpose than evaluated in this study (NCT02316431). All patients gave written informed consent prior to inclusion into the study. In this study, 74 patients with different malignant diseases underwent sequential whole-body TOF-PET/CT and TOFPET/ MR imaging. PET images with simulated reduction of injected 18F-FDG doses were generated by unlisting the list-mode data from PET/MR imaging. Two readers rated the image quality of whole-body data sets, as well as the image quality in each body compartment, and evaluated the conspicuity of malignant lesions. Results: The image quality with 70% or 60% of the injected dose of 18F-FDG at PET/MR imaging was comparable to that at PET/CT. With 50% of the injected dose, comparable image quality was maintained among patients with a BMI of less than 25 kg/m2. PET images without TOF reconstruction showed higher artifact scores and deteriorated sharpness than those with TOF reconstruction. Conclusion: Sixty percent of the usually injected 18F-FDG dose (reduction of up to 40%) in patients with a BMI of more than 25 kg/m2 results in clinically adequate PET image quality in TOF-PET/MR imaging performed by using SiPM detectors. Additionally, in patients with a BMI of less than 25 kg/m2, 50% of the injected dose may safely be used.

DOI： 10.1148/radiol.2017162305

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Medical Association of Nippon Medical School  

Background and Purpose: It is clinically important to evaluate time course changes in symptomatic middle cerebral artery (MCA) stenotic plaques because of likely recurrence. The objective of this study is to determine whether contrast-enhanced high-resolution magnetic resonance imaging (MRI) is a feasible method for this purpose. Methods: Contrast-enhanced, high-resolution, 3D turbo spin-echo images with low refocusing flip angle control (3D LOWRAT) applied to 7 patients with symptomatic MCA stenosis were evaluated at the initial (1 month after stroke onset) and follow-up (7 months after stroke onset) stages, and statistical variables, including plaque-to-thalamus signal intensity ratio, degree of stenosis, and stroke recurrence obtained at the 2 stages, were compared. Stenotic change at the initial stage was compared to that at the follow-up stage using MR angiography. Results: In 4 of the 7 patients, the signal intensity ratio measured at the follow-up stage was lower than that measured at the initial stage and in 1 patient, the stenosis subsequently improved. We used a Chi-Square Test. In the other 3 patients, the signal intensity ratios did not differ between the 2 stages, and ischemic stroke occurred in 2 of these 3 patients. Conclusion: Gadolinium contrast enhancement was found to be useful for effective evaluation of time course changes in the stability of symptomatic MCA stenotic plaques.

DOI： 10.1272/jnms.2018_85-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Background: The purpose of this study was to compare the diagnostic accuracy of positron emission tomography (PET)/MRI with PET/CT for local resectability of head and neck cancer.
Methods: Sequential contrast-enhanced PET/CT-MRI was performed in 58 patients referred for the staging or restaging of head and neck cancer. Tumors were assessed with PET/CT and PET/MRI for the presence of resectability-defining factors: T4b status (mediastinal invasion, invasion of the prevertebral space, and vascular encasement), and another 8 findings that would imply obstacles for surgical cure (invasion of the laryngeal cartilage, invasion of the preepiglottic fat pad, perineural spread, orbital invasion, bone infiltration, skull base invasion, dural infiltration, and invasion of the brachial plexus).
Results: The sensitivity/specificity/accuracy of local resectability-defining factors of PET/CT and PET/MRI was 0.92/0.99/0.98 and 0.98/0.99/0.99 (P = .727), respectively, per lesion, and 0.96/0.87/0.91 and 0.96/0.90/0.93 (P = .687), respectively, per patient.
Conclusion: Both contrast-enhanced PET/MRI and contrast-enhanced PET/CT can serve as reliable examinations for defining local resectability of head and neck cancer.

DOI： 10.1002/hed.24783

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Verlag  

To assess the diagnostic potential of multi-slice single-photon emission computed tomography/computed tomography (SPECT/CT) for preoperative sentinel node (SN) mapping in early stage head and neck squamous cell carcinoma (HNSCC). Retrospective case–control study including data of consecutive HNSCC patients treated between November 2011 and December 2015. The diagnostic accuracy of multi-slice SPECT/CT was assessed with regard to the gold standard intraoperative gamma ray detection probe, using McNemar’s test and calculating the area under the ROC curve. Additionally, the hot spot yield of SPECT/CT and planar lymphoscintigraphy (LS) was compared. Compared to the intraoperative gold standard, SPECT/CT showed an overall positive predictive value of 60.3% [confidence interval (CI) 46.6–73.0%)], a negative predictive value of 96.3% (CI 93.6–98.1%), and an accuracy of 90.8% (CI 89.1–92.4%). SPECT/CT detected more hot spots than LS and provided detailed anatomical information as well as relevant additional findings with potential impact on further patient management. Sentinel lymph node biopsy proved to be a reliable and safe procedure with an excellent SN excision rate (97%). Multi-slice SPECT/CT is a highly accurate diagnostic test and matches the gold standard intraoperative gamma ray detection probe.

DOI： 10.1007/s00405-016-4379-5

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DOI： 10.1177/2058460117701515

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Purpose: To compare the diagnostic accuracy of PET+MR with PET/CT in the initial staging of head and neck cancer.
Materials and methods: Contrast-enhanced PET/CT+MR was performed in 27 patients with newly diagnosed head and neck cancer. PET/CT and PET+MR were evaluated separately, and the TNM stage and factors influencing treatment were assessed.
Results: The TNM staging by PET+MR was comparable to PET/CT (T: p = 0.331, N: p = 0.453, M: p= 0.034). The sensitivity/specificity/accuracy of treatment-influencing factors by PET/CT and PET+MR were 0.68/0.99/0.97, and 1.00/1.00/0.99, respectively.
Conclusions: Whole-body staging with PET+MR yields at least equal diagnostic accuracy as PET/CT in head and neck cancer. (C) 2017 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.clinimag.2017.01.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：LIPPINCOTT WILLIAMS & WILKINS  

Background: To compare the diagnostic accuracy of PET/MR and PET/CT in patients with suspected occult primary tumors.
Methods: This prospective study was approved by the institutional review board. Sequential PET/CT-MR was performed in 43 patients (22 male subjects; median age, 58 years; range, 20-86 years) referred for suspected occult primary tumors. Patients were assessed with PET/CT and PET/MR for the presence of a primary tumor, lymph node metastases, and distant metastases. Wilcoxon signed-rank test was performed to compare the diagnostic accuracy of PET/CT and PET/MR.
Result: According to the standard of reference, a primary lesion was found in 14 patients. In 16 patients, the primary lesion remained occult. In the remaining 13 patients, lesions proved to be benign. PET/MR was superior to PET/CT for primary tumor detection (sensitivity/specificity, 0.85/0.97 vs 0.69/0.73; P = 0.020) and comparable to PET/CT for the detection of lymph node metastases (sensitivity/specificity, 0.93/1.00 vs 0.93/0.93; P = 0.157) and distant metastases (sensitivity/specificity, 1.00/0.97 vs 0.82/1.00; P = 0.564). PET/CT tended to misclassify physiologic FDG uptake as malignancy compared with PET/MR (8 patients vs 1 patient).
Conclusions: PET/MR outperforms PET/CT in the workup of suspected occult malignancies. PET/MR may replace PET/CT to improve clinical workflow.

DOI： 10.1097/RLU.0000000000001461

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：RADIOLOGICAL SOC NORTH AMERICA  

Purpose: To evaluate the magnitude and anatomic extent of the artifacts introduced on positron emission tomographic (PET)/magnetic resonance (MR) images by respiratory state mismatch in the attenuation map.
Materials and Methods: The method was tested on 14 patients referred for an oncologic examination who underwent PET/MR imaging. The acquisition included standard PET and MR series for each patient, and an additional attenuation correction series was acquired by using breath hold. PET data were reconstructed with and without time-of-flight (TOF) information, first by using the standard free-breathing attenuation map and then again by using the additional breath-hold map. Two-tailed paired t testing and linear regression with 0 intercept was performed on TOF versus non-TOF and free-breathing versus breath-hold data for all detected lesions.
Results: Fluorodeoxyglucose-avid lesions were found in eight of the 14 patients included in the study. The uptake differences (maximum standardized uptake values) between PET reconstructions with free-breathing versus breath-hold attenuation ranged, for non-TOF reconstructions, from -18% to 26%. The corresponding TOF reconstructions yielded differences from -15% to 18%.
Conclusion: TOF information was shown to reduce the artifacts caused at PET/MR by respiratory mismatch between emission and attenuation data. (C) RSNA, 2016

DOI： 10.1148/radiol.2016152509

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC NUCLEAR MEDICINE INC  

Accurate attenuation correction (AC) on PET/MR is still challenging. The purpose of this study was to evaluate the clinical feasibility of AC based on fast zero-echo-time (ZTE) MRI by comparing it with the default atlas-based AC on a clinical PET/MR scanner. Methods: We recruited 10 patients with malignant diseases not located on the brain. In all patients, a clinically indicated whole-body F-18-FDG PET/CT scan was acquired. In addition, a head PET/MR scan was obtained voluntarily. For each patient, 2 AC maps were generated from the MR images. One was atlas-AC, derived from T1-weighted liver acquisition with volume acceleration flex images (clinical standard). The other was ZTE-AC, derived from proton-density-weighted ZTE images by applying tissue segmentation and assigning continuous attenuation values to the bone. The AC map generated by PET/CT was used as a silver standard. On the basis of each AC map, PET images were reconstructed from identical raw data on the PET/MR scanner. All PET images were normalized to the SPM5 PET template. After that, these images were qualified visually and quantified in 67 volumes of interest (VOIs; automated anatomic labeling, atlas). Relative differences and absolute relative differences between PET images based on each AC were calculated. F-18-FDG uptake in all 670 VOls and generalized merged VOIs were compared using a paired t test. Results: Qualitative analysis shows that ZTE-AC was robust to patient variability. Nevertheless, misclassification of air and bone in mastoid and nasal areas led to the overestimation of PET in the temporal lobe and cerebellum (%diff of ZTE-AC, 2.46% +/- 1.19% and 3.31% +/- 1.70%, respectively). The vertical bar%diff vertical bar of all 670 VOIs on ZTE was improved by approximately 25% compared with atlas-AC (ZTE-AC vs. atlas-AC, 1.77% +/- 1.41% vs. 2.44% +/- 1.63%, P &lt; 0.01). In 2 of 7 generalized VOIs, vertical bar%diff vertical bar on ZTE-AC was significantly smaller than atlas-AC (ZTE-AC vs. atlas-AC: insula and cingulate, 1.06% +/- 0.67% vs. 2.22% +/- 1.10%, P &lt; 0.01; central structure, 1.03% 0.99% vs. 2.54% 1.20%, P &lt; 0.05). Conclusion: The ZTE-AC could provide more accurate AC than clinical atlas-AC by improving the estimation of head-skull attenuation. The misclassification in mastoid and nasal areas must be addressed to prevent the overestimation of PET in regions near the skull base.

DOI： 10.2967/jnumed.116.175398

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC NUCLEAR MEDICINE INC  

In this work, we assessed the feasibility of attenuation correction (AC) based on a multi-atlas-based method (m-Atlas) by comparing it with a clinical AC method (single-atlas-based method [s-Atlas]), on a time-of-flight (TOF) PET/MRI scanner. Methods: We enrolled 15 patients. The median patient age was 59 y (age range, 31-80). All patients underwent clinically indicated whole-body F-18-FDG PET/CT for staging, restaging, or follow-up of malignant disease. All patients volunteered for an additional PET/MRI scan of the head (no additional tracer being injected). For each patient, 3 AC maps were generated. Both s-Atlas and m-Atlas AC maps were generated from the same patient-specific LAVA-Flex T1-weighted images being acquired by default on the PET/MRI scanner during the first 18 s of the PET scan. An s-Atlas AC map was extracted by the PET/MRI scanner, and an m-Atlas AC map was created using a Web service tool that automatically generates m-Atlas pseudo-CT images. For comparison, the AC map generated by PET/CT was registered and used as a gold standard. PET images were reconstructed from raw data on the TOF PET/MRI scanner using each AC map. All PET images were normalized to the SPM5 PET template, and F-18-FDG accumulation was quantified in 67 volumes of interest (VOIs; automated anatomic labeling atlas). Relative (%diff) and absolute differences (vertical bar%diff vertical bar) between images based on each atlas AC and CT-AC were calculated. F-18-FDG uptake in all VOIs and generalized merged VOIs were compared using the paired t test and Bland-Altman test. Results: The range of error on m-Atlas in all 1,005 VOIs was -4.99% to 4.09%. The vertical bar%diff vertical bar on the m-Atlas was improved by about 20% compared with s-Atlas (s-Atlas vs. m-Atlas: 1.49% +/- 1.06% vs. 1.21% +/- 0.89%, P &lt; 0.01). In generalized VOIs, %diff on m-Atlas in the temporal lobe and cerebellum was significantly smaller (s-Atlas vs. m-Atlas: temporal lobe, 1.49% +/- 1.37% vs. -0.37% +/- 1.41%, P &lt; 0.01; cerebellum, 1.55% +/- 1.97% vs. -1.15% +/- 1.72%, P &lt; 0.01). Conclusion: The errors introduced using either s-Atlas orm-Atlas did not exceed 5% in any brain region investigated. When compared with the clinical s-Atlas, m-Atlas is more accurate, especially in regions close to the skull base.

DOI： 10.2967/jnumed.115.169045

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Our aim was to assess the feasibility of using time-resolved 3D phase-contrast (4D flow) MRI to characterize extracranial-intracranial (EC-IC) bypass.
We enrolled 32 patients who underwent EC-IC bypass (15 men, 17 women; mean age 66.4 years). In all, 16 underwent radial artery graft (RAG) bypass and 16 underwent superficial temporal artery (STA) bypass. 4D flow MRI, time-of-flight (TOF) magnetic resonance angiography (MRA), and computed tomography angiography (CTA) were performed. Bypass patency, flow direction, and blood flow volume (BFV) of each artery were determined by 4D flow MRI. Arterial diameters were measured by TOF-MRA and CTA. We compared RAG and STA bypasses by evaluating the flow direction and BFV of each artery. We evaluated the correlation between arterial diameters (measured by CTA or MRA) and the BFV and the detectability of flow direction (measured by 4D flow MRI) of each artery.
4D flow MRI confirmed the patency of each bypass artery. Flow direction of the M1 segment of the middle cerebral artery and BFV in the bypass artery differed between RAG and STA groups (p &lt; 0.01). BFV in the bypass slightly correlated with the diameters on CTA (p &lt; 0.05, R (2) = 0.287). Of the 29 arteries in the circle of Willis, nine were not depicted on 4D flow MRI. Cutoff values for arterial diameters on CTA and TOF-MRA for detecting the artery on 4D flow MRI were 2.4 and 1.8 mm, respectively.
4D flow MRI provided unique information for characterizing EC-IC bypasses, although this detectability is limited when addressing small arteries with slow flow.

DOI： 10.1007/s00234-015-1626-1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC NUCLEAR MEDICINE INC  

Attenuation correction (AC) for integrated PET/MR imaging in the human brain is still an open problem. In this study, we evaluated a simplified atlas-based AC (Atlas-AC) by comparing F-18-FDG PET data corrected using either Atlas-AC or true CT data (CT-AC). Methods: We enrolled 8 patients (median age, 63 y). All patients underwent clinically indicated whole-body F-18-FDG PET/CT for staging, restaging, or follow-up of malignant disease. All patients volunteered for an additional PET/MR of the head (additional tracer was not injected). For each patient, 2 AC maps were generated: an Atlas-AC map registered to a patient-specific liver accelerated volume acquisition-Flex MR sequence and using a vendor-provided head atlas generated from multiple CT head images and a CT-based AC map. For comparative AC, the CT-AC map generated from PET/CT was superimposed on the Atlas-AC map. PET images were reconstructed from the list-mode raw data from the PET/MR imaging scanner using each AC map. All PET images were normalized to the SPM5 PET template, and F-18-FDG accumulation was quantified in 67 volumes of interest (VOIs; automated anatomic labeling atlas). Relative difference (%diff) between images based on Atlas-AC and CT-AC was calculated, and averaged difference images were generated. F-18-FDG uptake in all VOIs was compared using Bland-Altman analysis. Results: The range of error in all 536 VOIs was -3.0%-7.3%. Whole-brain F-18-FDG uptake based on Atlas-AC was slightly underestimated (%diff = 2.19% +/- 1.40%). The underestimation was most pronounced in the regions below the anterior/posterior commissure line, such as the cerebellum, temporal lobe, and central structures (%diff = 3.69% +/- 1.43%, 3.25% +/- 1.42%, and 3.05% +/- 1.18%), suggesting that Atlas-AC tends to underestimate the attenuation values of the skull base bone. Conclusion: When compared with the gold-standard CT-AC, errors introduced using Atlas-AC did not exceed 8% in any brain region investigated. Underestimation of F-18-FDG uptake was minor (&lt;4%) but significant in regions near the skull base.

DOI： 10.2967/jnumed.115.159228

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

This chapter discusses the staging of mucosal and extramucosal epithelial malignant disease of the head and neck, with the exception of mucosal melanoma and thyroid malignancies.

DOI： 10.1007/978-3-319-30081-8_29

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CANADIAN JOURNAL NEUROLOGICAL SCIENCES INC  

DOI： 10.1017/cjn.2014.6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MEDICAL ASSOC NIPPON MEDICAL SCH  

Acute intracerebral hemorrhage (ICH) associated with mild anemia is commonly observed on radiological examination, and there are several reports of ruptured aneurysms occurring with ICH but without accompanying subarachnoid hemorrhage. However, the relationship among computed tomography (CT), magnetic resonance imaging (MRI), and intraoperative findings of ICH caused by ruptured cerebral aneurysm in patients with severe chronic anemia has been rarely reported and is poorly understood. Here, we report atypical radiological and intraoperative findings of acute ICH caused by ruptured cerebral aneurysm in a patient with severe chronic anemia. A 64-year-old man with anemia was admitted to our hospital after he experienced left hemiparesis and a disturbance of consciousness. At a referring institution, he showed evidence of macrocytic anemia (white blood cell count, 9,000/mu L red blood cell count, 104x10(4)/mu L; hemoglobin, 4.0 g/dL; hematocrit, 12.2%; and platelet count, 26.6x10(4)/mu L). Both CT and MRI showed a right frontal ICH. The outer ring of the hematoma appeared as low-density area on CT, a low-intensity area on T1-weighted MRI, and a high-intensity area on T2-weighted MRI with a serous component. The patient received a blood transfusion and underwent surgical removal of the hematoma the following day. The white serous effusion visualized with CT and MRI was identified as a blood clot in the hematoma cavity. The blood that leaks from blood vessels appears as a high-intensity area on CT because it undergoes plasma absorption in a solidification shrinkage process, and is, therefore, concentrated. Although we did not examine the white effusion to determine if serous components were present, we speculated that the effusion may have contained serous components. Therefore, we removed the part of the effusion that appeared as a low-density area on CT. The presence of ICH without subarachnoid hemorrhage suggested the possible adhesion and rupture of a previous aneurysm. Therefore, ICH appeared as a mixed density area on CT because bleeding may have occurred several times. Because radiological findings of ICH caused by ruptured cerebral aneurysm in patients with severe chronic anemia are similar to those of ICH and cerebral edema, we suggest that the atypical radiological findings of ICH caused by ruptured cerebral aneurysm in patients with severe chronic anemia should be carefully evaluated, especially when surgery is indicated.

DOI： 10.1272/jnms.81.264

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Language：Japanese   Publisher：金原出版(株)  

症例は40歳代女性で、2年前CTで右傍胸椎腫瘤および左副腎腫瘤を指摘され、経過観察された。右傍胸椎腫瘤が増大したため、精査のため受診した。造影CTでTh9レベルの右傍椎体領域に楕円形で17×26×28mm大、境界明瞭な軟部腫瘤を認めた。また左副腎領域や右副腎前方〜腹部大動脈側にも2〜3cm大の腫瘤が散見され、傍胸椎病変と同様の造影所見であった。造影MRIで腫瘤はT1強調像低信号、T2強調像、拡散強調像で高信号を呈し、腫瘤は強い増強効果を示した。FDG-PET/CTで胸椎右側の腫瘤、左副腎、右副腎腹側〜大動脈腹側病変、左傍咽頭領域に高集積腫瘤を認めた。123I-MIBG SPECT/CTで腫瘤の殆どにMIBG高集積が確認されたが腹部大動脈腹側病変の一部や脾臓病変では集積を認めなかった。MIBG強陽性を呈した左副腎領域病変に対し腹腔鏡下左副腎切除術が施行された。腫瘤組織は類円形〜やや紡錘形の核を有する細胞が小型胞巣を形成しながら索状あるいは密に増生し有糸核分裂は目立たず、出血・壊死は認めなかった。S-100、シナプトフィシン、クロモグラニンAは陽性で、副腎外褐色細胞腫と診断された。

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE  

Purpose: A drawback of time-resolved 3-dimensional phase contrast magnetic resonance (4D Flow MR) imaging is its lengthy scan time for clinical application in the brain. We assessed the feasibility for flow measurement and visualization of 4D Flow MR imaging using Cartesian y-z radial sampling and that using k-t sensitivity encoding (k-t SENSE) by comparison with the standard scan using SENSE.
Materials and Methods: Sixteen volunteers underwent 3 types of 4D Flow MR imaging of the brain using a 3.0-tesla scanner. As the standard scan, 4D Flow MR imaging with SENSE was performed first and then followed by 2 types of acceleration scan with Cartesian y-z radial sampling and with k-t SENSE. We measured peak systolic velocity (PSV) and blood flow volume (BFV) in 9 arteries, and the percentage of particles arriving from the emitter plane at the target plane in 3 arteries, visually graded image quality in 9 arteries, and compared these quantitative and visual data between the standard scan and each acceleration scan.
Results: 4D Flow MR imaging examinations were completed in all but one volunteer, who did not undergo the last examination because of headache. Each acceleration scan reduced scan time by 50% compared with the standard scan. The k-t SENSE imaging underestimated PSV and BFV (P &lt; 0.05). There were significant correlations for PSV and BFV between the standard scan and each acceleration scan (P &lt; 0.01). The percentage of particles reaching the target plane did not differ between the standard scan and each acceleration scan. For visual assessment, y-z radial sampling deteriorated the image quality of the 3 arteries.
Conclusion: Cartesian y-z radial sampling is feasible for measuring flow, and k-t SENSE offers sufficient flow visualization; both allow acquisition of 4D Flow MR imaging with shorter scan time.

DOI： 10.2463/mrms.2013-0008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：HINDAWI PUBLISHING CORPORATION  

Purpose. To investigate the liver volume change and the potential of early evaluation by contrast-enhanced magnetic resonance imaging (MRI) using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) after portal vein embolization (PVE). Materials and Methods. Retrospective evaluations of computed tomography (CT) volumetry of total liver and nonembolized areas were performed before and 3 weeks after PVE in 37 cases. The percentage of future liver remnant (%FLR) and the change ratio of %FLR (%FLR ratio) were calculated. Prospective evaluation of signal intensities (SIs) was performed to estimate the role of Gd-EOB-DTPA-enhanced MRI as a predictor of hypertrophy in 16 cases. The SI contrast between embolized and nonembolized areas was calculated 1 week after PVE. The change in SI contrast before and after PVE (SI ratio) was also calculated in 11 cases. Results. %FLR ratio significantly increased, and SI ratio significantly decreased (both P &lt; 0.01). There were significant negative correlations between %FLR and SI contrast and between %FLR and SI ratio (both P &lt; 0.01). Conclusion. Hypertrophy in the nonembolized area after PVE was indicated by CT volumetry, and measurement of SI contrast and SI ratio in Gd-EOB-DTPA-enhanced MRI early after PVE may be useful to predict the potential for hepatic hypertrophy.

DOI： 10.1155/2014/684754

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DOI： 10.1016/j.clineuro.2013.05.022

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DOI： 10.1272/jnms.80.2

PubMed

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Language：English   Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE  

Sarcoidosis is a multisystem disorder of unknown etiology that involves multiple organs. Computed tomography is the first-line imaging modality for diagnosing sarcoidosis because of its capacity to detect hilar lymphadenopathy and pulmonary lesions. Magnetic resonance (MR) imaging provides good soft tissue contrast that is useful for detecting sarcoidosis in some body parts, including skeletal muscle. Signal intensity on pre- and post-contrast T-1- and T-2-weighted imaging may reflect disease activity and the pathological appearance of sarcoidosis. In this review, we demonstrate these conventional MR imaging findings of hepatosplenic and muscular sarcoidosis and describe the usefulness of diffusion-weighted imaging for detecting sarcoidosis.

DOI： 10.2463/mrms.11.83

Web of Science

PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JPN SOC MAGNETIC RESONANCE IN MEDICINE  

Purpose: The blood flow patterns of chronic thoracic aortic dissection are complicated, and their clinical significance remains unknown. We evaluated the technical and clinical potentials of time-resolved 3-dimensional (3D) magnetic resonance (MR) velocity mapping for assessing these patterns.
Methods: We used data collected from time-resolved 3D phase-contrast MR imaging of 16 patients with chronic thoracic aortic dissection to generate time-resolved 3D MR velocity mapping that included 3D streamline and path line. We investigated blood flow patterns of this disease in the mapping and compared them with the morphological changes of the patent false lumen.
Results: Time-resolved 3D MR velocity mapping visualized rapid flow at the entry and in the true lumen immediately distal to the entry. We observed slower helical or laminar flow in the patent false lumen. In patients with disease progression, slower helical flow following rapid entry jet collided with the outer wall of the false lumen and was also observed in a growing ulcer-like projection.
Conclusion: We showed the potential of time-resolved 3D MR velocity mapping for visualizing pathologic flow patterns related to chronic thoracic aortic dissection.

DOI： 10.2463/mrms.10.93

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PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Takayasu arteritis is an inflammatory disease of unknown etiology that involves the aorta, its major branches, and the pulmonary artery. We describe three patients with Takayasu arteritis who showed abnormal velocity profile of the thoracic aorta and supra-aortic arteries on time-resolved three-dimensional (3D) phase-contrast MR imaging and velocity mapping techniques. Compared with two comparative subjects, velocity reduction was observed in these arteries. The velocity reduction was prominent along the thickened arterial wall, even with normal luminal caliber, and the highest velocity was observed on the contralateral side. In one patient, the arterial flow velocity and its profile at systole were partly improved after the treatment. The time-resolved 3D velocity mapping visualized the changes in the blood velocity profile at systole in Takayasu arteritis.

DOI： 10.1002/jmri.22007

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PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Lanthanum carbonate hydrate is a nonaluminum, noncalcium phosphate binder containing lanthanum (La). It is effective in decreasing the serum phosphate level in patients on dialysis. Because the atomic number of the La contained in lanthanum carbonate hydrate is relatively high, at 57, this agent may cause strong artifacts on computed tomography (CT) images, which may be mistakenly interpreted as foreign bodies. We recently performed CT examination of a patient on Fosrenol chewable tablets (i.e., lanthanum carbonate hydrate). The CT images were difficult to evaluate because of strong beam hardening artifacts, and differentiation from foreign body aspiration was required. We report here our experience and a discussion of the characteristics of this artifact.

DOI： 10.1007/s11604-010-0426-0

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Language：English   Publishing type：Research paper (scientific journal)  

Lanthanum carbonate hydrate is a nonaluminum, noncalcium phosphate binder containing lanthanum (La). It is effective in decreasing the serum phosphate level in patients on dialysis. Because the atomic number of the La contained in lanthanum carbonate hydrate is relatively high, at 57, this agent may cause strong artifacts on computed tomography (CT) images, which may be mistakenly interpreted as foreign bodies. We recently performed CT examination of a patient on Fosrenol chewable tablets (i.e., lanthanum carbonate hydrate). The CT images were difficult to evaluate because of strong beam hardening artifacts, and differentiation from foreign body aspiration was required. We report here our experience and a discussion of the characteristics of this artifact. © 2010 Japan Radiological Society.

DOI： 10.1007/s11604-010-0426-0

Scopus

PubMed

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Language：English   Publishing type：Research paper (scientific journal)  

For diagnosis of pulmonary thromboembolism, multidetector-row computed tomography (CT) is a minimally invasive imaging technique that can be performed rapidly with high sensitivity and specificity, and has been increasingly employed as the imaging modality of first choice for this disease. Since deep vein thrombosis in the legs, which is important as a thrombus source, can be evaluated immediately after the diagnosis of pulmonary thromboembolism, this diagnostic method is considered to provide important information when deciding on a comprehensive therapeutic strategy for this disease.

DOI： 10.3400/avd.sasdi10005

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Language：Japanese   Publisher：日本医科大学医学会  

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Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2021&ichushi_jid=J04260&link_issn=&doc_id=20211116290030&doc_link_id=%2Fcw1nimed%2F2021%2Fu01704%2F015%2F0235-0236%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcw1nimed%2F2021%2Fu01704%2F015%2F0235-0236%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(株)中外医学社  

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File： JCRニュース238号_私の留学記_関根.pdf

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Language：Japanese   Publisher：(株)インナービジョン  

4D Flow MRIは長らく研究シーケンスとされており、限られた施設からの報告のみであった。しかし、ここ数年で撮像・解析が劇的に容易となってきている。その一方、4D Flow MRIの臨床的意義づけについては方向性が定まっていない。撮像・解析項目に多様な選択肢が存在するが、その中から何を適切に選択すべきかについての指標が欠けている状態である。このため、初学者にはとっつきにくい領域になっている。本稿では、4D Flow MRIを取り巻く現況と今後の方向性について概説する。本稿が、これから同撮像を行う初学者へのfirst stepとなることをめざして執筆した。読了後に、新規に4D Flow MRIを開始する施設が1施設でも増えれば、筆者の試みは成功と考える。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

4Dーflow MRIは頭頸部領域の複雑な血流パターンの測定,視覚化が可能である。現在,頭頸部領域では研究目的に撮像されていることがほとんどであるが,高速化撮像法により撮像時間が短縮され,さまざまな頭蓋内病変への検査の有用性が報告されてきたことで,臨床応用への期待が高まっている。本稿では,撮像法の発展,筆者らの経験,過去の研究報告や今後の臨床応用の可能性について述べる。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2020&ichushi_jid=J01843&link_issn=&doc_id=20200107200002&doc_link_id=10.18885%2FCI.0000000103&url=https%3A%2F%2Fdoi.org%2F10.18885%2FCI.0000000103&type=%88%E3%8F%91.jp_%83I%81%5B%83%8B%83A%83N%83Z%83X&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：(一社)日本磁気共鳴医学会  

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J-GLOBAL

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Language：Japanese   Publisher：産業開発機構(株)  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2018&ichushi_jid=J00116&link_issn=&doc_id=20190107300002&doc_link_id=%2Fan7eizoc%2F2018%2F005014%2F007%2F0030-0067%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fan7eizoc%2F2018%2F005014%2F007%2F0030-0067%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(一社)日本神経学会  

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Language：Japanese   Publisher：(一社)日本頭頸部癌学会  

本稿では、2018年度の頭頸部癌学会において開催されたシンポジウム&quot;頭頸部癌における画像診断の進歩と今後の展望&quot;内の&quot;PET/CTの最近の知見とPET/MR&quot;で講演した内容につき、(1)頭頸部癌化学放射線治療後の残存・再発腫瘍評価におけるFDG-PET/CT撮影の役割、(2)PET/CT定量指標とHarmonization、(3)腫瘍不均一性とTexture analysis、(4)PET/MRの頭頸部癌診療における役割の4点について、述べる。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞頭部外傷の際に骨盤や四肢の長管骨骨折を合併した患者の場合、脂肪塞栓(cerebral fat embolism)との鑑別が問題となる。病変信号自体は類似するが、出血を伴う点[DAIは一部病変(4割)に出血を伴う]や分布が異なる点(脂肪塞栓の病変は深部白質や小脳にも認められるなど)、全身症状(皮膚や結膜の点状出血、急激に進行する呼吸困難)などから鑑別が可能である3)。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞突然の背部痛に続き、体幹部の神経学的症状が出現した際は、脊髄硬膜外血腫も鑑別に挙げて積極的に脊柱管内の検索を行うことが重要である。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2018&ichushi_jid=J01843&link_issn=&doc_id=20181009050031&doc_link_id=10.18885%2FJ01843.2019006642&url=https%3A%2F%2Fdoi.org%2F10.18885%2FJ01843.2019006642&type=%88%E3%8F%91.jp_%83I%81%5B%83%8B%83A%83N%83Z%83X&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞高齢化により、軽度の転倒による脊髄損傷が増加している3)。MRIで脊髄の浮腫性変化や出血を丁寧に評価することが重要である。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2018&ichushi_jid=J01843&link_issn=&doc_id=20181009050029&doc_link_id=10.18885%2FJ01843.2019006640&url=https%3A%2F%2Fdoi.org%2F10.18885%2FJ01843.2019006640&type=%88%E3%8F%91.jp_%83I%81%5B%83%8B%83A%83N%83Z%83X&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞神経根の直接評価はMRI、CTともに、アーチファクトの影響もあり、困難なことも少なくない。偽性髄膜瘤や筋の脱神経所見も併せて、損傷部位、高位を推定する。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞出血を伴わない深部灰白質損傷はCTで描出されないことが多い。ときに出血巣が主体で周囲脳浮腫が目立たない場合、CTのみの診断ではあたかも&quot;外傷に合併した高血圧性脳出血&quot;様に描出される。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞脳幹損傷は複数の機序で生じ、発症機序により予後も異なる。脳幹内の病変の局在、テント上に合併した病変の有無などと組み合わせて正確な診断を行う。(著者抄録)

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Language：Japanese   Publisher：(株)メジカルビュー社  

＜診断のポイント＞小さな血腫を伴ったびまん性軸索損傷、外傷に伴った血管損傷に起因する梗塞巣、限局性の脳表のクモ膜下出血、ほかの病態に起因する脳外傷周囲の脳腫脹などは、脳挫傷とは損傷の病態生理が異なる点に留意する。(著者抄録)

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Language：Japanese   Publisher：(株)インナービジョン  

近年、心血管領域における4D Flow MRIを用いた流体解析が注目を浴びている。4D Flow MRI自体は2000年代前半から研究報告がなされ、おおよそのシーケンスは2010年頃に完成し、近年、撮像に関するconsensus statementsも発表された。いまだ研究用途の色合いが強い撮像法ではあるが、心大血管の流体解析において、新規のimaging biomarkerを提供できると期待されている。本稿では、項目を絞って、(1)撮像の高速化、(2)速度分解能の向上、(3)流体力学的解析手法の発展、(4)乱流運動エネルギー(turbulent kinetic energy:TKE)定量の4つのキーワードを中心に概説する。(著者抄録)

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：(株)羊土社  

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J-GLOBAL

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：日本医科大学医学会  

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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J-GLOBAL

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Language：Japanese   Publisher：放射線診療研究会  

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Language：Japanese   Publisher：(有)科学評論社  

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J-GLOBAL

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Language：Japanese   Publisher：(株)羊土社  

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Language：Japanese   Publisher：日本医科大学医学会  

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

DOI： 10.15105/J00235.2016320506

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SOC NUCLEAR MEDICINE INC  

Web of Science

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SOC NUCLEAR MEDICINE INC  

Web of Science

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SOC NUCLEAR MEDICINE INC  

Web of Science

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

DOI： 10.15105/J00235.2014056716

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Language：Japanese   Publisher：(株)メジカルビュー社  

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J-GLOBAL

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

J-GLOBAL

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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J-GLOBAL

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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J-GLOBAL

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Language：Japanese   Publisher：(株)学研メディカル秀潤社  

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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Language：Japanese   Publisher：バイエル薬品(株)  

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Language：English   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)   Publisher：JOHN WILEY & SONS INC  

DOI： 10.1002/jmri.22401

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Language：Japanese   Publisher：(公社)日本医学放射線学会  

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Language：English   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)  

DOI： 10.1002/jmri.22401

Scopus

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Language：Japanese   Publisher：(一社)日本脈管学会  

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Language：English   Presentation type：Symposium, workshop panel (nominated)  

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