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

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   Publishing type：Research paper (scientific journal)  

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

DOI： 10.21037/jtd-20-3229

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

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：English   Publishing type：Research paper (scientific journal)  

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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Language：Japanese   Publisher：(一社)日本呼吸器外科学会  

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Language：Japanese   Publisher：(NPO)日本肺癌学会  

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

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Other Link： https://search.jamas.or.jp/default/link?pub_year=2020&ichushi_jid=J02090&link_issn=&doc_id=20200319090009&doc_link_id=10.2463%2Fjjmrm.2019-1700&url=https%3A%2F%2Fdoi.org%2F10.2463%2Fjjmrm.2019-1700&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_3.gif

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

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