Nagao Michinobu, Yamasaki Yuzo, Abe Kohtaro, Hosokawa Kazuya, Kawanami Satoshi, Kamitani Takeshi, Yamanouchi Torahiko, Yabuuchi Hidetake, Fukushima Kenji, Honda Hiroshi
Department of Diagnostic Imaging & Nuclear Medicine, Tokyo Women's Medical University, Tokyo, Japan.
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Eur J Radiol. 2017 Feb;87:99-104. doi: 10.1016/j.ejrad.2016.12.015. Epub 2016 Dec 16.
The aims of this study were to propose a new quantitative method for pulmonary artery (PA) flow energetics using phase-contrast magnetic resonance imaging (PC-MRI), and to investigate how balloon pulmonary angioplasty (BPA) impacts energetics in chronic thromboembolic pulmonary hypertension (CTEPH).
PC-MRI at 3-Teslar and with a flow sensitive gradient echo was used to examine energetics prior to and following BPA for 24 CTEPH patients. Stroke volume (m; ml) and mean velocity (V; mm/s) for the main pulmonary artery (PA), right PA, and left PA were calculated from a time-flow curve derived from PC-MRI. Based on the Bernoulli principle, PA energy was identified as 1/2mV (μj/kg), and energy loss was defined as the following equation "energy loss=main PA energy-(rt. PA energy+lt. PA energy)".
Right PA energy was significantly greater post-BPA than pre-BPA (61±55 vs. 32±40μj/kg). There was no difference in main PA and left PA energies. Energy loss was significantly decreased post-BPA (18±97μj/kg) than pre-BPA (79±125μj/kg). An optimal cutoff of left PA energy of 45μj/kg pre-BPA can be used to predict patients with mPAP≥30mmHg after BPA, with an area under the curve of 0.91, 78% sensitivity, and 92% specificity.
Analysis of PA energetics using phase-contrast MRI demonstrates that BPA improves energy loss in CTEPH. In addition, BPA responses can be predicted by PA energy status pre-treatment.
本研究的目的是提出一种使用相位对比磁共振成像（PC-MRI）定量分析肺动脉（PA）血流能量学的新方法，并研究球囊肺动脉血管成形术（BPA）如何影响慢性血栓栓塞性肺动脉高压（CTEPH）患者的能量学变化。
对24例CTEPH患者在3特斯拉场强下采用血流敏感梯度回波序列的PC-MRI，分别在BPA术前和术后检测能量学变化。从PC-MRI获得的时间-血流曲线计算主肺动脉（PA）、右肺动脉和左肺动脉的每搏输出量（m；ml）和平均流速（V；mm/s）。基于伯努利原理，PA能量定义为1/2mV（μj/kg），能量损失定义为以下公式“能量损失=主PA能量-（右PA能量+左PA能量）”。
BPA术后右PA能量显著高于术前（61±55 vs. 32±40μj/kg）。主PA和左PA能量无差异。BPA术后能量损失显著低于术前（18±97μj/kg vs. 79±125μj/kg）。术前左PA能量的最佳截断值为45μj/kg，可用于预测BPA术后平均肺动脉压（mPAP）≥30mmHg的患者，曲线下面积为0.91，敏感度为78%，特异度为92%。
使用相位对比MRI分析PA能量学表明，BPA可改善CTEPH患者的能量损失。此外，BPA反应可通过术前PA能量状态进行预测。
