Second Department of Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Department of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University, Graduate School of Medicine, Nagoya, Japan.
J Vasc Surg. 2019 Jul;70(1):107-116.e1. doi: 10.1016/j.jvs.2018.09.048. Epub 2019 Feb 18.
The objective of this study was to investigate the hemodynamic parameters of type II endoleaks (T2ELs) to predict sac expansion using four-dimensional flow-sensitive magnetic resonance imaging (4D-flow MRI) analysis.
Patients who underwent endovascular aneurysm repair (EVAR) and were diagnosed with a T2EL were included in the study. Using 4D-flow MRI at 7 days, the peak flow velocity and amplitude of dynamics of blood flow per minute were measured in each T2EL vessel. The peak flow velocity was defined as the maximum of the absolute value of the blood flow velocity. The amplitude of dynamics of blood flow in the tributary arteries was defined as the sum of the absolute values of the inflow and outflow volume in each vessel. The amplitude of dynamics of blood flow in the tributary arteries per sac was calculated in each sac. The aneurysm sac diameter was measured by computed tomography (CT) at 1 year. The patients were divided into two groups according to the presence or absence of sac expansion.
Of 155 patients who underwent EVAR, both CT angiography and 4D-flow MRI were performed in 107 patients at 7 days after EVAR. Among them, 39 (36.4%) were found to have a T2EL, of whom 28 were re-evaluated with CT angiography and 4D-flow at 1 year; 7 patients had expanding sacs (expanding group), whereas 21 had nonexpanding sacs (not-expanding group). At 7 days, 28 patients had 80 T2EL vessels detected by 4D-flow MRI, of which 39 vessels (48.8%) had stopped flowing at 1 year (transient vessels); 41 vessels (51.3%) had sustained flow (persistent vessels). The persistent vessels had significantly larger peak flow velocity and amplitude of dynamics of blood flow. The comprehensive analysis of T2EL vessels per sac identified that the amplitude of dynamics of blood flow in the tributary arteries per sac was significantly higher in the expanding group than in the not-expanding group. A receiver operating characteristic curve analysis revealed that the sensitivity and specificity of sac enlargement at a cutoff value of 3750 mm/min were 85.7% and 76.2%, respectively.
The fate of aneurysm sacs with T2ELs after EVAR has remained difficult to predict. A comprehensive analysis of concurrent multiple T2EL vessels using 4D-flow MRI analysis may enable prediction of the sac expansion after EVAR.
本研究旨在通过四维血流敏感磁共振成像（4D-flow MRI）分析，探讨 II 型内漏（T2EL）的血流动力学参数，以预测瘤囊扩张。
本研究纳入了接受血管内动脉瘤修复（EVAR）并诊断为 T2EL 的患者。在术后 7 天使用 4D-flow MRI，测量每个 T2EL 血管的峰值血流速度和每分钟血流动力学振幅。峰值血流速度定义为血流速度绝对值的最大值。分支动脉血流动力学振幅定义为每个血管内流入和流出量绝对值之和。计算每个瘤囊内分支动脉血流动力学振幅。通过计算机断层扫描（CT）在术后 1 年测量瘤囊直径。根据瘤囊是否扩张将患者分为两组。
在 155 例行 EVAR 的患者中，107 例行 EVAR 后 7 天行 CT 血管造影和 4D-flow MRI 检查。其中，39 例（36.4%）被发现存在 T2EL，其中 28 例在 1 年后行 CT 血管造影和 4D-flow 再评估；7 例瘤囊扩张（扩张组），21 例瘤囊无扩张（未扩张组）。在术后 7 天，4D-flow MRI 检测到 28 例患者的 80 个 T2EL 血管，其中 39 个血管（48.8%）在 1 年后停止血流（一过性血管）；41 个血管（51.3%）持续血流（持续性血管）。持续性血管的峰值血流速度和血流动力学振幅明显更大。对每个瘤囊的 T2EL 血管进行综合分析，发现扩张组的分支动脉血流动力学振幅明显高于未扩张组。受试者工作特征曲线分析显示，当截断值为 3750mm/min 时，预测瘤囊扩张的敏感性和特异性分别为 85.7%和 76.2%。
EVAR 后 T2EL 瘤囊的命运仍然难以预测。使用 4D-flow MRI 分析对并发的多个 T2EL 血管进行综合分析，可能有助于预测 EVAR 后瘤囊的扩张。
