Department of Radiology/Image Sciences Institute, University Medical Center, Utrecht, The Netherlands.
J Vasc Surg. 2012 Oct;56(4):938-42. doi: 10.1016/j.jvs.2012.03.015. Epub 2012 May 15.
During endovascular abdominal aortic aneurysm repair (EVAR), blood is trapped in the aneurysm sac at the moment the endograft is deployed. It is generally assumed that this blood will coagulate and evolve into an organized thrombus. It is unknown whether this process always occurs, what its time span is, and how it influences aneurysm shrinkage. With magnetic resonance imaging (MRI), quantitative analysis of the aneurysm sac is possible in terms of endoleak volume as well as unorganized thrombus volume and organized thrombus volume. We investigated the presence of unorganized thrombus in nonshrinking aneurysms years after EVAR.
Fourteen patients with a nonshrinking aneurysm without endoleak on computed tomography/computed tomography angiography underwent MRI with a blood pool agent (gadofosveset trisodium). Precontrast T1-, precontrast T2-, and postcontrast T1-weighted images (3 and 30 minutes after injection) were acquired and evaluated for the presence of endoleak. The aneurysm sac was segmented into endoleak, unorganized thrombus, and organized thrombus by interactively thresholding the differently weighted images. The classification was visualized in real-time as a color overlay on the MR images. The volumes of endoleak, unorganized thrombus, and organized thrombus were calculated.
Median time after EVAR was 2 years (range, 1-8.2 years). The average aneurysm sac volume of the patients was 167 ± 107 mL (mean ± standard deviation). Nine patients had an endoleak on the postcontrast T1-w images 30 minutes after injection. On average, the aneurysm sac contained 78 ± 61 mL unorganized thrombus, which corresponded to 51 ± 21 volume-percentage, irrespective of the presence of an endoleak on the blood pool agent enhanced MRI images (independent t-test, P = .8).
In our study group, half of the nonshrinking aneurysm sac contents consisted of unorganized thrombus years after EVAR.
在血管内腹主动脉瘤修复（EVAR）过程中，覆膜支架植入时，血液被困在动脉瘤囊中。一般认为，这些血液会凝固并演变成有组织的血栓。目前尚不清楚这个过程是否总是发生，其时间跨度是多少，以及它如何影响动脉瘤的缩小。通过磁共振成像（MRI），可以对动脉瘤囊进行定量分析，包括内漏量、无组织血栓量和有组织血栓量。我们研究了 EVAR 多年后无缩小的动脉瘤中无组织血栓的存在情况。
14 名无内漏的非缩小性动脉瘤患者在 CT/CT 血管造影后接受 MRI 检查，使用血池造影剂（钆喷酸葡胺三钠）。采集并评估预对比 T1 加权像、预对比 T2 加权像和对比后 T1 加权像（注射后 3 分钟和 30 分钟），以评估内漏的存在情况。通过对不同加权图像进行交互阈值处理，将动脉瘤囊分为内漏、无组织血栓和有组织血栓。分类以实时彩色叠加的方式显示在 MR 图像上。计算内漏、无组织血栓和有组织血栓的体积。
EVAR 后中位时间为 2 年（范围 1-8.2 年）。患者的平均动脉瘤囊体积为 167±107mL（均值±标准差）。9 名患者在注射后 30 分钟的对比后 T1-w 图像上存在内漏。平均而言，动脉瘤囊中含有 78±61mL 的无组织血栓，占 51±21%的体积百分比，与血池造影剂增强 MRI 图像上是否存在内漏无关（独立 t 检验，P=0.8）。
在我们的研究组中，EVAR 多年后，一半的非缩小性动脉瘤囊内容物为无组织血栓。
