Silverman P M, Patt R H, Garra B S, Horii S C, Cooper C, Hayes W S, Zeman R K
Department of Radiology, Georgetown University Hospital, Washington, DC 20007.
AJR Am J Roentgenol. 1991 Aug;157(2):297-302. doi: 10.2214/ajr.157.2.1853810.
We evaluated the use of gradient-echo (GRE) as an adjunct to spin-echo (SE) MR imaging of the portal venous system. GRE imaging was performed in 31 subjects, 15 normal volunteers and 16 patients with documented portal venous disease (15 cases) or suspected disease (one case). Eight of 16 patients had venous thrombosis, five had focal thrombus, and three had complete occlusion. Six patients had extrinsic venous compression by tumor. Of the two other patients, one had an arteriovenous fistula and the other a falsely positive angiogram, suggesting portal vein occlusion. In normal subjects, GRE scans had excellent visualization of the portal venous system with high intravascular signal compared with surrounding tissues. Nine (60%) of 15 normal subjects and three patients had an artifact consisting of a curvilinear area of decreased signal that could mimic clot. In three of five patients with focal thrombus, clot was identified on GRE but not on SE images. In all three patients with occlusion, SE and GRE images demonstrated similar findings. In five of the six patients with extrinsic venous compression by tumor, SE and GRE studies showed similar findings. Of the two patients, an arteriovenous fistula was seen on GRE MR in one, and in the other, patency of the left portal vein was seen on SE and GRE images after angiography had suggested portal vein occlusion. Collateral vessels were seen in nine of 16 patients. In five of nine cases, GRE MR demonstrated more extensive collaterals than did SE MR. In summary, GRE MR provides a useful adjunct to standard SE MR imaging. Benefits include high contrast between vascular structures and surrounding tissues, reduced motion artifact, and rapid scanning within a breath-hold.
我们评估了梯度回波（GRE）作为门静脉系统自旋回波（SE）磁共振成像辅助手段的应用。对31名受试者进行了GRE成像，其中包括15名正常志愿者以及16名有门静脉疾病记录（15例）或疑似疾病（1例）的患者。16名患者中，8例有静脉血栓形成，5例有局灶性血栓，3例完全闭塞。6例患者存在肿瘤对静脉的外在压迫。另外两名患者中，1例有动静脉瘘，另1例血管造影显示门静脉闭塞为假阳性。在正常受试者中，GRE扫描能很好地显示门静脉系统，血管内信号高于周围组织。15名正常受试者中有9名（60%）以及3名患者存在一种伪影，表现为信号降低的曲线形区域，可模拟血栓。在5例局灶性血栓患者中的3例，GRE图像上能识别出血栓，而SE图像上则不能。在所有3例闭塞患者中，SE和GRE图像显示的结果相似。在6例因肿瘤导致静脉外在压迫的患者中的5例，SE和GRE检查结果相似。在这两名患者中，1例在GRE磁共振成像上可见动静脉瘘，另1例在血管造影提示门静脉闭塞后，SE和GRE图像显示左门静脉通畅。16例患者中有9例可见侧支血管。在9例中的5例，GRE磁共振成像显示的侧支血管比SE磁共振成像更广泛。总之，GRE磁共振成像为标准的SE磁共振成像提供了一种有用的辅助手段。其优点包括血管结构与周围组织之间的高对比度、减少运动伪影以及屏气状态下的快速扫描。
