Lee Cheng-Chia, Reardon Michael A, Ball Benjamin Z, Chen Ching-Jen, Yen Chun-Po, Xu Zhiyuan, Wintermark Max, Sheehan Jason
Departments of 1 Neurological Surgery.
Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital;
J Neurosurg. 2015 Jul;123(1):136-44. doi: 10.3171/2014.10.JNS141565. Epub 2015 Apr 3.
The current gold standard for diagnosing arteriovenous malformation (AVM) and assessing its obliteration after stereotactic radiosurgery (SRS) is digital subtraction angiography (DSA). Recently, MRI and MR angiography (MRA) have become increasingly popular imaging modalities for the follow-up of patients with an AVM because of their convenient setup and noninvasiveness. In this study, the authors assessed the sensitivity and specificity of MRI/MRA in evaluating AVM nidus obliteration as assessed by DSA.
The authors study a consecutive series of 136 patients who underwent SRS between January 2000 and December 2012 and who underwent regular clinical examinations, several MRI studies, and at least 1 post-SRS DSA follow- up evaluation at the University of Virginia. The average follow-up time was 47.3 months (range 10.1-165.2 months). Two blinded observers were enrolled to interpret the results of MRI/MRA compared with those of DSA. The sensitivity, specificity, positive predictive value, and negative predictive value for the obliteration of AVM were reported.
On the basis of DSA, 73 patients (53.7%) achieved final angiographic obliteration in a median of 28.8 months. The sensitivity (the probability of finding obliteration on MRI/MRA among those for whom complete obliteration was shown on DSA) was 84.9% for one observer (Observer 1) and 76.7% for the other (Observer 2). The specificity was 88.9% and 95.2%, respectively. The false-negative interpretations were significantly related to the presence of draining veins, perinidal edema on T2-weighted images, and the interval between the MRI/MRA and DSA studies.
MRI/MRA predicted AVM obliteration after SRS in most patients and can be used in their follow-up. However, because the specificity of MRI/MRA is not perfect, DSA should still be performed to confirm AVM nidus obliteration after SRS.
目前诊断动静脉畸形（AVM）并评估其立体定向放射外科治疗（SRS）后闭塞情况的金标准是数字减影血管造影（DSA）。近来，由于其设置便捷且无创，MRI和磁共振血管造影（MRA）已成为AVM患者随访中越来越常用的成像方式。在本研究中，作者评估了MRI/MRA在评估经DSA判定的AVM病灶闭塞情况时的敏感性和特异性。
作者研究了2000年1月至2012年12月期间在弗吉尼亚大学连续接受SRS治疗并进行定期临床检查、多次MRI检查以及至少1次SRS后DSA随访评估的136例患者。平均随访时间为47.3个月（范围10.1 - 165.2个月）。招募两名盲法观察者解读MRI/MRA与DSA的结果对比。报告了AVM闭塞的敏感性、特异性、阳性预测值和阴性预测值。
基于DSA，73例患者（53.7%）在中位时间28.8个月时实现了最终血管造影闭塞。一名观察者（观察者1）的敏感性（在DSA显示完全闭塞的患者中，在MRI/MRA上发现闭塞的概率）为84.9%，另一名观察者（观察者2）为76.7%。特异性分别为88.9%和95.2%。假阴性解读与引流静脉的存在、T2加权图像上的病灶周围水肿以及MRI/MRA和DSA检查之间的时间间隔显著相关。
MRI/MRA可预测大多数患者SRS后AVM的闭塞情况，并可用于其随访。然而，由于MRI/MRA的特异性并不完美，SRS后仍应进行DSA以确认AVM病灶闭塞情况。
