Babiarz L S, Romero J M, Murphy E K, Brobeck B, Schaefer P W, González R G, Lev M H
Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass. 02114, USA.
AJNR Am J Neuroradiol. 2009 Apr;30(4):761-8. doi: 10.3174/ajnr.A1464. Epub 2009 Jan 22.
Internal carotid artery (ICA) atheromatous disease is an important cause of ischemic stroke, and endarterectomy or stent placement is typically indicated for symptomatic patients with > or = 70% stenosis. Our purpose was to compare contrast-enhanced MR angiography (CE-MRA) with unenhanced 2D time-of-flight MR angiography (2D TOF MRA) in detecting hemodynamically significant ICA stenosis, by using CT angiography (CTA) as the reference standard.
This was an institutional review board-approved retrospective study. We identified 177 consecutive patients (354 ICAs) who received correlative CE-MRA, 2D TOF MRA, and CTA. Two neuroradiologists blinded to the CTA data graded the degree of ICA stenosis according to a 5-point scale. Additionally, luminal signal-intensity characteristics including 1) signal intensity drop-out, 2) distal-vessel narrowing, and 3) distal-vessel signal-intensity reduction were recorded. MRA results were correlated with those of CTA, and receiver-operating-characteristic (ROC) curves were constructed.
On CTA, there were 55 ICAs with and 299 without > or = 70% stenosis. CE-MRA was 84% sensitive and 96% specific for detecting > or = 70% stenosis; 2D TOF MRA was 80% sensitive and 95% specific. The area under the ROC curve was 0.97 for CE-MRA and 0.95 for 2D TOF MRA (P = .51, not significant). For both MRA studies, each of the luminal signal-intensity characteristics had high specificity (> 98%) but poor-to-mild sensitivity (35%-66%) in detecting > or = 70% stenosis.
Although it is established that CE-MRA more accurately delineates neurovascular anatomy than does unenhanced 2D TOF MRA, the administration of gadolinium did not offer a significant advantage in distinguishing surgically treatable ICA stenosis. This conclusion may be important in patients with contraindications to gadolinium.
颈内动脉（ICA）粥样硬化性疾病是缺血性卒中的重要病因，对于症状性狭窄≥70%的患者，通常建议行内膜切除术或支架置入术。我们的目的是通过使用CT血管造影（CTA）作为参考标准，比较对比增强磁共振血管造影（CE-MRA）与非增强二维时间飞跃磁共振血管造影（2D TOF MRA）在检测具有血流动力学意义的ICA狭窄方面的差异。
这是一项经机构审查委员会批准的回顾性研究。我们纳入了177例连续患者（354条ICA），他们均接受了相关的CE-MRA、2D TOF MRA和CTA检查。两名对CTA数据不知情的神经放射科医生根据5分制对ICA狭窄程度进行分级。此外，记录管腔信号强度特征，包括1）信号强度缺失、2）远端血管狭窄和3）远端血管信号强度降低。将MRA结果与CTA结果进行相关性分析，并绘制受试者操作特征（ROC）曲线。
在CTA上，有55条ICA存在≥70%的狭窄，299条ICA不存在≥70%的狭窄。CE-MRA检测≥70%狭窄的敏感性为84%，特异性为96%；2D TOF MRA的敏感性为80%，特异性为95%。CE-MRA的ROC曲线下面积为0.97，2D TOF MRA的ROC曲线下面积为0.95（P = 0.51，无显著性差异）。对于两项MRA研究，每种管腔信号强度特征在检测≥70%狭窄时均具有较高的特异性（>98%），但敏感性较差至中等（35%-66%）。
尽管已证实CE-MRA比非增强二维时间飞跃磁共振血管造影更准确地描绘神经血管解剖结构，但钆剂的使用在区分可手术治疗的ICA狭窄方面并未提供显著优势。这一结论对于有钆剂禁忌证的患者可能具有重要意义。
