Turnipseed W D, Kennell T W, Turski P A, Acher C W, Hoch J R
Department of Surgery, University of Wisconsin, Madison.
J Vasc Surg. 1993 May;17(5):832-9; discussion 839-40. doi: 10.1067/mva.1993.45110.
Advances in cerebral vascular imaging suggest that patients with critical levels of carotid artery stenosis (> 70%) who have symptoms can be identified accurately and necessary information about the intracranial and extracranial circulation obtained before surgery without conventional angiography. We have used carotid duplex imaging in combination with magnetic resonance angiography (MRA) to evaluate 20 patients with symptomatic ipsilateral high-grade carotid stenosis.
All patients underwent CT and magnetic resonance imaging brain scans, as well as MRA and conventional arteriography of the cerebral circulation. Magnetic resonance angiograms were obtained with two-dimensional phase contrast and time-of-flight techniques. Phase contrast was used for intracranial vascular imaging and for determining qualitative flow velocities and the direction of blood flow in the circle of Willis. Two-dimensional time of flight was used to assess the carotid bifurcations.
Twenty patients with symptoms (six with strokes, 11 with transient ischemic attacks, and three with amaurosis fugax) had duplex evidence of high-grade carotid stenoses. Computed tomographic and magnetic resonance brain scans were positive for cerebral infarction in six patients with clinical strokes. Comparison of MRA with conventional angiography was 91% accurate for high-grade stenoses and occlusions (sensitivity 100% and specificity 90% for stenosis; sensitivity/specificity was 100% for complete occlusion). Comparison of duplex imaging with conventional angiography demonstrated 86% accuracy for detection of severe stenosis or occlusion (sensitivity 94% and specificity 89% for stenosis; sensitivity and specificity were 100% for complete occlusion).
This study suggests that combined use of MRA and duplex imaging is accurate for detection and evaluation of high-grade carotid stenoses in patients with symptoms.
脑血管成像技术的进展表明，对于有症状的颈动脉严重狭窄（>70%）患者，无需进行传统血管造影，即可准确识别，并在手术前获得有关颅内和颅外循环的必要信息。我们联合使用颈动脉双功超声成像和磁共振血管造影（MRA）对20例有症状的同侧重度颈动脉狭窄患者进行了评估。
所有患者均接受了脑部CT和磁共振成像扫描，以及MRA和脑部循环的传统动脉造影。采用二维相位对比和时间飞跃技术获取磁共振血管造影图像。相位对比用于颅内血管成像以及确定Willis环内血流速度的定性和血流方向。二维时间飞跃用于评估颈动脉分叉处。
20例有症状的患者（6例中风，11例短暂性脑缺血发作，3例一过性黑矇）有双功超声显示重度颈动脉狭窄的证据。6例临床中风患者的计算机断层扫描和磁共振脑部扫描显示脑梗死呈阳性。MRA与传统血管造影对重度狭窄和闭塞的对比准确率为91%（狭窄的敏感性为100%，特异性为90%；完全闭塞的敏感性/特异性为100%）。双功超声成像与传统血管造影的对比显示，检测严重狭窄或闭塞的准确率为86%（狭窄的敏感性为94%，特异性为89%；完全闭塞的敏感性和特异性均为100%）。
本研究表明，联合使用MRA和双功超声成像在检测和评估有症状患者的重度颈动脉狭窄方面是准确的。
