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Abstract Contrast enhanced magnetic resonance angiography (CE MRA) is a non-invasive alternative to conventional digital subtraction angiography (DSA). CE MRA is increasingly used as a complement to Duplex in the preoperative assessment of carotid artery stenosis. The purpose of this study was to determine if CE MRA could replace preoperative DSA. CE MRA with a scan time of 10 or 28 s was performed in 24 consecutive patients who were scheduled for preoperative DSA because of Duplex-verified severe carotid artery stenosis. Two neuroradiologists measured the degree of stenosis with three different methods, and the image quality was evaluated. DSA was used as the gold standard. For detection of severe stenosis (N. American symptomatic carotid endarterectomy trial (NASCET) > or =70%; European symptomatic carotid endarterectomy trial (ECST) > or =80%; common carotid artery method (CCAM) > or =80%), the sensitivity of CE MRA maximum intensity projection (MIP) compared with DSA was 82%-100 %, the specificity was 74%-93% and the accuracy was 77% 90%. The inter-observer agreement was higher, the image quality was better and the intracranial main arteries were better visualized with the 28 s than with the 10 s scan time. The enhancement of the jugular veins seen in 17% of the 10 s scans and in 58% of the patients with the 28 s scans did not interfere with the evaluation of the carotid arteries. CE MRA, preferably with a scan time of 28 s, can replace DSA in the preoperative assessment of most patients with carotid artery stenosis.
Keywords Carotid arteries * Stenosis * Magnetic resonance contrast enhancement * Magnetic resonance angiography * Digital subtraction angiography
Introduction
Catheter-based angiographie techniques have been the gold standard for diagnosis of carotid artery stenosis and are the sole basis for treatment decisions in the N. American symptomatic carotid endarterectomy trial (NASCET) and European symptomatic carotid endarterectomy trial (ECST). Their most important drawback is the 1% incidence of significant stroke caused by the selective arterial catheterization. Therefore, a non-invasive alternative such as magnetic resonance angiography (MRA) is preferable.
Several MRA techniques such as two-dimensional time-of-flight (2D TOF) and single- or multiple-slab three-dimensional time-of-flight (3D TOF) have been implemented for the assessment of extra-cranial carotid-artery disease. These methods require an imaging time of 5 to 10 min...