Magnetic resonance angiography of the carotid arteries: comparison of unenhanced and contrast enhanced techniques

To compare different techniques for carotid imaging including contrast-enhanced, unenhanced and dynamic techniques to find an alternative to contrast-enhanced MRA. 43 patients referred for imaging of the carotids were enrolled in this IRB-approved study. Imaging included dark-blood, time-of-flight, ECG-gated SSFP and dynamic and static contrast-enhanced MRA. Two radiologists evaluated all datasets in terms of image quality (vessel lumen, signal homogeneity, diagnostic confidence, preferred technique) on a four-point Likert-scale and in measuring the vessel area. Of the 43 included patients the first 8 subjects served for protocol optimisation and 4 individuals discontinued the examination. Thus 31 datasets served for evaluation. CE-MRA revealed best results for delineation of vessel lumen, signal homogeneity and diagnostic confidence with values of 3.61, 3.42 and 3.77. It was also rated as the most preferred technique. SSFP-MRA was rated second in all categories with values of 3.1, 2.9 and 3.11. This unenhanced technique was the only one showing non-significantly different results in quantitative analysis. SSFP-MRA, an unenhanced form of MRA, represents an alternative to CE-MRA, particularly in patients where administration of gadolinium for CE-MRA may be contraindicated. In contrast to other techniques, SSFP-MRA serves with not significant different results compared to standard CE-MRA.