Abstract
Purpose: The characteristics of carotid artery plaques were evaluated by both MRI and enhanced CT and the results were compared between the two modalities.
Methods: Between October 2007 and September 2009, 35 vessels in 35 patients with carotid artery stenosis of more than 70% were treated by carotid artery stenting and included in the analysis. Nineteen vessels demonstrating high signal intensity on BB-MRI were categorized as an unstable plaque group (U group), and 16 demonstrating iso-low signal intensity on BB-MRI were categorized as a stable plaque group (S group). CE-CT evaluation of the carotid plaques was conducted by obtaining average CT numbers in Hounsfield units (HU) of three random regions-of-interest (ROI) in each plaque. In addition, plaque/muscle ratios (P/M) were measured by BB-MRI T1W. The CT numbers of the U and S groups and the correlation between HU and P/M ratios were evaluated.
Results: The average CT number of the U group was 35.4 HU and that of the S group was 80.2 HU, with a significant difference between the two groups by the Mann-Whitney test (p < 0.01). Furthermore, there was a significant correlation between the HU and P/M ratios in the plaques (r = -5.89, p < .0001).
Conclusion: In assessing carotid plaques, a good correlation between MRI and CT findings was obtained in this study. Since diagnosis by CT is more speedy and simpler than with MRI, this diagnostic modality may thus be preferable for evaluation of carotid lesions.
