A study of disrupted carotid plaque using high-resolution MRI

Objective To evaluate distribution features of disrupted carotid plaque. Methods Forty-three subjects with duplex ultrasound evidence of 50% to 99% stenosis were retrospectively analyzed. Plaques were categorized as disrupted if there was MRI evidence of fibrous cap rupture. Quantity measured areas of the lumen (LA), wall (WA), and plaque components. The morphological parameters used were total vessel area, vessel burden index, eccentricity index. Mann-Whitney test and Chi-square test appropriate used SPSS (v. 12.0 ). Results There were 17 disrupted and 26 undisrupted lesions identified for comparison. Disrupted plaques showed a predominance of longer longitudinal length of large lip nucleus along the vessel wall (6 mm vs. 0 mm, U = 126, P <0.05 ), a large vessel burden (0.67 vs. 0.59, U =105, P <0.05), and high prevalence of thrombus (82.4% vs. 42.3 %, U = 132,P <0.05). In addition, disrupted plaques showed a different pattern of plaque distribution, having a more eccentric position of the lumen (3.68 vs. 2.79, U = 126, P < 0.05 ), a smaller lumen area (23.97 mm2 vs. 30. 18 mm2, U = 138, P<0.05) and a longer segment of stenosis when compared with the intact plaques. Conclusions Disrupted plaques have significantly different characteristics in terms of both axial and longitudinal distribution. A combination of multi-plane and multi-contrast high resolution MRI may provide valuable information about overall lesion morphology and its association to vulnerability. Key words: Carotid stenosis;  Magnetic resonance imaging;  Imaging process, computer-assisted