T1-Weighted Magnetic Resonance Carotid Plaque Imaging: a Comparison between Conventional and Fast Spin-Echo Techniques.

<bold>Background: </bold>Magnetic resonance imaging is widely used to evaluate the intraplaque components of the cervical carotid artery. The non-gated T1-weighted spin-echo (SE) technique has been reported to have an excellent ability for discriminating stable and unstable plaques. However, the diagnostic performance of various SE-based techniques remains unclear. Hence, we compared plaque signals obtained by 3 kinds of SE-based methods with histological findings.<bold>Methods: </bold>We prospectively examined 40 patients who underwent carotid endarterectomy by using 1.5-T scanners and obtained 2-dimensional (2D) conventional spin-echo (CSE), 2D fast spin-echo (FSE), and 3-dimensional (3D)-FSE images with identical repetition times. We calculated contrast ratios (CRs) of the plaques against adjacent muscles and compared these values with the pathological classification of the specimens.<bold>Results: </bold>The CRs of type VII-VIII (calcific/fibrous), IV-V (lipid-rich/necrotic), and VI (complex/hemorrhagic) plaques were significantly different between all the methods (P <.001) and were discriminated from each other at sensitivities of 83%-100% and specificities of 94%-100%. The CRs of type IV-V plaques significantly differed between the methods (low to high, 2D-FSE, 2D-CSE, and 3D-FSE; P <.05); those of the type VI plaques were significantly lower with the 2D-FSE method than with the other methods (P <.01).<bold>Conclusions: </bold>The SE-based T1-weighted images can readily discriminate plaque characteristics with high sensitivities and specificities, although the signal intensity of unstable plaques was significantly high on the 3D-FSE images and significantly low on the 2D-FSE images. [ABSTRACT FROM AUTHOR]