Atherosclerotic plaques: Classification and characterization with T2-weighted high-spatial-resolution MR imaging - An in vitro study

PURPOSE: To evaluate if T2-weighted high-spatial-resolution magnetic resona nce (MR) imaging (117 mum per pixel) can help accurate classification of at herosclerotic plaques. MATERIALS AND METHODS: Thirty human arteries and 11 carotid endarterectomy specimens from 31 patients underwent T2-weighted MR imaging (2-T magnet; re petition time, 2,000 msec; echo time, 50 msec) at room temperature. After i maging, Bouin fixative was used to fix 26 arteries, and the other 15 arteri es were fixed by means of freezing. Specimens were stained with hematoxylin -eosin and safranin or Sudan lipid stain. MR images and histologic slices w ere classified independently by two radiologists and a pathologist, respect ively, on the basis of the American Heart Association classification. RESULTS: Results with MR imaging were the following: type I-II plaques, sen sitivity of 67% and specificity of 100%; type IV-Va plaques, sensitivity of 74% and specificity of 85%; type Vb plaques, sensitivity of 90% and specif icity of 100%; type Vc plaques, sensitivity of 80% and specificity of 90%. No type III plaque was diagnosed in the study. The overall K value was 0.68 . CONCLUSION: High-spatial-resolution MR imaging with T2 weighting alone can help accurate classification of fibrocalcic plaques (type Vb), but it is su bject to limitations for the classification and analysis of other types of atherosclerotic plaques.