Abstract WMP61: Assessment of Carotid Artery Plaques With Chemical Exchange Saturation Transfer Imaging

Abstract

Background: Assessing carotid artery plaques in stenosis is crucial for treatment strategies and safety. Chemical exchange saturation transfer (CEST)-MRI, particularly Amide proton transfer (APT) imaging, shows promise in molecular imaging. This study explores the correlation between APT imaging and histopathological findings of carotid artery plaques in 34 consecutive patients who had carotid endarterectomy. We investigated the utility of CEST-MRI as a preoperative plaque diagnostic tool. Methods: APT imaging evaluated plaques prior to the procedures. APT signal values were derived from concentration maps. Plaques were categorized into Group A (APT signal values ≥ 1.90 E-04) and Group B (APT signal values < 1.90 E-04). Postoperative histopathological assessments were conducted on the excised plaques. Histology slides were categorized following AHA’s classification, distinguishing type VI lesions with intraplaque hemorrhage from non-type VI lesions. Results: Type VI lesions accounted for 64.7% (22 cases), while non-type VI lesions were 35.3% (12 cases). Type VI group showed significantly higher mean APT signal values (2.72 ± 1.96 E-04) compared to non-type VI group (0.70 ± 0.59 E-04) (p < 0.001). Pathologically, Group A had a significantly higher proportion of Type VI lesions (100%) than Group B (45%) (p < 0.01). Symptomatic patients or patients with worsening stenosis rates were significantly higher in Group A (75%) than Group B (36%) (p < 0.01). Conclusion: Elevated APT signals were observed in unstable plaques with intraplaque hemorrhage and in plaques of symptomatic or progressive stenosis patients. CEST-MRI evaluation is valuable for assessing plaque characteristics and activity.