Noninvasive determination of plaque vulnerability has been a holy grail of medical imaging. Despite advances in
tomographic technologies , there is currently no effective way to identify vulnerable atherosclerotic plaques with high
sensitivity and specificity. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used, but
neither provides sufficient information of plaque properties. Thus, we are motivated to combine CT and MRI imaging to
determine if the composite information can better reflect the histological determination of plaque vulnerability. Two
human endarterectomy specimens (1 symptomatic carotid and 1 stable femoral) were imaged using Scanco Medical Viva
CT40 and Bruker Pharmascan 16cm 7T Horizontal MRI / MRS systems. μCT scans were done at 55 kVp and tube
current of 70 mA. Samples underwent RARE-VTR and MSME pulse sequences to measure T1, T2 values, and proton
density. The specimens were processed for histology and scored for vulnerability using the American Heart Association
criteria. Single modality-based analyses were performed through segmentation of key imaging biomarkers (i.e.
calcification and lumen), image registration, measurement of fibrous capsule, and multi-component T1 and T2 decay
modeling. Feature differences were analyzed between the unstable and stable controls, symptomatic carotid and femoral
plaque, respectively. By building on the techniques used in this study, synergistic CT+MRI analysis may provide a
promising solution for plaque characterization in vivo.