2. CAIN-2B Atherosclerotic plaque imaging using NaF and FDG imaging: Validation and Evaluation of Disease Progression. A sub-study of the Canadian Atherosclerosis Imaging Network (CAIN-2) Histopathology Validation study - patients undergo both NaF and FDG PET/CT preoperatively. All other imaging and study procedures are carried out as per the CAIN-2 study.