The investigators use MRI and/or CT to evaluate the extent, as well as, the structure, composition, and functional aspects of atherosclerotic plaques in human carotid and femoral arteries in patients scheduled to undergo an endarterectomy of the aforementioned vascular beds as part of their routine clinical care.

The investigators hypothesize that in vivo MRI and/or CT examinations of patients, when suitably acquired and analyzed with the vascuCAP™ analysis software, can provide a sufficiently accurate profile of plaque characteristics to provide an objective basis for patient management. Study subjects include patients undergoing endarterectomies to mitigate their clinical risk or symptoms for conditions including stroke, claudication, and critical limb ischemia. The endarterectomy specimens removed at surgery will allow a direct comparison between the MRI information obtained prior to the surgery and the histopathological analyses of the arterial specimens. The vascuCAP™ measurements of structural and functional features of the arterial wall will be performed in patients undergoing endarterectomy. Measured results will be compared in a blinded fashion with histology to assess performance of plaque profiling and build a pilot prediction model for risk scoring.

Inclusion Criteria:

Individuals must meet one of the following inclusion criteria in order to be eligible to participate in the study:

• Case subjects will be patients with documented carotid atherosclerosis, scheduled for magnetic resonance or CT angiography and subsequent elective endarterectomy with 30 days of enrollment in the study
• Case subjects will be patients with peripheral arterial disease (PAD) with clinical symptoms, scheduled for magnetic resonance or CT angiography and indicated endarterectomy of diseased areas of femoral arteries within 30 days of enrollment in the study

Exclusion Criteria:

• Subjects with claustrophobia or inability to tolerate prior MRI studies.
• Subjects with metal implants that are not MRI compatible (LSU detailed checklist to be attached) including: Subjects with any type of bio-implant activated by mechanical, electronic, or magnetic means (e.g. cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.). Subjects with any type of ferromagnetic bio-implant that could potentially be displaced or damaged, such as aneurysm clips, metallic skull plates, etc.
• Subjects with a history of kidney disease or dialysis that are unable to receive intravenous gadolinium contrast material.
• Female subjects. A urine pregnancy test will be required of all female subjects of childbearing potential prior to inclusion in this study. Pregnant or nursing females will be excluded from the study.
• Subjects who cannot adhere to the experimental protocol.
• Subjects allergic to contrast material.

Individuals must meet one of the following inclusion criteria in order to be eligible to participate in the study:

• Case subjects will be patients with documented carotid atherosclerosis, scheduled for magnetic resonance or CT angiography and subsequent elective endarterectomy with 30 days of enrollment in the study
• Case subjects will be patients with peripheral arterial disease (PAD) with clinical symptoms, scheduled for magnetic resonance or CT angiography and indicated endarterectomy of diseased areas of femoral arteries within 30 days of enrollment in the study

from time of enrollment through endarterectomy procedure, an average of 1 month

The study protocol was written to ensure that the study have no effect on either diagnosis or treatment of enrollees.