PET-MRI Imaging in Patients With Symptomatic Carotid Artery Stenosis

The ability to identify the culprit carotid plaque represents a key goal in carotid artery imaging. Although an array of non-invasive imaging techniques can detect a wide spectrum of complementary high-risk characteristics, no single modality can reliably identify vulnerable plaques associated with future stroke development. Substantial histological data suggests that specific plaque components identify patients at high-risk for future ipsilateral stroke and cardiovascular events. This implies that investigators need to look beyond the traditional paradigm where the basis for carotid endarterectomy were formulated by an invasive imaging modality that provided no information on the arterial wall composition. Alternative imaging strategies are therefore required targeting not only in vivo carotid morphology but also plaque biology and disease activity. This is fundamental to optimal risk-stratification and appropriate selection of patients for high-risk vascular intervention. One new approach is to use non-invasive molecular imaging targeted at plaque biology using hybrid systems such as positron emission tomography-magnetic resonance imaging.

Inclusion criteria

• Patients with carotid artery stenosis (>50% for men and >70% for women, by NASCET criteria) above 40 years of age.

Exclusion criteria

• Patients with new stroke and a modified Rankin score >3
• Chronic kidney disease with an estimated Glomerular Filtration Rate (eGFR) of <30 ml/min/1.73 m2
• Atrial fibrillation
• Pregnant women
• Prior ipsilateral carotid intervention
• Prior neck radiotherapy
• Inability to tolerate the supine position
• Participation in the study would result in delay to surgery
• Psychiatric illness/social situations that would limit compliance with study requirements
• History of allergic reaction attributed to 18F-fluoride
• History of allergic reaction to gadolinium contrast media
• Metal implants and devices including pacemakers and defibrillators