The objective of this study is to validate 2 multi-contrast sequences, namely the Multi-contrast ATherosclerosis Characterization (MATCH) and Bright-blood and black-blOOd phase SensiTive (BOOST) inversion recovery sequence for the quantification of atherosclerotic plaque components with conventional multi-sequence MRI and histology.

Rationale: Rupture of a vulnerable atherosclerotic plaque is the most important cause of stroke and myocardial infarction. Magnetic Resonance Imaging (MRI) with its high soft tissue contrast is well suited for atherosclerotic plaque imaging to identify high-risk plaques. High soft tissue contrast enables the visualisation of different plaque components based on which the plaque can be classified as stable or vulnerable. To identify the various plaque components, in a conventional MRI examination multiple MRI sequences are acquired, which can take approximately 30-40 minutes. This can be uncomfortable for the patient and it is impractical in daily clinical practice. As an alternative, multi-contrast sequences have recently been developed which acquire multiple contrast weightings simultaneously, significantly reducing the scan time (< 6 minutes). Apart from a reduction in scan time, because these contrast weightings are acquired simultaneously, they are inherently co-registered which is not the case with conventional sequences.

Objective: The objective of this study is to validate 2 multi-contrast sequences, namely the Multi-contrast ATherosclerosis Characterization (MATCH) and Bright-blood and black-blOOd phase SensiTive (BOOST) inversion recovery sequence for the quantification of atherosclerotic plaque components with conventional multi-sequence MRI and histology.

Study design: cross-sectional validation study Study population: 40 patients with a carotid artery plaque ≥2 mm based on ultrasound or Computed Tomography Angiography.

Intervention (if applicable): not applicable Main study parameters/endpoints: the presence and volumetric measures of plaque components (fibrous tissue, lipid-rich necrotic core, intraplaque hemorrhage and calcifications) and volumetric measures of the vessel wall and lumen as assessed with multi-contrast MRI will be compared to those as assessed by conventional multisequence MRI and, if available, histology of the surgically removed specimen in patients that are scheduled for carotid endarterectomy.

Inclusion Criteria:

In order to be eligible to participate in this study, a subject must meet the following criteria:

• Patients with a carotid plaque ≥ 2 mm thick based on ultrasound or CTA
• Age 18 years or older (no maximum age)
• Informed consent by signing informed consent form regarding this study

Exclusion Criteria:

A potential subject who meets any of the following criteria will be excluded from participation in this study:

• Patients with carotid plaque ≤ 2 mm in size based on ultrasound or CTA
• Standard contra-indications for MRI (electronic implants like pacemakers or other electronic implants, metallic eye fragments, vascular clips, claustrophobia, etc.)
• Severe co-morbidity, dementia or pregnancy

40 patients (18 years or older) with a carotid plaque ≥ 2 mm based on ultrasound or CTA, will be included in this study. These patients will undergo a 3T MRI scan. Inclusion will be done by an investigator. All the research will take place at Maastricht University Medical Centre (MUMC). Vascular surgeons, neurophysiologists and neurologists at MUMC are willing to participate in this study. Some of the included patients will be scheduled for CEA as part of standard clinical care. The MRI scan of these patients will take place at least one day before CEA is performed. At MUMC, approximately 10 patients per month fit the criteria (≥ 2 mm carotid plaque size).