Quantification of lipid-rich core in carotid atherosclerosis using MRI T2 mapping - relation to clinical presentation

Journal article

Objectives

This study aimed to: (1) provide tissue validation of quantitative T2 maps to measure plaque lipid content; and (2) to investigate whether this technique could discern differences in plaque characteristics between symptom-related and non symptom-related carotid plaques.

Background

Non-invasive plaque lipid quantification is appealing both for stratification in treatment selection and as a possible predictor of future plaque rupture. However, current magnetic resonance imaging (MRI) methods are insensitive, require a coalesced mass of lipid ‘core’ and rely on multicontrast acquisition with contrast media and extensive post-processing.

Methods

Patients scheduled for carotid endarterectomy were recruited for 3T carotid MRI before surgery. Lipid Area was derived from segmented T2 maps and compared directly to plaque lipid defined by histology.

Results

Lipid Area (%) on T2 mapping and histology showed excellent correlation, both by individual slices (R = 0.85, P < 0.001) and plaque average (R = 0.83, P < 0.001). Lipid Area (%) on T¬2 maps was significantly higher in symptomatic compared to asymptomatic plaques (31.5 ± 3.7% vs. 15.8 ± 3.1%, P = 0.005) despite similar degrees of carotid stenosis. Receiver operating characteristic curve analysis showed that T2 mapping has a fair to good ability to discriminate between symptomatic and asymptomatic plaques.

Conclusions

MRI T2 mapping accurately quantifies plaque lipid content non-invasively. Greater plaque lipid content was found in symptomatic plaques. This new technique may find a role in determining optimum treatment e.g. providing an indication for intensive lipid lowering or by informing decisions of stents vs. surgery.

Authors: Halliday, A; Chai, J; Biasiolli, L; Li, L; Alkhali, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: JACC: Cardiovascular Imaging
• Volume: 10
• Issue: 7
• Pages: 747–756
• Publication date: 2016-10-01
• Acceptance date: 2016-06-16
• DOI: 10.1016/j.jcmg.2016.06.013*