Author + information
- Received April 12, 2016
- Revision received June 7, 2016
- Accepted June 15, 2016
- Published online July 3, 2017.
- Joshua T. Chai, DPhila,
- Luca Biasiolli, DPhila,
- Linqing Li, PhDb,
- Mohammad Alkhalil, MDa,
- Francesca Galassi, PhDa,
- Chris Darby, MDc,
- Alison W. Halliday, MSc,
- Linda Hands, MSc,
- Timothy Magee, MDc,
- Jeremy Perkins, MDc,
- Ed Sideso, MBBSc,
- Ashok Handa, MBBSc,
- Peter Jezzard, PhDd,
- Matthew D. Robson, PhDa and
- Robin P. Choudhury, DMa,∗ ()
- aDivision of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- bNational Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
- cNuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
- dFMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- ↵∗Address for correspondence:
Prof. Robin P. Choudhury, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Level 6, West Wing, Oxford OX3 9DU, United Kingdom.
Objectives The aim of this study was to: 1) provide tissue validation of quantitative T2 mapping to measure plaque lipid content; and 2) investigate whether this technique could discern differences in plaque characteristics between symptom-related and non–symptom-related carotid plaques.
Background Noninvasive plaque lipid quantification is appealing both for stratification in treatment selection and as a possible predictor of future plaque rupture. However, current cardiovascular magnetic resonance (CMR) 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 3-T carotid CMR 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 T2 maps was significantly higher in symptomatic compared with asymptomatic plaques (31.5 ± 3.7% vs. 15.8 ± 3.1%; p = 0.005) despite similar degrees of carotid stenosis and only modest difference in plaque volume (128.0 ± 6.0 mm3 symptomatic vs. 105.6 ± 9.4 mm3 asymptomatic; p = 0.04). Receiver-operating characteristic analysis showed that T2 mapping has a good ability to discriminate between symptomatic and asymptomatic plaques with 67% sensitivity and 91% specificity (area under the curve: 0.79; p = 0.012).
Conclusions CMR T2 mapping distinguishes different plaque components and accurately quantifies plaque lipid content noninvasively. Compared with asymptomatic plaques, greater lipid content was found in symptomatic plaques despite similar degree of luminal stenosis and only modest difference in plaque volumes. 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).
Dr. Chai was supported by the Medical Research Council and Stroke Association UK (grant MR/K00266X/1). Dr. Biasiolli was supported by the Engineering and Physical Sciences Research Council. Dr. Li was supported by the British Heart Foundation. Prof. Jezzard was supported by the Dunhill Medical Trust. Prof. Choudhury was a Wellcome Trust Senior Clinical Fellow. Dr. Li and Prof. Jezzard patented the DANTE black-blood preparation approach and licensed it to Siemens. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Chai and Biasiolli are joint first authors. Profs. Robson and Choudhury are joint senior authors.
- Received April 12, 2016.
- Revision received June 7, 2016.
- Accepted June 15, 2016.
- 2017 American College of Cardiology Foundation