Characterisation of carotid atheroma in symptomatic and asymptomatic patients using high resolution MRI
- J M U-King-Im1,
- T Y Tang1,3,
- A Patterson1,
- M J Graves1,
- S Howarth1,
- Z-Y Li1,
- R Trivedi1,
- D Bowden1,
- P J Kirkpatrick2,
- M E Gaunt3,
- E A Warburton2,
- N M Antoun1,
- J H Gillard1
- 1 University Department of Radiology, Addenbrooke’s Hospital, Cambridge, UK
- 2 Academic Department of Neurosurgery, Addenbrooke’s Hospital, Cambridge, UK
- 3 Department of Vascular Surgery, Addenbrooke’s Hospital, Cambridge, UK
- Dr J H Gillard, University Department of Radiology, Addenbrooke’s Hospital and the University of Cambridge, Cambridge CB2 2QQ, UK;
- Received 20 June 2007
- Revised 5 December 2007
- Accepted 6 December 2007
- Published Online First 10 January 2008
Background and purpose: To prospectively evaluate differences in carotid plaque characteristics in symptomatic and asymptomatic patients using high resolution MRI.
Methods: 20 symptomatic and 20 asymptomatic patients, with at least 50% carotid stenosis as determined by Doppler ultrasound, underwent preoperative in vivo multispectral MRI of the carotid arteries. Studies were analysed both qualitatively and quantitatively in a randomised manner by two experienced readers in consensus, blinded to clinical status, and plaques were classified according to the modified American Heart Association (AHA) criteria.
Results: After exclusion of poor quality images, 109 MRI sections in 18 symptomatic and 19 asymptomatic patients were available for analysis. There were no significant differences in mean luminal stenosis severity (72.9% vs 67.6%; p = 0.09) or plaque burden (median plaque areas 50 mm2 vs 50 mm2; p = 0.858) between the symptomatic and asymptomatic groups. However, symptomatic lesions had a higher incidence of ruptured fibrous caps (36.5% vs 8.7%; p = 0.004), haemorrhage or thrombus (46.5% vs 14.0%; p<0.001), large necrotic lipid cores (63.8% vs 28.0%; p = 0.002) and complicated type VI AHA lesions (61.5% vs 28.1%; p = 0.001) compared with asymptomatic lesions. The MRI findings of plaque haemorrhage or thrombus had an odds ratio of 5.25 (95% CI 2.08 to 13.24) while thin or ruptured fibrous cap (as opposed to a thick fibrous cap) had an odds ratio of 7.94 (95% CI 2.93 to 21.51) for prediction of symptomatic clinical status.
Conclusions: There are significant differences in plaque characteristics between symptomatic and asymptomatic carotid atheroma and these can be detected in vivo by high resolution MRI.
Funding: This study was partly funded by a grant from the Stroke Association UK.
Competing interests: None.
Ethics approval: The study had approval from the local ethics committee.