Abstract 11236: Acute 3T Magnetic Resonance Imaging Reveals Features of Carotid Atherosclerotic Plaque Associated with Ipsilateral Cerebral Infarction in Minor Stroke and Transient Ischemic Attack
Background: Magnetic Resonance Imaging (MRI) of the carotid artery can detect features of atherosclerotic plaque that may be associated with an increased stroke risk. This study tested the ability of MRI at 3 Tesla to identify features of acutely symptomatic carotid plaques and their association with downstream brain injury.
Methods: 41 patients presenting acutely with TIA or minor stroke and 40 asymptomatic controls underwent dark-blood T1, T2 and proton density-weighted turbo spin echo MRI of the carotid arteries, followed by diffusion-weighted (DWI) and FLAIR imaging of the brain on 2 separate occasions. Plaques were graded (MRI modified American Heart Association system) and related to the extent of MRI-determined brain injury.
Results: AHA type VI (ruptured) plaque was seen in 22 / 41 (54 %) in the symptomatic group vs. 8 / 40 (20 %) in the asymptomatic group (P < 0.05), and was due to intra-plaque haemorrhage (34% vs. 18%, P = 0.08; figure A), luminal thrombus (7% vs. 0%, P = 0.24; figure B), or surface rupture (24% vs. 5%, P = 0.03; figure C). Of particular note, 17 / 30 (57 %) cases of AHA VI (ruptured) plaque were seen in vessels with < 70% stenosis. At follow up scanning a minimum of six weeks later, only two cases of symptomatic AHA VI plaque showed evidence of full healing. The presence of fibrous cap rupture independently predicted brain injury burden at presentation, and a higher number of DWI lesions overall (P < 0.05) In addition, patients with surface rupture also had higher total cerebral FLAIR signal at follow-up (P < 0.05; figure, lower panels).
Conclusion: Early carotid wall MRI in acute minor stroke and TIA, showed a higher proportion of ‘complex' plaques, compared to asymptomatic controls, of which a, majority were in arteries of < 70% stenosis. Plaque rupture was associated with increases in both diffusion weighted (DWI) and FLAIR lesions in the brain, raising the possibility of risk stratification with this non-invasive technique
- © 2011 by American Heart Association, Inc.