The advantage of high-resolution MRI in evaluating basilar plaques: a comparison study with MRA.

OBJECTIVE: Intracranial atherosclerosis (ICAS) is a major cause of ischemic stroke; however it is rather neglected. Vessel wall visualization by high resolution magnetic resonance imaging (HRMRI) might provide more accurate information.
METHODS: A total of 219 consecutive patients with acute ischemic stroke underwent MRI, MRA and proton-density weighted HRMRI. Using HRMRI, the patients were divided into 3 groups with respect to basilar plaques: no plaque (n = 85), minimal plaque (n = 72) and apparent plaque (n = 62). Demographics and characteristics were compared between the groups, and the extents of stenoses calculated from MRA versus HRMRI data were also compared. Factors potentially associated with basilar plaque were validated by multivariate analysis.
RESULTS: Patients with apparent plaque had higher frequencies of diabetes mellitus, lower high-density lipoprotein and higher hemoglobin A1c, erythrocyte sedimentation rate and homocysteine. Of the 62 cases of apparent plaque, severe stenosis (>50%) was observed in 10 (16%) by MRA and in 27 (43%) by HRMRI, which points to overestimation of plaques by HRMRI. In addition, no stenosis was evident on MRA in 13 patients with apparent plaque even though they had up to 72% stenosis on HRMRI. After adjusting for covariates, basilar artery apparent plaque was independently associated with old age, previous stroke, diabetes mellitus, low HDL and high levels of homocysteine.
CONCLUSIONS: Basilar artery stenosis with plaque is more accurately detected using HRMRI than MRA. In addition, the associated risk factors differ somewhat. The use of HRMRI for evaluating ICAS deserves more attention.