HighresolutionMRIofintracranialarterystenosis

Abstract

Purpose : To validate the usefulness of high resolution (HR) MRI in evaluation of intracranial artery stenosis

Materials and Methods : Eighteen intracranial arteries (middle cerebral artery (n=7), basilar artery (n=8), vertebral artery (n=2) and internal carotid artery (n=1)) from 15 patients who had significant intracranial artery stenosis or infarct at the relevant vascular territory on prior MRI were enrolled and undertook HR MRI. The HR MRI was based on pre- and postcontrast proton density-weighted images of transaxial and coronal plane with parameters of TR/TE = 2500/30 msec, FOV = 120 × 105 mm, matrix size = 320 × 220, reconstructed voxel size = 0.23 × 0.23 × 2 mm.

Results : The vascular lesions were either atherosclerosis (n=16) or dissection (n=2). In two patients with proximal MCA dissection, intimal flaps could be demonstrated only on HR MRI. The shape of atheromatous plaques were either eccentric (n=5) or circumferential (n=2). Eccentric plaque had two layers; inner intermediate signal intensity layer (enhanced on postcontrast study) and outer low signal intensity layer. In two patients, the location of eccentric atheromatous plaques of basilar artery correlated well with perforator occlusion leading to pontine infarction.

Conclusion : HR MRI is very useful method in revealing the cause of intracranial stenosis and the different characteristics of atheromatous plaques which may influence on the stroke risk or treatment