High resolution MRI of intracranial artery stenosis

Abstract

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

Materials and Methods : Thirty-six intracranial arteries (9 middle cerebral arteries, 21 basilar arteries and 6 vertebral arteries) from 31 patients who had significant intracranial stenosis on prior MRA or infarction 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=3). Four different signal and morphological characteristics (eccentric plaque with or without innermost high signal intensity layer, and concentric plaque with or without innermost high signal intensity layer) of atherosclerotic lesions were found in transaxial HR MRIs. Perforator jailing was more related to the signal characteristics (innermost high signal intensity layer) than the severity of stenosis. Dissection could be clearly differentiated from atherosclerosis by demonstrating intimal flap.

Conclusion : HR MRI may be a useful method in defining the different characteristics of atheromatous plaques which may influence on the stroke risk or treatment strategy.