High resolution imaging of the intracranial vessel wall at 3 and 7T using 3D fast spin echo MRI.

Abstract

High resolution MRI of the intracranial vessel wall provides important insights in the assessment of intracranial vascular disease. This study aims to refine high resolution 3D MRI techniques for intracranial vessel wall imaging at both 3 and 7T using customized flip angle train design, and to explore their comparative abilities. 11 patients with intracranial artery disease (four atherosclerotic plaques, six aneurysms and one reversible cerebral vasoconstriction syndrome) were imaged at 3 and 7T with a 3D T 1-weighted fast-spin-echo sequence (SPACE) both pre and post Gd contrast injection. Wall to lumen contrast ratio (CRwall-lumen), contrast enhancement ratio (ER) and the sharpness of the vessel wall were quantified. Two experienced radiologists evaluated the image quality on a 0-5 scale. Both 3 and 7T achieved good image quality with high resolution (nominal 0.5mm isotropic) and whole brain coverage. The CRwall-lumen and the ER measurements were comparable (p>0.05). The 7T images were significantly sharper (sharpness: 2.69±0.50 vs. 1.88±0.53mm(-1), p<0.001) with higher image quality (reader 1 score: 3.5±1.1 vs. 2.4±1.1, p=0.002) compared to 3T. 3D T 1-weighted SPACE can be used for intracranial vessel wall evaluation at both 3 and 7T. 7T provides significantly better image quality and improves the confidence of diagnosis.