Evaluation of arterial diameter at cranial base in head MRA and neck enhanced MRA

Head MRA and neck enhanced MRA images of blood vessels at cranial base are evaluated and compared. Subjects are 220 patients (M 151, F 69) of ages 15-85 (average 66.5) y, who underwent imaging both by 3D time of flight (TOF) MRA and by neck contrast-enhanced MRA as a screening for the open heart surgery with a 1.5T superconducting machine. Blood vessel images at the cranial base by TOFMRA and enhanced MRA are separately evaluated totally and for stenosis in the bilateral internal carotid and vertebral arteries and basilar artery. All MRA images are found good for evaluation. The degree of stenosis, evaluated by the two kinds of images, agrees with each other in 90.2%, and is overestimated by the enhanced MRA in 8.8% and by the head TOFMRA in 1%. The cause of overestimation is conceivably due to the spatial resolution limit or artifact. (T.I.)