FIG 2. 3D time-of-flight MR angiograms and blood flow velocity data plots.

A, 3D time-of-flight MR angiogram (33/4; flip angle, 20 degrees) of a 49-year-old male patient with PCI and dizziness shows narrowing of the right vertebral and basilar arteries. Change of blood flow velocity between systolic and diastolic phases was greater in the patient than in the normal control volunteer (see B).

B, 3D time-of-flight MR angiogram (33/4; flip angle, 20 degrees) of a 54-year-old female control participant with no clinical signs or symptoms shows mild meandering of the basilar artery.