Surface appearance of the vertebrobasilar artery revealed on basiparallel anatomic scanning (BPAS)-MR imaging: its role for brain MR examination

Basiparallel anatomic scanning (BPAS)-MR imaging is a simple MR imaging technique that we designed for visualization of the surface appearance of the vertebrobasilar artery within the cistern. It can clearly show the outer contour of occluded arteries or thrombosed aneurysms. By comparing BPAS-MR imaging with 3D time-of-flight (TOF) MR angiography (MRA), we can precisely evaluate the vertebrobasilar artery condition. The purpose of this study is to determine the value of BPAS-MR imaging for brain MR examination.

We obtained BPAS-MR imaging, in addition to 3D TOF MRA, for 385 consecutive patients who underwent brain MR imaging and MRA in our hospital between April 1 and August 31, 2003. Their complaints varied from mild head symptoms to severe neurologic illness. Comparing BPAS-MR imaging with MRA, we revealed the character of BPAS-MR imaging and determined the role and value of displaying vascular outer contour.

Although the cases did not represent a restricted group of vertebrobasilar diseases, BPAS-MR imaging contributed to accurate evaluation of the vertebrobasilar artery in 90 of our 385 patients (23.4%). Of particular note, 16.1% of our patients could not be evaluated accurately by MRA only. BPAS-MR imaging was useful to confirm hypoplastic or occluded vertebral arteries and to reveal the whole appearance of large or partially thrombosed aneurysms of the vertebrobasilar system.

The combination of the BPAS-MR imaging and the 3D TOF MRA was necessary for accurate diagnosis in 16.1% of our ordinary patients. We should evaluate not only MRA but also the vascular outer contour revealed on BPAS-MR imaging, though its application is limited to the vertebrobasilar system and the screening use.