Acceleration-selective arterial spin labeling MR angiography tops TOF MR in visualization of distal cerebral arteries, collateral vessels

Acceleration-selective arterial spin-labeling MR angiography provides superior visualization of distal cerebral arteries and collateral vessels in patients with Moyamoya disease than is possible with time-of-flight (TOF) magnetic resonance (MR) angiography, according to a new study.

The research also showed that TOF MR does allow superior visualization of proximal arteries. Moyamoya disease is a rare cerebrovascular steno-occlusive disorder that is most often diagnosed in the people of East Asia.

The study was published online Sept. 15 in Radiology.  Osuamu Togao, who is with the department of clinical Radiology at the Graduate School of Medical Sciences in Fukoka, Japan, led the group.

The TOF technique is the standard approach to intracranial MR angiography. Three-dimensional TOF MR is widely accepted by clinicians, who use the technique to assess lesions in the main arterial trunks and arterial branches. However, TOF MR has drawbacks. For one, the visualization of vessels in TOF MR depends heavily upon blood flows into an imaging slab moving in the inferior-to-superior direction.

“Thus, [TOF MR] is not optimal for visualization of blood flow that is not in the inferior-to-superior direction or of slow flow,” wrote the researchers.

The researchers evaluated and compared the performance of Acceleration-selective arterial spin-labeling MR (AccASL MR) angiography for the visualization of cerebral arteries and collateral vessels in Moyamoya disease patients with the performance of TOF MR angiography using digital subtraction angiography as the reference standard.

Between December 2014 and February 2016, the team analyzed images of 36 cerebral hemispheres from 22 Moyamoya disease patients (9 males and 13 females, with a mean age of 39 + 13.3 years). Half of the 22 patients were adults; half were children.   

The group wrote, “Our present findings showed the clinical potential of ACCASL in the visualization of slow blood flow and flow that is not in the inferior-to-superior direction, both of which are typical clinical limitations of TOF in patients with intracranial steno-occlusive vascular diseases.”

They noted that potential exists for ACCASL angiography and TOF to be employed in a mutually beneficial manner and that further development of AccASL is a goal to be reached before it replaces TOF angiography.