Robust visualization of middle cerebral artery main trunk by enhanced acceleration‐selective arterial spin labeling (eAccASL) for intracranial MRA

Abstract

Purpose A new sequence for intracranial MRA is developed, named enhanced acceleration‐selective arterial spin labeling (eAccASL), to improve main artery visualization at middle cerebral artery (MCA). The aim of this study is to assess the visualization improvement using eAccASL, compared with the previously developed AccASL. Methods eAccASL and AccASL were performed in 8 healthy volunteers and images were compared between the 2 sequences. One patient with Moyamoya disease was evaluated by eAccASL and time of flight. For the volunteer images, vessel visualization was assessed by measuring the contrast‐to‐noise ratio between MCA M1 to M4 and white matter and by counting the peripheral arteries. Venous artifact level was assessed by measuring the contrast‐to‐noise ratio between the confluence of the sinuses and white matter and by evaluating cortical vein visualization. For the patient images, qualitative assessment of peripheral and collateral vessel visualization was conducted. Results In the MCA main trunk, higher arterial signal intensity, with reduced flow void, was observed in eAccASL compared with AccASL. Contrast‐to‐noise ratios of M1 to M3 for eAccASL were significantly higher than those of AccASL. There was no significant difference between AccASL and eAccASL for venous artifact. Conclusion eAccASL could produce better MCA main trunk visualization compared with AccASL, while maintaining good venous signal suppression.

Non-enhanced and Non-gated MR Angiography for Robust Visualization of Peripheral Arteries Using Enhanced Acceleration-selective Arterial Spin Labeling (eAccASL)

“…The MSG strength is defined by the acceleration causing a phase change of p (acceleration-encoding, AENC). 7,8 In this study, we determined AENC value = 0.58 m/s 2 from our experience 7,8 and previous study. 5,6 Here, one of the gradient strength and duration time per gradient direction for eAccASL was 9.43 mT/m and 5.35 ms, respectively; and for cAccASL 2.06 mT/m and 12.35 ms, respectively.…”