5.0T MRA techniques for evaluating Moyamoya disease: 4D-ASL-MRA vs. 3D-TOF-MRA

Area of Science:

• Radiology
• Neuroimaging
• Vascular Imaging

Background:

• Three-dimensional time-of-flight MR-angiography (3D-TOF-MRA) is established for visualizing small vessels.
• Arterial spin labeling (ASL)-based four-dimensional MR-angiography (4D-ASL-MRA) offers potential for enhanced vascular imaging.
• Direct comparison of 4D-ASL-MRA and 3D-TOF-MRA at 5.0T for Moyamoya disease (MMD) evaluation is lacking.

Purpose of the Study:

• To compare the diagnostic performance of 4D-ASL-MRA and 3D-TOF-MRA at 5.0T in patients with Moyamoya disease (MMD).
• To assess the visualization capabilities and accuracy of MMD staging between the two MRA techniques.

Main Methods:

• Retrospective analysis of 20 MMD patients who underwent both 4D-ASL-MRA (with six labeling times) and 3D-TOF-MRA at 5.0T.
• Evaluation included Suzuki grades, contrast-to-noise ratio (CNR), middle cerebral artery (MCA) branch visualization, and image scoring of key vascular structures.

Main Results:

• 4D-ASL-MRA (900-1800 ms labeling times) showed superior visualization scores for terminal internal carotid arteries (ICA), stenosis, and leptomeningeal anastomosis (LMA) compared to 3D-TOF-MRA.
• 4D-ASL-MRA demonstrated significantly more visible distal MCA branches and higher CNR in the M4 segment.
• Inter-modality agreement for Suzuki grading was excellent between 4D-ASL-MRA and digital subtraction angiography (DSA) (κ=0.88), surpassing 3D-TOF-MRA (κ=0.57).

Conclusions:

• At 5.0T, 4D-ASL-MRA provides superior visualization of terminal ICA, distal MCA, and collateral vessels in MMD patients.
• 4D-ASL-MRA enables more accurate staging of MMD compared to 3D-TOF-MRA at 5.0T.