Robert Goetti

In children with Moyamoya disease, cerebral perfusion studies are essential for preoperative planning and postoperative follow-up after revascularization procedures. As these children often undergo repeat examinations, the potential cumulative radiation burden of nuclear medicine studies, DSA, and CT is considerable and should be minimized as far as reasonably achievable.

Nuclear medicine perfusion studies have been shown to be of great value in the assessment of patients with Moyamoya disease. We therefore sought to evaluate if arterial spin-labeling (ASL) MRI could provide comparable information without using ionizing radiation.

In the present study, we were able to demonstrate that assessment of cerebral perfusion in children with Moyamoya disease using ASL-MRI is possible with a strong and significant correlation with the current reference standard of H₂[¹⁵O]-PET after cerebellar normalization.

In clinical practice this means that cerebral perfusion imaging of children with Moyamoya disease can be performed without the use of ionizing radiation or injection of an exogenous contrast agent. In children who are old enough to undergo MRI without general anesthesia or sedation, a comprehensive study with multiplanar T1, T2, FLAIR imaging, time-of-flight MR angiography, diffusion-weighted imaging, and ASL requires no cannulation. This makes regular follow-up imaging a much more agreeable experience for these young patients.

As arterial spin-labeling MRI is repeatable and allows for quantitative assessment, it is also a great candidate for the evaluation of cerebral perfusion reserve with azetazolamide challenge. If this capability of ASL

can be demonstrated in further studies, MRI may safely replace PET and SPECT for preoperative functional vascular assessment in children with Moyamoya disease, substantially lowering their radiation burden and allowing a one-stop shop assessment of parenchymal and vascular morphology as well as functional cerebral perfusion.

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