# Assessment of cerebrovascular reserve using acetazolamide brain perfusion SPECT in Moyamoya disease

## TL;DR

This study shows that acetazolamide SPECT can assess cerebrovascular reserve in Moyamoya disease, helping guide surgical decisions.

## Contribution

The study demonstrates the clinical utility of ACZ-challenged SPECT for evaluating cerebrovascular reserve in Moyamoya disease.

## Key findings

- Post-ACZ SPECT showed 44 regions with improved perfusion, indicating preserved cerebrovascular reserve.
- Type III responses in SPECT correlated with postoperative perfusion defects in a patient who underwent revascularization.
- ACZ-challenged SPECT identified ischemic vulnerability, aiding in the selection of surgical candidates.

## Abstract

Moyamoya disease (MMD) is a rare, progressive steno-occlusive cerebrovascular disorder characterized by impaired cerebral perfusion and an elevated risk of ischemic events. Accurate cerebrovascular reserve (CVR) assessment is crucial for guiding surgical decision-making. This study evaluated the clinical utility of acetazolamide (ACZ)-challenged brain perfusion single-photon emission computed tomography (SPECT) in assessing CVR in patients with MMD.

We retrospectively analyzed 10 patients (6 males, four females; aged 5–65 years) with angiographically confirmed MMD who underwent baseline and post-ACZ 99mTc-ECD SPECT. Regional perfusion across 12 brain regions per patient was visually graded and classified using Rogg’s criteria (Type I–III) to assess CVR.

At baseline, 78/120 regions showed normal perfusion; post-ACZ, this decreased to 72 regions, with an increase in severe hypoperfusion (from 16 to 26 regions). A total of 44 regions demonstrated improved perfusion following ACZ, indicating preserved reserve. According to Rogg’s classification, 63 regions showed Type I, 13 showed Type II, and 39 showed Type III responses. Three patients had infarcts, with two exhibiting crossed cerebellar diaschisis. In a patient who underwent revascularization, new postoperative perfusion defects developed in regions that corresponded to preoperative Type III responses.

ACZ-challenged SPECT effectively characterizes regional CVR in MMD. Identifying Type II and III responses is a valuable predictor for ischemic vulnerability and guides the selection of surgical candidates.