Perioperative ASL-derived CBF change was associated with hemorrhagic and ischemic complications after direct bypass surgery for MMD: marked postoperative CBF elevation was seen with intracranial hemorrhage, whereas insufficient perfusion augmentation was associated with cerebral infarction, and the proposed thresholds are exploratory and require external validation.
Postoperative complications within 90 days after first-time direct bypass for MMD occurred in a minority of the 146 patients, all after the day-5 ASL examination.
Larger ASL-derived CBF change in the recipient territory was associated with postoperative intracranial hemorrhage.
An exploratory CBF-change cutoff for hemorrhage showed very high discrimination, with negligible optimism after bootstrap correction.
Smaller ASL-derived CBF change (insufficient perfusion augmentation) was associated with postoperative cerebral infarction.
An exploratory CBF-change cutoff for cerebral infarction also showed high discrimination.
No significant association was found between ASL-derived CBF change and postoperative seizures.
Standardized perioperative ASL measurement protocol used to assess CBF in the recipient vascular territory.
This study looked at 146 patients with Moyamoya disease, a condition where brain arteries narrow and blood flow is reduced, who had bypass surgery. Using a noninvasive MRI technique (ASL) that estimates blood flow, researchers compared blood flow before surgery and on day 5 after surgery, then followed patients for 90 days to see who had bleeding in the brain, stroke from lack of blood flow, or seizures. They found that patients who had bleeding showed a much larger rise in blood flow in the bypassed area, while patients who had a stroke tended to show little increase. Bleeding occurred in 8 patients (5.5%) and stroke in 14 (9.6%). Seizures (9 patients) were not linked to blood flow changes. The researchers suggested possible cutoff values for the blood flow change that separated these groups well, but these were calculated in the same small group of patients. This research suggests that measuring blood flow change after bypass surgery could help flag patients at risk of either too much or too little blood flow. However, this was a retrospective study from one center with few complication events, and the cutoffs have not been tested in other patient groups, so they are not ready for clinical use.
Lu J, Li C, Su T, Mo Y, Huang G, Tang S, et al.. (2026). Perioperative ASL-derived CBF changes are associated with complications after Moyamoya bypass surgery.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1928443