Predictive value of CT perfusion-derived parameters in Moyamoya disease

Objective: To explore the applicability of CT perfusion-derived parameters and collateral index in prediction of functional and clinical outcomes in patients with Moyamoya disease (MMD) who have not been treated surgically.Methods: All hemispheres were categorized into four groups: those with ischemic (IS) lesions, hemorrhagic (HE) lesions, subarachnoid hemorrhage (SAH) and normal hemisphere (NH). The clinical review included primary outcomes (whether a patient survived the cerebrovascular event) and secondary outcomes (the modified Rankin scale [mRS] and Katz-activity of daily living [ADL] scale). CTP-derived parameters of the frontal, temporal lobe and basal ganglia were calculated. Collateral index of the hypointensity ratio (HIR) was defined as a volume of Tmax >10 s/ Tmax >4 s.Results: Between December 2020 and December 2021, 21 MMD patients (15 bilateral cases and 6 unilateral cases, for a total of 36 hemispheres) were retrospectively included. Compared with the NH group, the IS group showed obviously abnormal hemodynamics. As for the primary outcomes, HIR showed an excellent area under the curve of 0.955 (95 % CI: 0.886-1.000, p < 0.001). Significant correlations were found between CTP-derived parameters and secondary outcomes. Furthermore, HIR was significantly correlated with mRS (r = 0.576, p = 0.001) and ADL scores (r = 0.644, p < 0.001).Conclusion: Among different imaging types, IS hemispheres were characterized by distinct changes of hemodynamic parameters. Collateral index of HIR could be considered a clinically accessible and promising indictor of functional and clinical outcomes in MMD.