Lesion filling index predicts brain arteriovenous malformation obliteration after Gamma knife radiosurgery: a hemodynamic analysis.

Abstract

Hemodynamics significantly influences the clinical outcomes of brain arteriovenous malformations (AVM). This study aimed to determine if the lesion filling index (LFI), obtained via quantitative digital subtraction angiography (QDSA), can predict complete complete obliteration after Gamma knife radiosurgery (GKRS). We retrospectively reviewed AVM patients who underwent GKRS and DSA exams from 2011 to 2021. Clinical, angioarchitectural, and QDSA hemodynamic features were analyzed. The LFI, derived from QDSA, was evaluated as a predictor of complete complete obliteration post-SRS using Cox proportional hazards and Kaplan-Meier analyses. Among 118 AVMs with a mean follow-up of 5.76 ± 2.76 years, post-SRS complete obliteration was linked to reduced nidus volume (7.27 ± 12.3 vs. 19.2 ± 35.7 mm³, p = 0.049), smaller nidus diameter (26.0 ± 14.9 vs. 34.1 ± 19.8 mm, p = 0.015), and absence of feeding artery dilation (21.1% vs. 46.3%, p = 0.008). Higher Arterial Diagnostic Window (ADW) (972.27 ± 1615.53 vs. 515.29 ± 730.26, p = 0.036), higher LFI (905.31 ± 2288.37 vs. 249.65 ± 1092.46, p = 0.037), and lower Transnidal Relative Velocity (TRV), a parameter defined as the maximum diameter of AVM divided by the full width at half maximum (74.31 ± 95.67 vs. 137.80 ± 152.01, p = 0.021), were also associated with complete obliteration. After adjusting for confounders, only two variables-absence of feeding artery dilation (HR 0.35, 95%CI 0.16-0.78, p = 0.010) and higher LFI (HR 1.00, 95%CI 1.00-1.00, p = 0.006) remained significant predictors. The ROC curve identified 188.4 as the LFI cutoff, and Kaplan-Meier analysis confirmed LFI's predictive value (log-rank test, χ² = 12.776, p < 0.001). Elevated LFI and absence of feeding artery dilation predict AVM complete obliteration after GKRS, indicating that overfilling and low blood flow in the nidus may promote complete obliteration.