Abstract Body: Background: Pediatric brain arteriovenous malformation (bAVM) patients often present with intracranial hemorrhage. While certain angioarchitectural features, such as aneurysms, deep venous drainage, a single draining vein, venous outflow stenosis, or small nidus size, increase hemorrhage risk, they do not fully predict it. Hemodynamic factors, particularly those assessed by quantitative color-coded digital subtraction angiography (cDSA), have also been linked to hemorrhage risk. This study evaluated the relationship between nidal mean transit time (MTT) and hemorrhage history in pediatric bAVM patients.

Methods: We retrospectively analyzed 40 pediatric bAVM patients using flow analysis software (syngo iFlow®; Siemens) to generate cDSA images. A neurointerventional radiologist identified regions of interest (ROIs) in each bAVM’s major arterial afferent and venous efferent. ROI peak time and MTT were obtained. ROI peak time was defined as the time that contrast intensity of the selected ROI reached the peak value and MTT was defined as the difference between venous and arterial peak times. Multivariable logistic regression analysis assessed the association between MTT and prior hemorrhage, adjusting for bAVM size.

Results: Among the 40 patients (median age 13 years ; 42.5% female), 47.5% (n=19) had a history of hemorrhage. The median bAVM size was 2.7 cm (IQR: 1.8-4.2), and the median nidal MTT was 0.97 seconds (IQR: 0.79-1.27). In logistic regression analysis, each 0.25-second increase in nidal MTT time was associated with a 24% reduction in the risk of prior hemorrhage (OR=0.76, 95% CI: 0.53-1.08, p=0.122), although not statistically significant. Larger bAVM size was significantly associated with a lower risk of prior hemorrhage (OR=0.48 per cm increase, 95% CI: 0.27-0.87, p=0.014).

Conclusion:
Our findings suggest that prolonged nidal MTT may be associated with a reduced risk of prior bleeding in pediatric bAVM patients after accounting for bAVM size. Larger bAVM size was significantly associated with a lower likelihood of prior hemorrhage.