ObjectiveOur purpose was to investigate the added diagnostic value of C-arm contrast-enhanced cone-beam CT (CE-CBCT) to routine contrast-enhanced MRI (CE-MRI) in detecting associated developmental venous anomalies (DVAs) in patients with sporadic intracranial cavernous malformations (ICMs).MethodsFifty-six patients (53 with single and three with double ICMs) met the inclusion criteria. All patients had routine CE-MRI scans performed at 1.5 Tesla. The imaging studies (CE-MRI and CE-CBCT) were retrospectively and independently reviewed by two observers, with consensus by a third. Group difference, intra- and interobserver agreement, and diagnostic performance of the modalities in detecting associated DVAs were calculated. Reference standard was CE-MRI.ResultsOn CE-MRI and CE-CBCT, 37 (66%; of 56) and 47 patients (84%; of 56) had associated DVAs, respectively. In 10 patients (52.6%; of CE-MRI negatives [n=19]), CE-CBCT improved the diagnosis. Nine patients (16%; of 56) had no DVA on both imaging techniques. Difference in proportions of associated DVAs on CE-MRI and CE-CBCT was statistically significant, p<0.05. Sensitivity, specificity, positive likelihood ratio, and area under the curve of CE-CBCT were 100% (95% confidence interval [CI]: 90.5-100%), 47.3% (95% CI: 24.4-71.1%), 1.9 (95%CI: 1.240-2.911), 0.737 (95%CI: 0.602-0.845), respectively. Intraobserver agreement was excellent for CE-MRI, kappa () coefficient =0.960, and CE-CBCT, =0.931. Interobserver agreement was substantial for CE-MRI, =0.803, and excellent for CE-CBCT, =0.810.ConclusionsCE-CBCT is a useful imaging technique especially in patients with negative routine CE-MRI in terms of detecting associated DVAs. In nearly half of these particular patients, it reveals an associated DVA as a new diagnosis.Key Points center dot Although it is known to be the gold standard, some of the DVAs associated with ICMs are underdiagnosed with CE-MRI.center dot In nearly half of the patients with negative routine CE-MRI, CE-CBCT reveals an associated DVA as a new diagnosis.center dot Intra- and interobserver agreement on CE-CBCT is excellent in terms of detecting associated DVAs.