To classify venous malformations based on contrast-enhanced MR angiography that may serve as a basis for treatment plan.

A retrospective analysis was performed in 58 patients with venous malformations who underwent contrast-enhanced MR angiography. Venous malformations were classified according to their venous drainage into: type I, isolated malformation without peripheral drainage; type II, malformation that drains into normal veins; type III, malformation that drains into dilated veins; and type IV, malformation that represents dysplastic venous ectasia. Image analysis was done by two reviewers. Intra and inter-observer agreement of both reviewers and intra-class correlation was done.

The intra-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for the first reviewer (k = 0.83, 95% CI = 0.724–0.951, P = 0.001) and substantial for the second reviewer (K = 0.79, 95% CI = 0.656-0.931, P = 0.001). The inter-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for both reviewers at the first time (K = 0.96, 95% CI = 0.933–1.000, P = 0.001) and second time (k = 0.81, 95% CI = 0.678–0.942, P = 0.001). There was high intra-class correlation of both reviewers for single measure (ICC = 0.85, 95% CI = 0.776–0.918, P = 0.001) and for average measures (ICC = 0.96, 95% CI = 0.933–0.978, P = 0.001).

Contrast-enhanced MR angiography classification of venous malformations may be a useful, simple and reliable tool to accurately classify venous malformation and this topographic classification helps for better management strategy.