Sclerotherapy for venous malformations using a "negative subtraction" technique.

We describe a technique of injecting alcohol into venous malformations (VM) under slow digital subtraction angiography (DSA) which eliminates the need to pre-mix the alcohol with a contrast agent. The technique presented here is especially helpful when Metrizamide is not available or not permitted for use. It offers an elegant way to visualize, in real time, the alcohol injected into the VM, while preserving its high concentration and potency as a sclerosing agent.