The aim of this study is to evaluate the feasibility of assisted electromagnetic navigation in percutaneous echo-guided sclerotherapy of slow-flow vascular malformations. Feasibility will be defined in terms of the percentage of patients for whom the procedure is successful.

Primary interventional treatment of low flow vascular anomalies includes ultrasound guided foam sclerotherapy. Each procedure involves a percutaneous needle insertion. However, procedures remain complicated to obtain the right trajectory in order to inject the foam at the center of the abnormality. Electromagnetic navigation system tracks the operator's needle, meaning the position and progression of the needle is visualized in 3D real time on the ultrasound probe interface.

The present trial evaluate the feasibility of the electromagnetic navigation system during the needle insertion and the improvement of needle placement accuracy.

Inclusion Criteria:

• Low Flow Vascular Abnormality diagnosed by Duplex Ultrasound and MRI
• Decision of Ultrasound Guided Percutaneous Foam Sclerotherapy taken in multidisciplinary staff meeting

Exclusion Criteria:

• patients with pacemakers or internal defibrillator
• patients with ferromagnetic implanted material
• patients who are wards of court or under guardianship
• patients deprived of freedom by judicial or administrative decision
• patients under legal protection
• pregnant women