"Combined use of Color-doppler ultrasound and Contrast-enhanced Ultrasound in the intraoperative armamentarium for AVM surgery".

BACKGROUND: Safety and efficacy in surgical treatment of cerebral arteriovenous malformations (AVMs) are dictated by thorough understanding of angioarchitectural features, intraoperative identification of feeding vessels and appreciation of surrounding eloquent areas. Our aim was to describe the preliminary results of combined application of Color Doppler Ultrasound (CDUS) and Contrast Enhanced Ultrasound (CEUS) in a consecutive surgical series of AVM. We pointed out the tool's efficacy in distinguishing feeding from bystander vessels, and in identifying pattern of venous drainage. We examined its role as an adjunct for semiquantitative evaluation of the nidus inflow.

METHODS: We used combined CDUS and CEUS in patients surgically treated for cerebral AVMs. We adopted these techniques following a designed protocol to guide safer AVM resection as an adjunct to Indocyanine green videoangiography. Intraoperative assessment by ultrasound was performed prior to, during and following nidus resection.

RESULTS: Four surgically treated cerebral AVMs availed of the ultrasound protocol. Post-operative conventional angiography showed complete resection of the AVMs. CDUS and CEUS proved to be valuable adjunctive tools to Indocyanine green videoangiography and micro-Doppler in properly navigating and discerning vascular structures, especially vessel feeders from bystanders. The protocol allows to identify flow direction, estimate blood velocity within the nidus and appreciate flow modifications following temporary clipping. Ultimately, it allows to evaluate the degree of nidus deafferentation, residual flow, restoration of venous drainage and absence of arteriovenous shunts.

CONCLUSIONS: The CDUS and CEUS protocol proved to be safe, repeatable and works as real time imaging further supporting complete surgical resection of AVMs.