Journal Article

Intraoperative cerebral angiosonography with ultrasound contrast agents: how I do it

Saini, Marco, Del Bene, Massimiliano, Prada, Francesco, DiMeco, Francesco, Ferroli, Paolo

2015

Overview

Background Intraoperative vessel visualization is highly desirable, especially when the target is related to or close to main vessels, such as in the skull base and vascular surgery. Contrast-enhanced ultrasound (CEUS) is an imaging technique that allows visualization of tissue perfusion and vascularization through the infusion of purely intravascular ultrasound contrast agents (UCA). Methods After cerebral scanning with B-mode ultrasound (US) CEUS is performed, UCA are injected and insonated with low mechanical index US. A UCA-specific harmonic signal is transduced using a contrast-specific algorithm to obtain real-time angiosonography (ASG). Conclusions Real-time intraoperative ASG is a rapid, reliable, repeatable method for vessel visualization and evaluation of tissue perfusion. Key points • ASG permits to assess vessel position, dimension, and relationships; it also allows a qualitative evaluation of flow entity and direction. • ASG shows vessels in depth without the need of their direct exposure, as for fluorescence-guided surgery. • ASG permits to study the entire vascular tree without the necessity to set gain or pulse repetition frequency as in Doppler imaging. • Vessels of interest can be visualized following their entire length across the surgical field, along the arterial, capillary, and venous districts. • ASG scan is repeatable multiple times throughout the operation, and each exam could be recorded as a clip to be visualized at a later stage. • In case of neoplastic lesion, ASG characterizes the perfusion pattern in three phases: arterial, venous, and parenchymal, permitting to visualize afferent and efferent vessels, facilitating the surgical strategy. • During tumor debulking, ASG shows the remaining distance to major vessels, providing information to avoid direct vessel damage. • In tumor and AVM surgery, ASG shows nidus or tumoral remnants that might be covered by healthy tissue, thus not visible on the surface. • In case of aneurysm surgery, post-clipping angiosonographic control confirms proper aneurysm exclusion and distal vessels flow.

• Publisher: Springer Vienna,Springer Nature B.V
• Subject: Brain - blood supply / Cerebral Arteries - diagnostic imaging / Cerebral Veins - diagnostic imaging / Contrast Media / How I Do it - Neurosurgical Techniques / Humans / Interventional Radiology / Medicine / Medicine & Public Health / Minimally Invasive Surgery / Monitoring, Intraoperative - methods / Neurology / Neuroradiology / Neurosurgery / Surgical Orthopedics / Ultrasonography