1145. Laser Speckle Contrast Imaging for Visualizing Blood Flow During Cerebral Aneurysm Surgery: Comparison with Indocyanine-Green Angiography

Authors: David Miller; Colin Sullender, PhD; Andrew Dunn, PhD; Ramsey Ashour, MD (AUSTIN, TX)

Introduction:

Cerebral blood flow (CBF) monitoring is crucial during cerebrovascular surgery to inform decision making. In cerebral aneurysm clipping cases, Indocyanine-Green Angiography (ICGA) is routinely used to confirm patency in vessels and determine successful aneurysmal obliteration. The optical imaging technique laser speckle contrast imaging (“Speckle”) has emerged as a promising tool to monitor CBF because it produces real-time full-field blood flow maps non-invasively and label-free, providing a potential continuous monitoring solution.

Methods:

A laser, camera, and imaging optics were integrated into a Leica M530 OH6 surgical microscope to perform Speckle during cerebral aneurysm surgery. The hardware did not interfere with the sterile draping of the microscope or normal operation of the microscope. The laser was controlled remotely such that Speckle could be performed any time when the microscope was positioned over the patient. All n=3 surgeries were performed at Dell Seton Medical Center at the University of Texas at Austin by the neurosurgical co-investigator (R.A.). Speckle was performed at multiple time points throughout each surgery, and Speckle and ICGA were performed simultaneously as a comparison to visualize CBF.

Results:

We present videos comparing Speckle and ICGA after aneurysm clippings. Additionally, we demonstrate Speckle’s ability to continuously monitor CBF in real-time during critical surgical procedures, such as during aneurysm clipping.  We demonstrate Speckle’s ability to assess changes in CBF in the aneurysm and surrounding vessels before, during, and after aneurysm clipping.

Conclusion:

Our results demonstrate that Speckle and ICGA are complementary tools for visualizing CBF to aid surgical decision making. Both Speckle and ICGA can be used to determine perfusion in a vessel. An advantage of Speckle is it provides continuous monitoring of CBF without interrupting the surgical work-flow and does not require a contrast agent.