Continuous blood flow visualization with laser speckle contrast imaging during neurovascular surgery

Abstract

. Significance: Laser speckle contrast imaging (LSCI) has emerged as a promising tool for intraoperative cerebral blood flow (CBF) monitoring because it produces real-time full-field blood flow maps noninvasively and label free. Aim: We aim to demonstrate the ability of LSCI to continuously visualize blood flow during neurovascular procedures. Approach: LSCI hardware was attached to the surgical microscope and did not interfere with the normal operation of the microscope. To more easily visualize CBF in real time, LSCI images were registered with the built-in microscope white light camera such that LSCI images were overlaid on the white light images and displayed to the neurosurgeon continuously in real time. Results: LSCI was performed throughout each surgery when the microscope was positioned over the patient, providing the surgeon with real-time visualization of blood flow changes before, during, and after aneurysm clipping or arteriovenous malformation (AVM) resection in humans. LSCI was also compared with indocyanine green angiography (ICGA) to assess CBF during aneurysm clipping and AVM surgery; integration of the LSCI hardware with the microscope enabled simultaneous acquisition of LSCI and ICGA. Conclusions: The results suggest that LSCI can provide continuous and real-time CBF visualization without affecting the surgeon workflow or requiring a contrast agent. The results also demonstrate that LSCI and ICGA provide different, yet complementary information about vessel perfusion.

Real-time laser speckle contrast imaging for intraoperative neurovascular blood flow assessment. Animal experimental study.

“…Laser-speckle contrast imaging (LSCI) is a promising method of intraoperative blood flow control during neurosurgical interventions 2 . LSCI calculates an indicator called speckle contrast, which is quantitatively related to the velocity of particles in a given field 3 . This fact allows us to determine the relative velocity of blood flow in each pixel of a given field and create a color image, the intensity of the color in which will characterize the relative velocity of blood flow.…”

Using pressure-driven flow systems to evaluate laser speckle contrast imaging

“…This has produced great interest in using LSCI for imaging flow in preclinical neuroscience research 3 – 6 as well as a broad set of clinical applications spanning the skin, 7 , 8 retina, 9 , 10 and brain 11 – 13 Efforts to improve the quantitative accuracy of LSCI resulted in the development of multi-exposure speckle imaging (MESI), 14 which offer more robust estimates of flow compared to traditional single-exposure LSCI 15 , 16 . The acquisition of data at multiple camera exposure times increases the dynamic range of flow sensitivity while the more comprehensive dynamic light scattering model better accounts for the presence of static scatterers and instrumentation factors.…”

Intraoperative laser speckle contrast imaging to visualize blood flow dynamics in neurosurgery

“…The technique offers full field, 2D blood flow images to the surgeon in real-time. The feasibility and potential of LSCI during neurosurgery has been shown by various groups highlighting the benefits and importance of incorporating the LSCI hardware components onto the surgical microscope 8,9 . Our custom-built imaging device enables blood flow visualization during critical moments of the surgery, which is key when evaluating the full potential of the technology as a continuous blood flow monitoring modality in neurosurgery.…”