Our group investigates the application of the clinically novel laser speckle contrast imaging. This technology helps surgeons assess tissue perfusion without the use of contrast dye, that is required with indocyanine green fluorescence. (Nwaiwu et al., 2023)
We have shown that subjecdtive interpretation of LSCI is equivalent to ICG in left-sided colorectal resections.(Skinner et al., 2024), and that objective quantification of LSCI is equivalent to quantification of ICG in pre-clinical porcine model. (Skinner et al., 2024)
References
2024
Dis Colon Rectum
Clinical Utility of Laser Speckle Contrast Imaging and Real-Time Quantification of Bowel Perfusion in Minimally Invasive Left-Sided Colorectal Resections
G. Skinner, Y. Liu, A. Harzman, and 8 more authors
BACKGROUND: Left-sided colorectal surgery demonstrates high anastomotic leak rates, with tissue ischemia thought to influence outcomes. Indocyanine green is commonly used for perfusion assessment, but evidence remains mixed for whether it reduces colorectal anastomotic leaks. Laser speckle contrast imaging provides dye-free perfusion assessment in real-time through perfusion heat maps and quantification. OBJECTIVE: This study investigates the efficacy of advanced visualization (indocyanine green versus laser speckle contrast imaging), perfusion assessment, and utility of laser speckle perfusion quantification in determining ischemic margins. DESIGN: Prospective intervention group using advanced visualization with case-matched, retrospective control group. SETTINGS: Single academic medical center. PATIENTS: Forty adult patients undergoing elective, minimally invasive, left-sided colorectal surgery. INTERVENTIONS: Intraoperative perfusion assessment using white light imaging and advanced visualization at 3 time points: T1—proximal colon after devascularization, before transection, T2—proximal/distal colon before anastomosis, and T3—completed anastomosis. MAIN OUTCOME MEASURES: Intraoperative indication of ischemic line of demarcation before resection under each visualization method, surgical decision change using advanced visualization, post hoc laser speckle perfusion quantification of colorectal tissue, and 30-day postoperative outcomes. RESULTS: Advanced visualization changed surgical decision-making in 17.5% of cases. For cases in which surgeons changed a decision, the average discordance between the line of demarcation in white light imaging and advanced visualization was 3.7 cm, compared to 0.41 cm (p=0.01) for cases without decision changes.There was no statistical difference between the line of ischemic demarcation using laser speckle versus indocyanine green (p=0.16). Laser speckle quantified lower perfusion values for tissues beyond the line ofischemic demarcation while suggesting an additional 1 cm of perfused tissue beyond this line. One (2.5%) anastomotic leak occurred in the intervention group. LIMITATIONS: This study was not powered to detect differences in anastomotic leak rates. CONCLUSIONS: Advanced visualization using laser speckle and indocyanine green provides valuable perfusion information that impacts surgical
Surg. Endosc.
Dye-less Quantification of Tissue Perfusion by Laser Speckle Contrast Imaging is Equivalent to Quantified Indocyanine Green in a Porcine Model
G. Skinner, M. Marois, J. Oberlin, and 3 more authors
Introduction: Subjective surgeon interpretation of near infrared perfusion video is limited by low interobserver agreement and poor correlation to clinical outcomes. In contrast, quantification of indocyanine green fluorescence video (Q-ICG) correlates with histologic level of perfusion as well as clinical outcomes. Measuring dye volume over time, however, has limitations; it’s not on-demand, has poor spatial resolution, and is not easily repeatable. Laser speckle contrast imaging quantification (Q-LSCI) is a real-time, dye free alternative, but further validation is needed. We hypothesize that Q-LSCI will distinguish ischemic tissue and correlate over a range of perfusion levels equivalent to Q-ICG. Methods: Nine sections of intestine in three swine were devascularized. Pairs of indocyanine green fluorescence imaging and laser speckle contrast imaging video were quantified within perfused, watershed, and ischemic regions. Q-ICG used normalized peak inflow slope. Q-LSCI methods were laser speckle perfusion units (LSPU), the base unit of laser speckle imaging, relative perfusion units (RPU), a previously described methodology which utilizes an internal control, and zero-lag normalized cross-correlation (X-Corr), to investigate if the signal deviations convey accurate perfusion information. We determine the ability to distinguish ischemic regions, and correlation to Q-ICG over a perfusion gradient. Results: All modalities distinguished ischemic from perfused regions of interest; Q-ICG values of 0.028 and 0.155 (p<0.001); RPU values of 0.15 and 0.68 (p<0.001); X-corr values of 0.73 and 0.24 (p<0.001). Over a range of perfusion levels, RPU had the best correlation with Q-ICG (r=0.79, p<0.001) compared with LSPU (r=0.74, p<0.001) and X-Corr (r=0.46, p<0.001). Conclusion: These results demonstrate that Q-LSCI discriminates ischemic from perfused tissue and represents similar perfusion information over a broad range of perfusion levels comparable to clinically validated Q-ICG. This suggests that Q-LSCI might offer clinically predictive real-time dye-free quantification of tissue perfusion. Further work should include validation in histologic studies and human clinical trials.
2023
JOGS
Real-time First-In-Human Comparison of Laser Speckle Contrast Imaging and ICG in Minimally Invasive Colorectal & Bariatric Surgery
Chibueze A. Nwaiwu, Christopher J. McCulloh, Garrett Skinner, and 4 more authors