Early detection and differentiation of venous and arterial occlusion in skin flaps using visible diffuse reflectance spectroscopy and autofluorescence spectroscopy

Abstract

Our previous preclinical study demonstrated that both visible diffuse reflectance and autofluorescence spectroscopy, each of which yields a different set of physiological information, can predict skin flap viability with high accuracy in a MacFarlane rat dorsal skin flap model. In this report, we further evaluated our technique for the early detection and differentiation of venous occlusion and arterial occlusion in a rat groin flap model. We performed both diffuse reflectance and autofluorescence measurements on the skin flap model and statistically differentiated between flaps with and without occlusions as well as between flaps with venous occlusion and those with arterial occlusion based on these non-invasive optical measurements. Our preliminary results suggested that visible diffuse reflectance and autofluorescence spectroscopy can be potentially used clinically to detect both venous and arterial occlusion and differentiate one from the other accurately at an early time point.

Spectral diffuse reflectance and autofluorescence imaging can perform early prediction of blood vessel occlusion in skin flaps

“…The color/narrow‐band measurements and their respective ratios were further used to classify the flaps directly or after spectral reconstruction. Both diffuse reflectance and autofluorescence spectra of venously occluded flaps, arterially occluded flaps and control flaps have been published in our earlier paper , for which the point measurement study was conducted in parallel to this study on the same animals.…”

“…The calibration data set contains both color/narrow‐band measurements and the corresponding spectra for the same samples; while there are only color/narrow‐band measurements in the test data set. The data of full spectra were obtained in a parallel point measurement study , in which the full spectra of selected spots in the same regions of the same animals were measured by a compact spectrometer (USB4000, Ocean Optics, Florida, USA) coupled to a custom built fiber optic probe. A 405 nm laser (PhoxX ® 405‐120, Omicron, Germany) and a white light source (HL‐2000‐FHSA, Ocean Optics, Florida, USA) were used to yield autofluorescence and diffuse reflectance signals, respectively.…”

“…The whole data analysis procedure for coefficients and reconstructed spectra is similar to our parallel point measurement study . In short, partial least square (PLS) analysis was utilized to extract PLS components (PCs) to achieve data compression for both coefficients and reconstructed spectra after normalization, which yielded many PC scores.…”

“…Because diffuse reflectance and autofluorescence spectroscopy offer complementary information about tissue status, the combination of the two may be advantageous in terms of tissue assessment, which may yield more accurate tissue assessment. Although our parallel study focusing on point measurements of full optical spectra has demonstrated the success of using diffuse reflectance and autofluorescence spectroscopy in the detection of both venous and arterial occlusion, the common disadvantage of traditional optical spectroscopy is slow data acquisition when multiple locations need to be measured in a large tissue region. This is attributed to the employment of fiber‐optic probes in traditional optical spectroscopy, which can only perform point measurements.…”

Intraoperative video-rate hemodynamic response assessment in human cortex using snapshot hyperspectral optical imaging

“…3,4,[10][11][12][13][14] Prominent clinical applications of tissue optical spectroscopy include tissue wound healing monitoring 15,16 and brain hemodynamic assessment. 12,14,17,18 For each of these applications, a range of optical imaging techniques has been developed leading to tissue functional status information, either provided in absolute terms-i.e., by evaluating the concentration of the chromophores-or relative to a baseline value, oftentimes in terms of variations with respect to a signal detected at a specific time point.…”