Proof of Concept for the Application of Fluorescence Lifetime Imaging (FLIm) In Colorectal Surgery
EAES Academy. Keller D. 07/05/22; 363112; P157
Dr. Deborah Keller
Contributions
Contributions
Abstract
Introduction:
Fluorescence is a promising tool to improve surgical quality, but limitations in fluorophores, lack of sensitivity, and non-quantitative data with current platforms hamper utility. To address limitations, we developed an assessment technique using near-UV light that stimulates tissue autofluorescence- Fluorescence Lifetime Imaging (FLIm). FLIm detects dynamic spectral and temporal changes in tissue composition induced under pathological conditions. Benefits to FLIm from tissue autofluorescence include no need for exogenous contrast (label-free) and real-time data collection and visualization. Imaging is achieved with a sterilizable handheld probe that can be integrated with any operative platform. FLIm can discriminate between normal, malignant, fibrosed, and inflammatory tissue in humans and animal models. FLIm has been proven a sensitive intraoperative tool for solid brain and head and neck tumor delineation. There has been little application in gastrointestinal (GI) disease to date. The ability to discriminate normal from diseased tissue in the GI tract could add great value to current diagnostic and treatment practices.
The goal of this work was to establish the baseline of FLIm parameters (spectra and lifetime properties) in murine GI tissue. We hypothesized that FLIm technology would be adaptable to GI surgery with reproducible results.
Methods:
The colorectum, ileum, and mesentery of 12 healthy mice (6 male, 6 female) were collected after necropsy and imaged with FLIm. The FLIm employed a raster-scanned optical fiber probe (400µm diameter) for multispectral imaging over the visible spectrum (ch1=390/18nm, connective tissue target; ch2=435/40nm, NAD(P)H target; ch3=542/10nm, FAD target; and ch4=610/70nm, lipids/ porphyrins target). Channels were tuned to capture fluorescence from structural proteins collagen and elastin, cellular metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), lipids, and porphyrins.
Results:
On average, murine colorectal, ileal, and mesentery tissue exhibited distinct fluorescence lifetime in a spectrally dependent manner. At an individual level, colon and ileum samples presented a mid-section with longer lifetimes than the proximal and distal ends, from different arrangements in connective tissue. The mesentery had distinct areas with lifetime corresponding to simple mesenteric tissue, lymphovascular tissue, and interstitial fat. The patterns were consistent across gender and reproducible across subjects.
Conclusion:
Fluorescence lifetime imaging (FLIm) was successfully adapted to GI tissue, defining the spectral and lifetime properties in a healthy animal model. With the feasibility proven in the GI tract, next steps will be determining the sensitivity of FLIm in colorectal disease states and human validation as an intraoperative guidance tool during colorectal surgery.
Fluorescence is a promising tool to improve surgical quality, but limitations in fluorophores, lack of sensitivity, and non-quantitative data with current platforms hamper utility. To address limitations, we developed an assessment technique using near-UV light that stimulates tissue autofluorescence- Fluorescence Lifetime Imaging (FLIm). FLIm detects dynamic spectral and temporal changes in tissue composition induced under pathological conditions. Benefits to FLIm from tissue autofluorescence include no need for exogenous contrast (label-free) and real-time data collection and visualization. Imaging is achieved with a sterilizable handheld probe that can be integrated with any operative platform. FLIm can discriminate between normal, malignant, fibrosed, and inflammatory tissue in humans and animal models. FLIm has been proven a sensitive intraoperative tool for solid brain and head and neck tumor delineation. There has been little application in gastrointestinal (GI) disease to date. The ability to discriminate normal from diseased tissue in the GI tract could add great value to current diagnostic and treatment practices.
The goal of this work was to establish the baseline of FLIm parameters (spectra and lifetime properties) in murine GI tissue. We hypothesized that FLIm technology would be adaptable to GI surgery with reproducible results.
Methods:
The colorectum, ileum, and mesentery of 12 healthy mice (6 male, 6 female) were collected after necropsy and imaged with FLIm. The FLIm employed a raster-scanned optical fiber probe (400µm diameter) for multispectral imaging over the visible spectrum (ch1=390/18nm, connective tissue target; ch2=435/40nm, NAD(P)H target; ch3=542/10nm, FAD target; and ch4=610/70nm, lipids/ porphyrins target). Channels were tuned to capture fluorescence from structural proteins collagen and elastin, cellular metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), lipids, and porphyrins.
Results:
On average, murine colorectal, ileal, and mesentery tissue exhibited distinct fluorescence lifetime in a spectrally dependent manner. At an individual level, colon and ileum samples presented a mid-section with longer lifetimes than the proximal and distal ends, from different arrangements in connective tissue. The mesentery had distinct areas with lifetime corresponding to simple mesenteric tissue, lymphovascular tissue, and interstitial fat. The patterns were consistent across gender and reproducible across subjects.
Conclusion:
Fluorescence lifetime imaging (FLIm) was successfully adapted to GI tissue, defining the spectral and lifetime properties in a healthy animal model. With the feasibility proven in the GI tract, next steps will be determining the sensitivity of FLIm in colorectal disease states and human validation as an intraoperative guidance tool during colorectal surgery.
Introduction:
Fluorescence is a promising tool to improve surgical quality, but limitations in fluorophores, lack of sensitivity, and non-quantitative data with current platforms hamper utility. To address limitations, we developed an assessment technique using near-UV light that stimulates tissue autofluorescence- Fluorescence Lifetime Imaging (FLIm). FLIm detects dynamic spectral and temporal changes in tissue composition induced under pathological conditions. Benefits to FLIm from tissue autofluorescence include no need for exogenous contrast (label-free) and real-time data collection and visualization. Imaging is achieved with a sterilizable handheld probe that can be integrated with any operative platform. FLIm can discriminate between normal, malignant, fibrosed, and inflammatory tissue in humans and animal models. FLIm has been proven a sensitive intraoperative tool for solid brain and head and neck tumor delineation. There has been little application in gastrointestinal (GI) disease to date. The ability to discriminate normal from diseased tissue in the GI tract could add great value to current diagnostic and treatment practices.
The goal of this work was to establish the baseline of FLIm parameters (spectra and lifetime properties) in murine GI tissue. We hypothesized that FLIm technology would be adaptable to GI surgery with reproducible results.
Methods:
The colorectum, ileum, and mesentery of 12 healthy mice (6 male, 6 female) were collected after necropsy and imaged with FLIm. The FLIm employed a raster-scanned optical fiber probe (400µm diameter) for multispectral imaging over the visible spectrum (ch1=390/18nm, connective tissue target; ch2=435/40nm, NAD(P)H target; ch3=542/10nm, FAD target; and ch4=610/70nm, lipids/ porphyrins target). Channels were tuned to capture fluorescence from structural proteins collagen and elastin, cellular metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), lipids, and porphyrins.
Results:
On average, murine colorectal, ileal, and mesentery tissue exhibited distinct fluorescence lifetime in a spectrally dependent manner. At an individual level, colon and ileum samples presented a mid-section with longer lifetimes than the proximal and distal ends, from different arrangements in connective tissue. The mesentery had distinct areas with lifetime corresponding to simple mesenteric tissue, lymphovascular tissue, and interstitial fat. The patterns were consistent across gender and reproducible across subjects.
Conclusion:
Fluorescence lifetime imaging (FLIm) was successfully adapted to GI tissue, defining the spectral and lifetime properties in a healthy animal model. With the feasibility proven in the GI tract, next steps will be determining the sensitivity of FLIm in colorectal disease states and human validation as an intraoperative guidance tool during colorectal surgery.
Fluorescence is a promising tool to improve surgical quality, but limitations in fluorophores, lack of sensitivity, and non-quantitative data with current platforms hamper utility. To address limitations, we developed an assessment technique using near-UV light that stimulates tissue autofluorescence- Fluorescence Lifetime Imaging (FLIm). FLIm detects dynamic spectral and temporal changes in tissue composition induced under pathological conditions. Benefits to FLIm from tissue autofluorescence include no need for exogenous contrast (label-free) and real-time data collection and visualization. Imaging is achieved with a sterilizable handheld probe that can be integrated with any operative platform. FLIm can discriminate between normal, malignant, fibrosed, and inflammatory tissue in humans and animal models. FLIm has been proven a sensitive intraoperative tool for solid brain and head and neck tumor delineation. There has been little application in gastrointestinal (GI) disease to date. The ability to discriminate normal from diseased tissue in the GI tract could add great value to current diagnostic and treatment practices.
The goal of this work was to establish the baseline of FLIm parameters (spectra and lifetime properties) in murine GI tissue. We hypothesized that FLIm technology would be adaptable to GI surgery with reproducible results.
Methods:
The colorectum, ileum, and mesentery of 12 healthy mice (6 male, 6 female) were collected after necropsy and imaged with FLIm. The FLIm employed a raster-scanned optical fiber probe (400µm diameter) for multispectral imaging over the visible spectrum (ch1=390/18nm, connective tissue target; ch2=435/40nm, NAD(P)H target; ch3=542/10nm, FAD target; and ch4=610/70nm, lipids/ porphyrins target). Channels were tuned to capture fluorescence from structural proteins collagen and elastin, cellular metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), lipids, and porphyrins.
Results:
On average, murine colorectal, ileal, and mesentery tissue exhibited distinct fluorescence lifetime in a spectrally dependent manner. At an individual level, colon and ileum samples presented a mid-section with longer lifetimes than the proximal and distal ends, from different arrangements in connective tissue. The mesentery had distinct areas with lifetime corresponding to simple mesenteric tissue, lymphovascular tissue, and interstitial fat. The patterns were consistent across gender and reproducible across subjects.
Conclusion:
Fluorescence lifetime imaging (FLIm) was successfully adapted to GI tissue, defining the spectral and lifetime properties in a healthy animal model. With the feasibility proven in the GI tract, next steps will be determining the sensitivity of FLIm in colorectal disease states and human validation as an intraoperative guidance tool during colorectal surgery.
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