Limits...
Biophotonic endoscopy: a review of clinical research techniques for optical imaging and sensing of early gastrointestinal cancer.

Coda S, Siersema PD, Stamp GW, Thillainayagam AV - Endosc Int Open (2015)

Bottom Line: In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients.However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology.Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Imperial College London, London, United Kingdom ; Photonics Group, Department of Physics, Imperial College London, London, United Kingdom ; Endoscopy Unit, Department of Gastroenterology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom ; Department of Endoscopy, North East London NHS Treatment Centre, Care UK, London, United Kingdom.

ABSTRACT
Detection, characterization, and staging constitute the fundamental elements in the endoscopic diagnosis of gastrointestinal diseases, but histology still remains the diagnostic gold standard. New developments in endoscopic techniques may challenge histopathology in the near future. An ideal endoscopic technique should combine a wide-field, "red flag" screening technique with an optical contrast or microscopy method for characterization and staging, all simultaneously available during the procedure. In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients. However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology. This review describes some of the most recent applications of biophotonics in endoscopic optical imaging and metrology, along with their fundamental principles and the clinical experience that has been acquired in their deployment as tools for the endoscopist. Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

No MeSH data available.


Related in: MedlinePlus

Annotated photograph of the transportable trolley that houses the entire endoscopic spectrofluorometer, showing some important features of the fiberoptic fluorescence lifetime spectroscopy (FLS) system developed by the Photonics Group at Imperial College London. b The custom-built fiber probe for research use in gastrointestinal endoscopy (FiberTech GmbH, Berlin, Germany). c Annotated high-angle photograph illustrating the optical arrangement of the time-resolved spectrofluorometer with the lid removed. PMT, photomultiplier tube; ND, neutral density. (Source of acquisition: Endoscopy Unit, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.)
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4612244&req=5

FI158-8: Annotated photograph of the transportable trolley that houses the entire endoscopic spectrofluorometer, showing some important features of the fiberoptic fluorescence lifetime spectroscopy (FLS) system developed by the Photonics Group at Imperial College London. b The custom-built fiber probe for research use in gastrointestinal endoscopy (FiberTech GmbH, Berlin, Germany). c Annotated high-angle photograph illustrating the optical arrangement of the time-resolved spectrofluorometer with the lid removed. PMT, photomultiplier tube; ND, neutral density. (Source of acquisition: Endoscopy Unit, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.)

Mentions: Preliminary data from our group have shown a statistically significant decrease in 435-nm excited, spectrally averaged mean fluorescence lifetime (mean Δτ = – 570 ± 740 picoseconds, P = 0.021) in a comparison between normal tissue and neoplastic colonic polyps obtained from 12 patients undergoing colonoscopy as part of their clinical investigation. The shift in spectrally averaged mean fluorescence lifetime was found to be correlated with the shift in the emission spectrum (r2 = 0.71). Although the difference in the spectrally averaged mean lifetime shift between neoplastic and non-neoplastic polyps was not found to be statistically significant, if the changes in mean autofluorescence lifetime and emission wavelength of 435-nm excited fluorescence are combined, then a discrimination of neoplastic from non-neoplastic polyps with a sensitivity of 75 % and a specificity of 83 % is achieved. This study was undertaken with a compact, clinically compatible endoscopic fiberoptic coupled spectrofluorometer (Fig. 8) using all-solid-state picosecond diode lasers to provide simultaneous measurements of time-resolved fluorescence spectra with two excitation wavelengths (375 and 435 nm) 15.


Biophotonic endoscopy: a review of clinical research techniques for optical imaging and sensing of early gastrointestinal cancer.

Coda S, Siersema PD, Stamp GW, Thillainayagam AV - Endosc Int Open (2015)

Annotated photograph of the transportable trolley that houses the entire endoscopic spectrofluorometer, showing some important features of the fiberoptic fluorescence lifetime spectroscopy (FLS) system developed by the Photonics Group at Imperial College London. b The custom-built fiber probe for research use in gastrointestinal endoscopy (FiberTech GmbH, Berlin, Germany). c Annotated high-angle photograph illustrating the optical arrangement of the time-resolved spectrofluorometer with the lid removed. PMT, photomultiplier tube; ND, neutral density. (Source of acquisition: Endoscopy Unit, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4612244&req=5

FI158-8: Annotated photograph of the transportable trolley that houses the entire endoscopic spectrofluorometer, showing some important features of the fiberoptic fluorescence lifetime spectroscopy (FLS) system developed by the Photonics Group at Imperial College London. b The custom-built fiber probe for research use in gastrointestinal endoscopy (FiberTech GmbH, Berlin, Germany). c Annotated high-angle photograph illustrating the optical arrangement of the time-resolved spectrofluorometer with the lid removed. PMT, photomultiplier tube; ND, neutral density. (Source of acquisition: Endoscopy Unit, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.)
Mentions: Preliminary data from our group have shown a statistically significant decrease in 435-nm excited, spectrally averaged mean fluorescence lifetime (mean Δτ = – 570 ± 740 picoseconds, P = 0.021) in a comparison between normal tissue and neoplastic colonic polyps obtained from 12 patients undergoing colonoscopy as part of their clinical investigation. The shift in spectrally averaged mean fluorescence lifetime was found to be correlated with the shift in the emission spectrum (r2 = 0.71). Although the difference in the spectrally averaged mean lifetime shift between neoplastic and non-neoplastic polyps was not found to be statistically significant, if the changes in mean autofluorescence lifetime and emission wavelength of 435-nm excited fluorescence are combined, then a discrimination of neoplastic from non-neoplastic polyps with a sensitivity of 75 % and a specificity of 83 % is achieved. This study was undertaken with a compact, clinically compatible endoscopic fiberoptic coupled spectrofluorometer (Fig. 8) using all-solid-state picosecond diode lasers to provide simultaneous measurements of time-resolved fluorescence spectra with two excitation wavelengths (375 and 435 nm) 15.

Bottom Line: In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients.However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology.Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Imperial College London, London, United Kingdom ; Photonics Group, Department of Physics, Imperial College London, London, United Kingdom ; Endoscopy Unit, Department of Gastroenterology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom ; Department of Endoscopy, North East London NHS Treatment Centre, Care UK, London, United Kingdom.

ABSTRACT
Detection, characterization, and staging constitute the fundamental elements in the endoscopic diagnosis of gastrointestinal diseases, but histology still remains the diagnostic gold standard. New developments in endoscopic techniques may challenge histopathology in the near future. An ideal endoscopic technique should combine a wide-field, "red flag" screening technique with an optical contrast or microscopy method for characterization and staging, all simultaneously available during the procedure. In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients. However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology. This review describes some of the most recent applications of biophotonics in endoscopic optical imaging and metrology, along with their fundamental principles and the clinical experience that has been acquired in their deployment as tools for the endoscopist. Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

No MeSH data available.


Related in: MedlinePlus