Improvement of the specificity of cancer detection by autofluorescence imaging in the tracheo-bronchial tree using backscattered violet light

Gabrecht, Tanja; Radu, Alexandre; Grosjean, Pierre; Weber, Bernd; Reichle, Günther; Freitag, Lutz; Monnier, Philippe; van den Bergh, Hubert; Wagnières, Georges

doi:10.1016/j.pdpdt.2008.01.005

« Previous Next »Photodiagnosis and Photodynamic Therapy
Volume 5, Issue 1 , Pages 2-9, March 2008

Improvement of the specificity of cancer detection by autofluorescence imaging in the tracheo-bronchial tree using backscattered violet light

Tanja Gabrecht
- Swiss Federal Institute of Technology (EPFL), Laboratory for Air and Soil Pollution, Station 6, Building CH, 1015 Lausanne, Switzerland
Alexandre Radu
- The CHUV University Hospital, ENT Department, 1011 Lausanne, Switzerland
Pierre Grosjean
- The CHUV University Hospital, ENT Department, 1011 Lausanne, Switzerland
Bernd Weber
- Richard Wolf Endoscopes GmbH, 75438 Knittlingen, Germany
Günther Reichle
- Clinic for Pneumology and Thoracic Surgery Hemer, Pneumology Department, 58675 Hemer, Germany
Lutz Freitag
- Clinic for Pneumology and Thoracic Surgery Hemer, Pneumology Department, 58675 Hemer, Germany
Philippe Monnier
- The CHUV University Hospital, ENT Department, 1011 Lausanne, Switzerland
Hubert van den Bergh
- Swiss Federal Institute of Technology (EPFL), Laboratory for Air and Soil Pollution, Station 6, Building CH, 1015 Lausanne, Switzerland
Georges Wagnières, PhD
- Swiss Federal Institute of Technology (EPFL), Laboratory for Air and Soil Pollution, Station 6, Building CH, 1015 Lausanne, Switzerland
- Corresponding author. Tel.: +41 21 693 3120; fax: +41 21 693 3626.

published online 21 February 2008.

Summary

Background

Autofluorescence bronchoscopy (AFB) is a highly sensitive tool for the detection of early bronchial cancers. However, its specificity remains limited due to primarily false positive results induced by hyperplasia, metaplasia and inflammation. We have investigated the potential of blue-violet backscattered light to eliminate false positive results during AFB in a clinical pilot study.

Methods

The diagnostic autofluorescence endoscopy (DAFE) system was equipped with a variable band pass filter in the imaging detection path. The backscattering properties of normal and abnormal bronchial mucosae were assessed by computing the contrast between the two tissue types for blue-violet wavelengths ranging between 410 and 490nm in 12 patients undergoing routine DAFE examination. In a second study including 6 patients we used a variable long pass (LP) filter to determine the spectral design of the emission filter dedicated to the detection of this blue-violet light with the DAFE system.

Results

(Pre-)neoplastic mucosa showed a clear wavelength dependence of the backscattering properties of blue-violet light while the reflectivity of normal, metaplastic and hyperplastic autofluorescence positive mucosa was wavelength independent.

Conclusions

Our results showed that the detection of blue-violet light has the potential to reduce the number of false positive results in AFB. In addition we determined the spectral design of the emission filter dedicated to the detection of this blue-violet light with the DAFE system.

Keywords: Autofluorescence bronchoscopy, Backscattered blue-violet light, Specificity, Optical design, DAFE, CIS