Diagnostic potential of fluorescence of formalin-fixed paraffin-embedded malignant melanoma and pigmented skin lesions: quantitative study of fluorescence intensity using fluorescence microscope and digital imaging.

The background for this study was reports in the literature of stronger fluorescence observed visually for melanomas compared with benign naevi in formalin-fixed paraffin-embedded sections. Our objective was to carry out a quantitative study of the phenomenon and to investigate if such an approach could be used in the detection of melanomas. Microscopic digital imaging was used to measure quantitatively the fluorescence intensity in specimens from 50 malignant melanomas, four basal cell carcinomas and 58 benign lesions. The mean fluorescence intensity of the melanomas was considerably higher than of the other lesions. For melanomas, the intensity depended both on the distance from the skin surface and the distance from the centre of the lesion. A simple algorithm based on the intensity threshold correctly classified the melanomas with a sensitivity of 74% and a specificity of 59%. Quantitative measurements of the fluorescence of the pigmented skin lesions fixed with formalin and embedded in paraffin can be a useful auxiliary tool for differentiating melanoma from other pigmented lesions histopathologically.

Fluorescence in situ detection of human cutaneous melanoma: study of diagnostic parameters of the method.

Multicenter study of the diagnostic parameters was conducted by three groups in Poland to determine if in situ fluorescence detection of human cutaneous melanoma based on digital imaging of spectrally resolved autofluorescence can be used as a tool for a preliminary selection of patients at increased risk of the disease. Fluorescence examinations were performed for 7228 pigmented lesions in 4079 subjects. Histopathologic examinations showed 56 cases of melanoma. A sensitivity of fluorescence detection of melanoma was 82.7% in agreement with 82.5% found in earlier work. Using as a reference only the results of histopathologic examinations obtained for 568 cases we found a specificity of 59.9% and a positive predictive value of 17.5% (melanomas versus all pigmented lesions) or 24% (melanomas versus common and dysplastic naevi). The specificity and positive predictive value found in this work are significantly lower than reported earlier but still comparable with those reported for typical screening programs. In conclusion, the fluorescence method of in situ detection of melanoma can be used in screening large populations of patients for a selection of patients who should be examined by specialists.

Spectrally resolved fluorescence imaging of human colonic adenomas.

Native fluorescence (autofluorescence) of human tissues can be a valuable source of diagnostic information for detecting premalignant and malignant lesions in the human body. Digital imaging of autofluorescence may be useful for localization of such lesions during endoscopic examinations. Tissue fluorescence of 31 adenomatous polyps obtained from 16 patients has been excited in vitro using the 325 nm line of a He-Cd laser. Digital images of the autofluorescence are recorded in six spectral bands. This study provides new data about the spatial distributions of autofluorescence intensities emitted in different spectral bands by colonic adenomatous lesions and normal colonic mucosa. Areas characterized by autofluorescence intensity lower than in normal mucosa are found for a majority of the polyps under study. The observed patterns of spatial distribution differ for the different spectral bands and for different polypoid lesions. No inverse correlation is found between the emission intensity and the thickness of colonic mucosa. The results indicate the spectral bands most useful for diagnostic applications and demonstrate the complexity of the optical processes involved in shaping both the spectra and intensities of the autofluorescence.

Detection of colonic malignant lesions by digital imaging of UV laser-induced autofluorescence.

The objective of our study was to investigate whether digital imaging of autofluorescence could be applied in the detection of colonic malignancies. Autofluorescence was excited with a 325 nm line from a He-Cd laser. Images were recorded in vitro in six spectral bands. The material for study was 50 resected specimens for which images of 64 areas were recorded. The main result is the observation that for a majority of malignant and premalignant lesions the intensity of autofluorescence was lower than for the corresponding normal mucosa in all of the spectral bands selected for imaging. The spectral bands centered around 440 nm and 475 nm seem to be most promising in terms of possible future clinical applications.

Detection of melanomas by digital imaging of spectrally resolved ultraviolet light-induced autofluorescence of human skin.

Digital images of autofluorescence excited with 366 nm Hg line were recorded in a narrow 475 nm band for 408 pigmented lesions of the skin (90 melanomas, 205 common melanocytic and dysplastic naevi, 113 lesions of different kinds) and analysed photometrically with respect to spatial distribution of intensity to differentiate between melanomas and other melanocytic lesions. Earlier reports describing patterns of intensity distributions characteristic for melanomas have not been confirmed in this study. However, our evaluations showed that an algorithm based on ratios of maximum intensity recorded outside the lesions and minimum intensity found within them, allows melanomas to be detected with a sensitivity of 82.5%, a specificity of 78.6% and a positive predictive value of 58.9% (melanomas versus common and dysplastic naevi) or 76.7% (melanomas versus other pigmented lesions). The method is now being tested in a multicentre study involving three groups in three different cities in Poland.

Ultraviolet laser-induced fluorescence of human stomach tissues: detection of cancer tissues by imaging techniques.

BACKGROUND AND OBJECTIVE: The background for this work was several literature reports on applications of the fluorescence methods to detection and localization of human cancers. The objective of our study has been to investigate if such an approach could be applied for the detection of gastric cancers. STUDY DESIGN/MATERIALS AND METHODS: Our study was designed in such a way that spectrally resolved images of laser-induced fluorescence of human gastric mucosa were collected and assessed from a point of view of elaborating an algorithm allowing for a differentiation between malignant and premalignant lesions and areas of normal mucosa. The method involved exciting the autofluorescence with ultraviolet light (325 nm, He-Cd laser). The images were recorded in vitro in six regions of a visible spectrum using a cooled CCD camera. The material for study was 21 resected specimens for which altogether 72 surface areas were examined. RESULTS: The main result is the observation that a difference of the fluorescence intensities measured at 440 nm and 395 nm, both normalized to intensity measured at 590 nm, differs significantly for the tissues of interest. CONCLUSION: Using that difference as a diagnostic parameter, it was possible to classify malignant tumor tissues with a sensitivity of 96% and a predictive value of 42%, whereas the same approach applied to abnormal but not tumor stomach tissues gave values of 80%, and 98%, respectively.

Ultraweak chemiluminescence arising for glutaraldehyde-induced cross-linking reactions of biomolecules.

Chemiluminescence arising from cross-linking reactions of glutaraldehyde was examined. Our findings indicate that: (i) new reactions not yet described in the literature may be responsible for a part of the observed emissions; and (ii) this chemiluminescence may offer a new way of optimizing procedures of fixing biological materials prepared for microscopic examinations.

[Tissue spectroscopy. New generation of optical methods for cancer detection]. / Spektroskopia tkankowa. Nowa generacja optycznych metod wykrywania nowotworów.

Recent developments in the field of new, non-invasive, sensitive methods of cancer detection based on measurements of autofluorescence of cells are discussed. Research oriented on a detection of human cancer has been carried on by several groups for last six years only but has already yielded important data pointing to a possibility of both in situ and in vitro detection of cancerous tissues in several human organs, especially lung, gynecological tract, skin and gastro-intestinal tract. At least two such methods have been currently subject to clinical tests.