Fluorescence Spectroscopy as a Tool for the Assessment of Liver Samples with Several Stages of Fibrosis.

BACKGROUND: During the last years, fluorescence spectroscopy has been used as a potential tool for the evaluation and characterization of tissues with different disease conditions due to its low cost, high sensitivity, and minimally or noninvasive character. OBJECTIVE: In this study, fluorescence spectroscopy was used to study 19 paraffin blocks containing human liver tissue from biopsies. METHODS AND RESULTS: All samples were previously analyzed by two senior pathologists in a single-blind trial. After their evaluation, four liver samples were classified as nonfibrosis (F0), four as initial fibrosis (F1-F2), four as advanced fibrosis (F3), and six as cirrhosis (F4). The fluorescence was induced at different wavelengths as follows: 330, 365, and 405 nm using a portable fiber-optic system. The fluorescence spectra were recorded in the range of 400-750 nm. A distinctive correlation between the shape of each spectrum and the level of fibrosis in the liver sample was detected. A multi-variate statistical analysis based on principal component analysis followed by linear discrimination analysis was applied to develop algorithms able to distinguish different stages of fibrosis based on the characteristics of fluorescence spectra. Pairwise comparisons were performed: F0 versus F1-F2, F1-F2 versus F3, F3 versus F4, and F1-F2 versus F4. The algorithms applied to each set of data yielded values of sensitivity and specificity that were higher than 90% and 95%, respectively, in all the analyzed cases. CONCLUSIONS: With this study, it is concluded that fluorescence spectroscopy can be used as a complementary tool for the assessment of liver fibrosis in liver tissue samples, which sets the stage for subsequent clinical trials.

Spectroscopic and Imaging Characteristics of Pigmented Non-Melanoma Skin Cancer and Melanoma in Patients with Skin Phototypes III and IV.

INTRODUCTION: Non-melanoma skin cancer is the most common malignancy worldwide. Differentiating between malignant and benign skin tumors, however, can be challenging. As a result, various auxiliary tools have been developed to aid in the diagnosis of cutaneous neoplasms. Here, skin tumors were investigated through analysis of their digital image histograms and spectroscopic response under ultraviolet (UV) and white light-emitting diodes (LEDs). METHODS: Fifty tumoral lesions were spectroscopically and histologically studied. For optical studies, UV at 375 nm and white LEDs were used to illuminate the lesions. Commercial cameras were used for imaging, and a miniature spectrometer with a bifurcated optical fiber was used for spectroscopic measurements. RESULTS: In this study, the intensity histograms of the images taken under white and UV illumination and the spectroscopic response under white light showed clear differences between pigmented basal cell carcinoma (BCC), intradermal melanocytic nevus (IDN), and melanoma lesions for skin phototypes III and IV. However, there was little difference in their spectroscopic response to the UV LED. CONCLUSION: We found differences in the intensity and shape of diffuse reflectance spectra of pigmented BCC, IDN, and melanoma lesions in patients with skin phototypes III and IV. Also, images taken under UV and white light were helpful for differentiation of these pigmented lesions. Additional research is needed to ascertain the clinical utility of these tools for skin cancer diagnosis.