PURPOSE: To evaluate a compact portable system for immediate automated postoperative ex-vivo analysis of urinary stone composition using Raman spectroscopy.
Analysis of urinary stone composition provides essential information for treatment and metaphylaxis of urolithiasis. Currently, infrared spectroscopy and x-ray diffraction are used for urinary stone analysis. However, these methods might require complex sample preparation and costly laboratory equipment. In contrast, Raman spectrometers might be simple and quick strategy for immediate stone analysis.
MATERIALS AND METHODS: Pure samples of 9 stone components, and 159 human urinary calculi were analysed by Raman spectroscopy using a microscope-coupled system at two different excitation wavelengths. Signal-to-noise ratio, peak positions and the distinctness of the acquired Raman spectra were analysed and compared. Background fluorescence was removed mathematically. Corrected Raman spectra were used as a reference library for automated classification of native human urinary stones (n=50). The results were then compared to standard infrared spectroscopy.
RESULTS: Signal-to-noise ratio was superior at an excitation wavelength of 532 nm. An automated, computer-based classifier was capable of matching spectra from patient samples with those of pure stone components. Consecutive analysis of 50 human stones showed a 100% sensitivity and specificity as compared to infrared spectroscopy (for components > 25%).
CONCLUSIONS: Our pilot study has indicated that Raman spectroscopy is a valid and reliable technique for determining urinary stone composition. Thus, we propose that the development of a compact and portable system based on Raman spectroscopy for immediate, postoperative stone analysis could represent an invaluable tool for metaphylaxis of urolithiasis.
Written by:
Miernik A, Eilers Y, Bolwien C, Lambrecht A, Hauschke D, Rebentisch G, Lossin PS, Hesse A, Rassweiler JJ, Wetterauer U, Schoenthaler M. Are you the author?
Department of Urology, University Medical Centre Freiburg, Hugstetterstr. 55, D-79106 Freiburg, Germany; Fraunhofer Institute for Physical Measurement Techniques, University Medical Centre Freiburg, Heidenhofstraße 8, D-79110 Freiburg, Germany.
Reference: J Urol. 2013 Jun 13. pii: S0022-5347(13)04612-0.
doi: 10.1016/j.juro.2013.06.024
PubMed Abstract
PMID: 23770149
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