2. UroToday Home
  3. Recent Abstracts
  4. Endourology & Urolithiasis
  5. Minimally Invasive Procedures

EAU 2018: Raman Spectroscopy Analysis of Urolithiasis Composition in Biological Environments: Feasibility Study and Preliminary Results

Copenhagen, Denmark (UroToday.com) Dr. Pradere, clinical urologist from the CHU Tours in Tours, France, presented his findings on the use of Raman spectroscopy for the analysis of stone composition in a biological environment. It is commonly known that diagnostic analysis of urolithiases following treatment for stone disease is the keystone for determining postoperative planning for future disease prevention. Currently, the gold standard technique of stone composition analysis is infrared spectroscopy (IRS). Under current urological guidelines, it is recommended that all surgeons perform this test for primary stone formers. Dr. Pradere suggests an approach that may potentially rival IRS for the classification of renal stones while in a urinary environment.

To test this method, the researchers obtained a set of more than one thousands stones and analyzed them using the gold standard, IRS technique. This was done in order to obtain a group of pure stones that consisted of greater than 85% of the same composition. These stones would then be used in a Raman spectroscopy setup with a microscope combination. A 785 nm wavelength laser was used during the technique. To begin the procedure, the analysis took place in air to obtain the basic spectral characteristics of each stone. Then, the stones were moved into a natural urine and urine diluted to 50% and the procedure was repeated.

Of the stones tested, 7 different classes were identified including weddellite, whewellite, struvite, brushite, carbapitite, cysteine, and uric acid. The Raman spectroscopy carried out in the air produced the most intense spectra since there was no medium to block the laser. The lowest intensity spectra came from the natural urine while there was a significant increase in spectra intensity in the 50% diluted urine. Additionally, brushite stones had the worst signal in the Raman spectroscopy, and spectra carried out in the presence of blood clots increased background noise. Also, the distance between the laser and the stone impacted intensity; the signal was maximized when the fiber was in contact with the stone. Finally, all spectra were obtained within 20 seconds.

In his closing remarks, Dr. Pradere discussed how Raman spectroscopy for analysis of stone composition in urine is feasible and producible. These results show great promise as a future application of clinical endoscopic use to determine the chemical composition of stones in vivo during surgery to make a diagnosis. After diagnosis is obtained, the laser setting can be easily manipulated to then proceed with destruction of the stone.

Speaker: B. Pradere

Authors: Pradere B., Lucas I., Abi Haidar D. , Doizi S., Daudon M., Traxer O.

Written by: Zachary Valley, Department of Urology, University of California-Irvine, at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark