An algorithm for calculi segmentation on ureteroscopic images.
OBJECTIVE
The purpose of the study is to develop an algorithm for the segmentation of renal calculi on ureteroscopic images. In fact, renal calculi are common source of urological obstruction, and laser lithotripsy during ureteroscopy is a possible therapy. A laser-based system to sweep the calculus surface and vaporize it was developed to automate a very tedious manual task. The distal tip of the ureteroscope is directed using image guidance, and this operation is not possible without an efficient segmentation of renal calculi on the ureteroscopic images.


METHODS
We proposed and developed a region growing algorithm to segment renal calculi on ureteroscopic images. Using real video images to compute ground truth and compare our segmentation with a reference segmentation, we computed statistics on different image metrics, such as Precision, Recall, and Yasnoff Measure, for comparison with ground truth.


RESULTS
The algorithm and its parameters were established for the most likely clinical scenarii. The segmentation results are encouraging: the developed algorithm was able to correctly detect more than 90% of the surface of the calculi, according to an expert observer.


CONCLUSIONS
Implementation of an algorithm for the segmentation of calculi on ureteroscopic images is feasible. The next step is the integration of our algorithm in the command scheme of a motorized system to build a complete operating prototype.
Rosa
Benoît
B
UPMC Univ Paris 06, UMR 7222, ISIR, 75005, Paris, France. benoit.rosa@centraliens.net
Mozer
Pierre
P
Szewczyk
Jérôme
J
D000465:Algorithms; D003116:Color; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007669:Kidney Calculi / Q000175:diagnosis* / Q000628:therapy; D007834:Lasers; D017602:Lithotripsy, Laser; D018666:Ureteroscopy / Q000295:instrumentation / Q000379:methods*; D014741:Video Recording