DETERMINATION OF INDWELLING URETERAL STENT PATENCY - COMPARISON OF STANDARD CONTRAST AND NUCLEAR CYSTOGRAPHY, AND LASIX RENOGRAPHY

Objective. Because of the difficulty in determining patency of Double-J ureteral catheters, a study was devised at Madigan Army Medical Center to determine the best method to demonstrate stented ureteral patency. Methods. Forty-two patients requiring Double-J ureteral stenting for various clinical reasons were the study group. Outpatients underwent contrast retrograde cystography, nuclear cystography, and diuretic renography every four to six weeks during the stent duration or just prior to stent removal if the stents were indwelling for less than four weeks. In addition, four weeks after stent removal diuretic renography alone was done to evaluate for possible delayed obstructive effect of the ureteral stenting. Results. A total of 53 stents and 42 patients were evaluated. Seventy-seven sets of studies were obtained. In only four instances did all three imaging methods agree on the obstruction. In the remaining 73 sets of data, at least one imaging technique indicated stented ureteral patency. The contrast retrograde cystogram was positive for reflux 52 times (71 %). Nuclear cystography showed patency 54 times (74%) and an unobstructed diuretic renogram was obtained 59 times (81 %). In addition, five of the six diuretic renograms accomplished with patients in the supine position only and which showed obstruction were repeated with patients in the upright position, and they showed unobstructed function. The overall sensitivity for diuretic renography was 89 percent when the diuretic renogram was done with patients in the supine and upright positions. Conclusions. Diuretic renography is the most sensitive test for detecting stented ureteral patency. This test needs to be performed with patients in both the supine and upright positions.