Diagnostic Value of Color Doppler Ultrasonography of UPJ Obstruction

Huh, Jung Sik; Chang, Sung Goo; Kim, Jin Il

Abstract

The cause of ureteropelvic junction obstruction(UPJ) is almost due to intrinsic factor. But a small percentage of UPJ obstruction have extrinsic obstruction as a result of a crossing renal aberrant vessel. The diagnosis of UPJ obstruction by aberrant vessel is usually made at surgery because the urographic findings are nonspecific and difficult to find cause. For the purpose of detecting aberrant vessel as a cause of UPJ obstruction, authors examined 20 patients with color Doppler ultrasonographic equipment, then cause of obstruction was confirmed at the time of surgery, from July 1991 to February 1994. In seven of twenty patients aberrant vessel was detected by color Doppler ultrasonographic equipment. Among the seven patients, only three cases were caused directly by aberrant vessel, color Doppler examination disclosed a vessel or vessels at the tapering distal end of UPJ. In other two patients, aberrant vessel was detected but it was not direct cause of UPJ obstruction. Even in two of seven patients, aberrant vessel was not detected at the time of surgery. However in one of thirteen patients with no color Doppler signal at the UPJ, aberrant vessel was confirmed in surgical field. Sensitivity was 75 % and specificity was 75 % as detecting aberrant vessel by color Doppler ultrasonographic equipment. We believe that color Doppler examination is a useful method in demonstration of aberrant vessel as a cause of UPJ obstruction, although accuracy was low.