The role of ultrasound in initial evaluation of renal colic.

The objective of this study is to evaluate the use of ultrasound in the initial evaluation of renal colic. We studied prospectively 21 patients referred for radiographic evaluation for renal colic from January 1998 through April 1998. All sonographic studies were performed with real-time sector scanner (Kertz, Compeson 410 using 3.5 MHz Probe). Our sonographic criteria for a positive examination consisted of the visualization of urinary tract calculus and/or unilateral hydronephrosis with or without ureterectasis. The presence of urinary calculi was proven in 18 out of 21 patients (85%). The absence of calculi was established in three cases either by negative I.V.U. (2 cases) or by the clinical and sonographic demonstration of epididymitis as the cause in one patient. In the 18 patients with proven urinary calculi, ultrasound correctly identified the diagnosis in 15 cases (83%). Of those 15 visualized calculi, 11 were located at the ureterovesicular junction, two in the renal pelvis, one in the proximal third of the ureter, and one in the distal third. The sensitivity of ultasonography to detect renal calculi was 83% and the specificity, 100%. The one false positive examination with unilateral hydronephrosis proved to be due to a retroperitoneal liposarcoma. There were two cases in which the urinary tract ultrasound examination was negative. We conclude that ultrasound has a high diagnostic value when used as the first line investigation for the initial evaluation of renal colic.