The role of ultrasound in initial evaluation of renal colic

Objective: The objective of this study is to support the use of ultrasound examination in the initial evaluation of renal colic. Methods: From January 1998 through April 1998, 21 patients referred for radiographic evaluation of possible renal colic were studied prospectively. All referrals came from either emergency clinic of Prince Hashim Ben-Al-Hussein Hospital or out patient clinic of the same hospital. All sonographic studies were performed with real-time sector scanner (Kretz, Compeson 410 3.5-MHz Probe). Our sonographic criterion for a positive examination consisted of visualization of urinary tract calculus and unilateral hydronephrosis with or without ureterectasis or both. Results: Of the 21 patients studied the presence of urinary calculi was proved in 18 cases. The absence of calculi was established in 3 cases either by negative intravenous urography (2 cases) or the by clinical and sonographic demonstration of epididymitis as the cause in one patient. In the 18 patients with proved urinary calculi, ultrasound correctly visualized the calculus in 15 cases (83%). Of the 15, 11 calculi were located at the ureterovesicular junction. 2 in the renal pelvis, one in the proximal third of the ureter, and one in the distal third. Using our sonographic criterion for positive examination mentioned in materials and methods, sensitivity was 95% (18/19). Specificity 95% (18/19). 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. In one patient the symptoms were found to be due to epididymitis, in the other case the symptoms remained unexplained following entirely normal intravenous urography. There were no false negatives in our series. Conclusion: The results of this study support the use of ultrasound as an alternative to intravenous urography for the initial evaluation of renal colic, in third world countries.