Comparative study of non-contrast-enhanced spirat CT scan to ultrasonography in the diagnosis of acute renal colic

ABSTRACT

To evaluate the sensitivity and specificity of noncontrast spiral CT scan in ureteric colic with comparative evaluation of ultrasonography. Prospective comparative study. This study was conducted at the Dept. of Radiology, Nishtar Medical College and Hospital, Multan from June, 2010 to June 2011. 62 patients with flank pain were examined with both ultrasonography and non contrast enhanced 16 slice spiral CT scan over a period of one year. Both techniques were used to determine the presence, size, and location of ureteric stone, and the presence or absence of secondary signs like ureteral and calyceal dilatation, stranding of perinephric, periureteric fat and soft tissue rim sign. 43 of the 62 patients were confirmed as having ureteric calculi based on stoned recovery or urological intervention. Ultrasound showed 93% sensitivity and 95% specificity in the diagnosis of ureterolithiasis. CT scan showed 91% sensitivity and 95% specificity respectively. hydronephrosis was seen in all patients that were positive for ureteric calculi. Most common site of calculus was distal ureter. Perinephric fluid was demonstrated in three patients. Perinephric stranding was seen in 26 cases, and periureteric stranding in three patients on CT scan. Pathology unrelated to urinary stone disease was demonstrated in six patients. Although both modalities were excellent for detecting ureteric stones, consideration of cost and radiation lead us to suggest that ultrasound be employed first and CT scan be reserved for when ultrasound is unavailable or non-diagnostic