Muhammad Zafar Rafique, Muhammad Uzair Usman, Tanveer Ul Haq, Kashif Ashraf, Waseem Ahmed Memon.
Unenhanced helical CT Scan for Ureterolithiasis.
J Coll Physicians Surg Pak Jan ;14(8):508.

The study was carried out from November 2002 to January 2004 and included patients who presented with flank pain at the Aga Khan University Hospital. One hundred and twenty patients were excluded from the study that were less than 15 years of age, pregnant or had history of trauma and infection. A total of 80 out of these 200 patients were included in this study that had a CT diagnosis of ureteric calculus after a UEHCT. In all those 80 patients with diagnosis of ureteric calculus on CT scan was confirmed later on either IVU, stone passage in the urine, ESWL (extracorporeal shock wave lithotripsy) or on the ureteroscopic removal of calculus. The images were interpreted for site, size and location of ureteric calculus, hydronephrosis, hydroureter, perinephric stranding, periureteral stranding, nephromegaly and incidental findings. The age range was 15-69 years, with a mean age of 37.5 years. Out of 80 patients, 32 (40%) patients presented with right sided flank pain and 48 (60%) of the patients had left sided flank pain. In 12 (15 %) patients, calculi were present in the proximal ureter, in 24 (30%) in the mid ureter and in 44 (55%) in distal ureter. Most of the stones were between 3-5 mm size range (47%); 20% stones were less than 3 mm in size and 32.5 % of stones were more than 5 mm in size. Most common secondary sign was perinephric stranding seen in 48 patients (60%). The second most common secondary sign was periureteral stranding seen in 44 (55%) patients. In 30 of the patients (37.5%) hydronephrosis was observed. In 18 (22.5%) hydroureter was present. Nephromegaly was observed in 2.3 % of the patients. In 2 of 120 patients in which CT was negative, ureteric calculus was present on IVU which was carried out 3 days after UEHCT. In 2 of 120 patients in which CT was negative for ureteric calculus, ureteric calculus was present on IVU which was carried out 3 days after UEHCT. The sensitivity, specificity, positive and negative predictive values of unenhanced helical CT scan for detection of ureteric calculi was 97.5%, 98.3%, 97.5% and 98.3% respectively.

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