Investigations for recognizing urinary stone

Abstract

This study was done to identify the value of the commonly performed investigations available for identifying urinary stone disease, namely X-ray of the kidney, ureter and bladder (KUB) regions and ultrasound scan (USS) to recognize stones in patients suspected to have the disease. Two hundred patients who attended the stone clinic with symptoms suggestive of urinary stone disease and had either stone retrieved or have been followed up for minimum of 6 months were interviewed. The final opinion on stone disease was made after follow-up to assess the efficacy of the initial opinion based on the plain X-ray KUB or USS. The patients were classified as proved stone patients only after retrieval of stones. The efficacy of the initial screening investigation was assessed to calculate the specificity and sensitivity of the two modalities of investigation. Of the 200 patients studied, all had plain X-ray KUB. Only 166 patients had USS for recognizing stones in the urinary tract; 74 patients showed positive evidence of stones either by X-ray or USS. The findings of the two modalities of investigation are given below. Number of X-rays done, 200; number positive, 24; proved positive, 24 (stone retrieved); proved negative, 0; number negative, 176; proved positive, 32 (stone retrieved); proved negative, 144; number of USS done, 166; number positive, 120; proved positive, 50 (stone retrieved); proved negative, 70; number negative, 46; proved positive, 14 (stone retrieved); proved negative, 32. USS showed back presence effects in 62 patients. Of these, 12% showed stones in the ureter, whereas the rest did not show evidence of stones. Those selected as positive stones finally had either passed stones or had PCNL, URS, cystolithotripsy or open surgery or were put on high-dose chemotherapy. Forty-six patients who had no ROS in KUB and no stones in USS passed stones subsequently. It is concluded that the plain both X-ray KUB and USS should be performed in patients with suspected stone disease for identifying stone disease and also to exclude other pathology which may produce similar urinary symptoms.