Comparative Study of Ultrasound and Computerized Tomography for Nephrolithiasis Detection

Nephrolithiasis is occurrence of renal calculi produced by an interference in balance between solubility and precipitation of salts in urinary tract and in the kidneys. CTU was exposed to be extremely sensitive and specific for ureteric calculi. Study aimed to determine the (i) sensitivity and specificity of ultrasound (USG) in the detection of urinary tract calculi, (ii) size of renal calculi detected on USG and comparing with CTU, and (iii) size of renal calculi not seen on USG but detected on computed tomography urogram (CTU). Material and Methods: A total of 150 patients' USG and CTU were compared for existence of calculi. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of USG were calculated with CTU as the gold standard. Results: From the 150 sets of data collected, 45 calculi were identified on both USG and CTU. The sensitivity and specificity of renal calculi finding on USG were 53% and 85% respectively. The mean size of the renal calculus revealed on USG was 6.8 mm 3.8 mm and the mean size of the renal calculus not imagined on USG but identified on CTU was 3.5 mm 2.7 mm. The sensitivity and specificity of ureteric calculi finding on USG were 12% and 97% respectively. The sensitivity and specificity of urinary bladder calculi detection on USG were 20% and 100% respectively.