A Comparative Study on Diagnostic Accuracy of Ultrasound and CT in Nephrolithiasis

Dr. Swetha N, Dr. Chetan, Dr. Prashant G Patil, Dr. Ashok Kumar

Abstract: Introduction: Nephrolithiasis, commonly known as kidney stone disease, is a condition characterized by the formation of renal calculi due to an imbalance between the solubility and precipitation of salts in the urinary tract and kidneys. For diagnosis and treatment to be successful, renal and ureteric calculi must be accurately detected. Even though computed tomography urography (CTU) is thought to be very sensitive and specific, ultrasonography (USG) is still a popular non - invasive, radiation - free option. By analyzing USG's sensitivity and specificity in identifying urinary calculi, this study seeks to evaluate the diagnostic performance of the procedure. Material and Methods: A prospective study was performed on 120 patients with suspected nephrolithiasis, where each patient underwent both USG and CTU, with CTU serving as the gold standard. The diagnostic performance of USG, including sensitivity, specificity, and accuracy, was evaluated by comparing it to CTU findings in detecting renal calculi based on size and location. Results: USG demonstrated a sensitivity of 58% and specificity of 88% for renal calculi. For ureteric and bladder calculi, sensitivity was 25% and 55%, respectively. The mean size of calculi missed by USG was 3.2 mm ? 1.9 mm. Smaller stones (?5 mm) had a detection rate of 34%, while larger stones (5.1?10 mm) were detected 52% of the time. In contrast, computed tomography urography (CTU) demonstrated perfect sensitivity, specificity, and accuracy at 100%. Conclusion: Although CTU is more accurate, USG provides a reliable level of specificity for initial screening, especially for renal calculi. The effectiveness of USG in detecting stones varies depending on their size and location.

Keywords: Nephrolithiasis, Ultrasound, CT Urogram, Sensitivity, diagnostic accuracy