COMPARATIVE DIAGNOSTIC ACCURACY OF LOW-DOSE CT KUB AND CONVENTIONAL CT IN DETECTING RENAL AND URETERIC CALCULI

Pari Gul

COMPARATIVE DIAGNOSTIC ACCURACY OF LOW-DOSE CT KUB AND CONVENTIONAL CT IN DETECTING RENAL AND URETERIC CALCULI

Pari Gul

Abstract

Introduction: Urolithiasis is a common condition with a recurrence rate of 50–70% over 10 years. Given the likelihood of repeated imaging, minimizing radiation exposure is a crucial consideration. Non-contrast computed tomography (CT) is widely recommended as the first-line imaging modality for suspected renal colic due to its high sensitivity and specificity. This study aimed to evaluate the diagnostic accuracy of low-dose CT KUB compared to conventional CT in detecting renal and ureteric calculi.

Objectives: To determine the diagnostic accuracy of low-dose CT KUB, using conventional CT as the gold standard, in detecting renal and ureteric calculi.

Study Design: Cross-sectional study.

Setting: Department of Radiology, Bolan Medical Complex Hospital, Quetta.

Study Duration: November 25, 2023 – May 24, 2024.

Materials & Methods: A total of 168 patients (both male and female, aged 15–60 years) with a history of urinary stones were included. Pregnant females and patients who had undergone extracorporeal shockwave lithotripsy (ESWL) were excluded. All enrolled patients underwent both low-dose CT KUB (<3.5 mSv) and conventional CT. A single consultant radiologist interpreted all CT scans for the presence or absence of renal and ureteric calculi.

Results: Low-dose CT KUB detected renal and ureteric calculi in 83 patients. Conventional CT confirmed 74 cases as true positive, while 9 were false positive. Among low-dose CT KUB-negative cases, 80 were true negatives, and 5 were false negatives. The calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy of low-dose CT KUB were 93.67%, 89.89%, 89.16%, 94.12%, and 91.67%, respectively, compared to conventional CT.

Conclusion: Low-dose CT KUB demonstrates high diagnostic accuracy for detecting renal and ureteric calculi, making it a valuable imaging modality in clinical practice. Its use can help minimize radiation exposure while maintaining reliable diagnostic performance.

Keywords: renal ureteric calculi, low-dose CT, sensitivity, specificity, diagnostic accuracy.

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