Role of Ultrasound Versus Computed Tomography in Localization of Ureteric Calculi in Patients with Renal Colic: A Retrospective Study.

Abstract

Background:
Ureteric calculi are a common cause of acute renal colic. Accurate localisation of the stone guides clinical management decisions. Ultrasound (USG) and non-contrast computed tomography (NCCT) are the two principal imaging modalities in current practice; their relative merits for stone localisation remain debated.
Objectives:
To compare the detection rate and localisation accuracy of USG and NCCT for ureteric calculi in patients presenting with acute renal colic.
Methods:
A retrospective review was conducted on 50 patients who presented with acute renal colic and had ureteric calculi confirmed on NCCT at a tertiary care hospital over a two-year period (2022–2024). All patients underwent both USG and NCCT. Stone location, size, and associated findings were recorded for each modality. NCCT served as the reference standard.
Results:
The study comprised 36 males and 14 females (mean age 39.4 years; range 21–68 years). Lower ureteric and vesicoureteric junction stones were the most common location (44.0% on NCCT). NCCT detected all 50 stones (100%), while USG detected 39 (78.0%). USG detection rates varied by stone size: 55.6% for stones under 5 mm, 87.5% for 5–10 mm, and 100% for stones above 10 mm (p = 0.003). USG identified hydronephrosis in 38 patients (76.0%) versus 42 on NCCT (84.0%). Location concordance between the two modalities was 84.6% among USG-detected stones. The overall stone-free rate at four weeks was 86.0% (43 of 50 patients).
Conclusion:
NCCT is superior to USG for detecting and localising ureteric calculi across all stone sizes and locations. USG remains a useful first-line investigation for larger stones and for identifying significant hydronephrosis, and should be employed to limit radiation exposure, with NCCT reserved for equivocal cases or when precise localisation is required for intervention planning.