A Comparison between Low Dose and Standard Dose Computed Tomography Scan in Detection of Urolithiasis


Background: Computed tomography (CT) (standard and low‑dose CT [LDCT] scan) has become the reference technique in medical imagingfor urinary calculi, to diagnose, plan treatment, and explore differential diagnosis of renal colic. Objective: This study was done to comparethe low‑dose nonenhanced CT scan with standard dose CT scan in the detection of urolithiasis. Materials and Methods: Cross‑sectionalstudy conducted from 2017 to 2018 in Al‑Hilla teaching general hospital on 60 patients undergone unenhanced (native) spectral detectorCT (SDCT) and LDCT, the patients were scanned by Siemens CT system, 64 slice using automated tube current modulation, all CT scan wereperformed without oral or intravenous contrast. Results: This study showed that 93 stones detected by SDCT scan and 89 stones detected byLDCT scan, mean age of patients 44.2 ± 7.3 and mean of body mass index 26.3 ± 3.1, male constitute 56.6% (34) and female 43.4% (26). In46.6% of patients had stone in the left side and 53.4% show stone in right side, most of patients presented solitary stone which appear 73.4%,11.6% of patients had double stone, 5% had triple stone, 6.6% had four stones, and 3.45% had 5 or more stone at investigation, 10.8% ofstones lie in ureter, 7.6% of stones in renal pelvis, 13.9% in upper calyx, 28% in lower calyx, and 39.7% lie in middle calyx, according tosize of stones 11.9% of stones had size <3 mm, 35.4% of stones range 3–5 mm, 34.5% size range 6–10 mm, 12.9% 11–15 mm in size, 3.25 ofstones had size range 16–20 mm and only 2.1% of stone had size >20 mm. In standard CT scan, the current mean was 283.2 while in LDCTscan the mean was 126.1 mA, sensitivity is (93%) and specificity (100%) of LDCT in reference SDCT. Conclusion: LDCT scans provideeffective methods of identifying and evaluating urinary tract stones, high diagnostic accuracy, sensitivity, and specificity are maintained despitesignificant radiation dose reduction compared to standard dose CT.