A comparison between low dose and standard dose computed tomography scan in detection of urolithiasis

Abstract

Background: Computed tomography (CT) (standard and low-dose CT [LDCT] scan) has become the reference technique in medical imaging for urinary calculi, to diagnose, plan treatment, and explore differential diagnosis of renal colic. Objective: This study was done to compare the low-dose nonenhanced CT scan with standard dose CT scan in the detection of urolithiasis. Materials and Methods: Cross-sectional study conducted from 2017 to 2018 in Al-Hilla teaching general hospital on 60 patients undergone unenhanced (native) spectral detector CT (SDCT) and LDCT, the patients were scanned by Siemens CT system, 64 slice using automated tube current modulation, all CT scan were performed without oral or intravenous contrast. Results: This study showed that 93 stones detected by SDCT scan and 89 stones detected by LDCT 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). In 46.6% 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% of stones 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 to size of stones 11.9% of stones had size 20 mm. In standard CT scan, the current mean was 283.2 while in LDCT scan the mean was 126.1 mA, sensitivity is (93%) and specificity (100%) of LDCT in reference SDCT. Conclusion: LDCT scans provide effective methods of identifying and evaluating urinary tract stones, high diagnostic accuracy, sensitivity, and specificity are maintained despite significant radiation dose reduction compared to standard dose CT.