Diagnostic Accuracy of Low and Ultra-Low Dose CT for Identification of Urinary Tract Stones: A Systematic Review.

BACKGROUND: Non-contrast computed tomography of the kidneys, ureters, and bladder (CT KUB) is the investigation of choice for renal colic; however, radiation exposure can be a concern.

AIMS: The study aimed to investigate the diagnostic accuracy of low dose (LD) and ultra-low dose (ULD) CT of the urinary tract for detection of urinary tract stones in patients with renal colic.

METHODS: A Cochrane style systematic review of the literature from 1995 to 2017 was carried out. Literature search and data extraction were conducted by 2 reviewers. Specificity and sensitivity values were calculated for LD (<3.5 mean radiation dose [mSv]) and ULD (<1.9 mSv) CT separately.

RESULTS: A total of 12 studies were included following screening. A total of 1,529 patients were included in the review (475 in the LD group and 1,054 in the ULD group). Using standard dose CT KUB as the reference standard, the sensitivity of LD CT KUB ranged from 90 to 98% and specificity from 88 to 100%. The sensitivity of ULD CT KUB ranged from 72 to 99% and the specificity ranged from 86 to 100%. The diagnostic accuracy for LD CT was 94.3% and for ULD CT was 95.5%.

CONCLUSIONS: LD and ULD CT KUB provide effective methods of identifying urinary tract stones. High diagnostic accuracy, sensitivity, and specificity are maintained despite significant radiation dose reduction in comparison to standard dose CT.