CT protocols used by researchers at Loma Linda University decreased radiation dose up to 95% when detecting distal ureteral calculi. The researchers used ultralow-dose CT as opposed to unenhanced multidetector CT.
A total of 85 calcium oxalate stones 3 to 7 mm long were prospectively placed in 14 human cadaveric distal ureters in 56 random configurations. The intact kidneys, ureters, and bladders were placed in the cadavers and CT was performed at 140, 100, 60, 30, 15, and 7.5 mA sec (J Urol 2009;182[6]:2762-2767).
Overall sensitivity and specificity were 98% and 83%. Imaging using 7.5 mA sec settings resulted in 97% sensitivity. Specificity was 84%.
