Conventional and reduced radiation dose of 16-MDCT for detection of nephrolithiasis and ureterolithiasis.
OBJECTIVE
Our purpose was to prospectively compare the reader compatibility and acceptability of a range of reduced-dose 16-MDCT images with standard-dose 16-MDCT images for the detection of nephroureterolithiasis using a dose reduction simulation technique.


METHODS
The study was HIPAA compliant and institutional review board approved. Fifty consecutive patients with suspected nephrolithiasis were recruited to undergo conventional renal stone unenhanced 16-MDCT with at least 160 mA. Noise was then artificially introduced to simulate levels of 70, 100, and 130 mA. Three blinded independent readers interpreted the original and simulated-dose scans for the location and number of renal and ureteral calculi and secondary signs of obstruction using a 5-point confidence scale.


RESULTS
Reader acceptability of scans was inversely related to noise. There was no significant reduction in readers' confidence in detection or exclusion of renal collecting system calculi with simulated reduction of mA of 70, 100, and 130 compared with the standard-dose study. However, for ureteral calcifications, there was a decrease in confidence for the detection or exclusion of ureterolithiasis at an mA of 70 (35 mAs).


CONCLUSIONS
An mA as low as 70 (35 mAs) is acceptable for evaluation of nephrolithiasis. However, the evaluation of ureterolithiasis is compromised with an mA of 70.
Paulson
Erik K
EK
Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710, USA. pauls003@mc.duke.edu
Weaver
Carolyn
C
Ho
Lisa M
LM
Martin
Lucie
L
Li
Jianying
J
Darsie
James
J
Frush
Donald P
DP
D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053040:Nephrolithiasis / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D014057:Tomography, X-Ray Computed; D053039:Ureterolithiasis / Q000000981:diagnostic imaging*
D003287:Contrast Media