Initial experience with adaptive iterative dose reduction 3D to reduce radiation dose in computed tomographic urography.

OBJECTIVE: This study aimed to investigate the feasibility of low-dose computed tomographic (CT) urography with adaptive iterative dose reduction 3D (AIDR 3D). METHODS: Thirty patients underwent routine-dose CT scans with filtered back projection and low-dose CT scans with AIDR 3D in the excretory phase of CT urography. Visual evaluations were performed with respect to internal image noises, sharpness, streak artifacts, and diagnostic acceptability. Quantitative measures of the image noise and radiation dose were also obtained. All results were compared on the basis of body mass index (BMI). RESULTS: At visual evaluations, streak artifacts in the urinary bladder were statistically weaker on low-dose CT than on routine-dose CT in the axial and coronal images (P < 0.001 and P = 0.01). There were no statistical differences between routine-dose CT and low-dose CT for other evaluation items in all structures. Image noise was lower on low-dose CT than on routine-dose CT in all structures (P < 0.001). The overall average dose reduction was 45.0% in all patients. The average dose reduction for the patients with a BMI of less than 20, 20 to 25, greater than 25 kg/m was 43.0%, 44.0%, and 49.6%, respectively. CONCLUSION: Low-dose CT urography with AIDR 3D allows 45% reduction of radiation dose without degenerating of the image quality in the excretory phase independently to a BMI.