Attenuation-Based Automatic Tube Potential Selection in Cerebral Computed Tomography Angiography: Effects on Radiation Exposure and Image Quality

Objective: To investigate the feasibility of using the attenuation-based automatic tube potential selection (ATPS) algorithm for cerebral computed tomography angiography (CTA) and to assess radiation dose, vascular attenuation, and image quality compared to a conventional fixed 120-kVp protocol. Materials and Methods: Among 36 volunteers for cerebral CTA, a total of 18 were scanned with fixed 120 kVp and 140 effective mAs using automatic tube current modulation. The other 18 were scanned with an ATPS algorithm. Radiation doses, attenuation, contrast-to-noise ratio (CNR) of the cerebral arteries, subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, venous contamination, image noise, and overall image quality were compared between the groups. Results: The volume CT dose index and effective dose of the ATPS group were lower than those of the fixed 120-kVp group. The ATPS group had significantly higher arterial attenuation and no significant difference in CNR, compared with the fixed 120- kVp. The ATPS group had higher subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, and overall image quality. Conclusion: The ATPS algorithm for the cerebral CTA reduced radiation dose by 43% while maintaining image quality and improved the attenuation of cerebral arteries by selecting lower tube potential.