Cerebral CT angiography with iterative reconstruction at 70 kVp and 30 mL iodinated contrast agent: Initial experience

Objectives: To evaluate the radiation dose and image quality of cerebral CT angiography (CTA) at 70 kVp with 30 mL iodinated contrast agent. Methods: One hundred patients were prospectively classified into two groups: Group A (n = 50), 120 kVp cerebral CTA with 60 mL iodinated contrast agent reconstructed by filtered back projection (FBP) and Group B (n = 50), 70 kVp with 30 mL iodinated contrast agent reconstructed by sinogram-affirmed iterative reconstruction (SAFIRE). CT values, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured. Subjective image quality was evaluated. Effective dose (ED) was calculated. Results: The mean CT values of the ICA and MCA of Group B were higher than those of Group A (all P < 0.001). The mean noise of Group A was lower than that of Group B (P < 0.001). SNR_ICA, SNR_MCA and CNR_ICA, CNR_MCA of Group A were higher than Group B (all P < 0.001). There was no difference in vessel sharpness, noise, and overall quality between the two groups (all P > 0.05). ED of Group B (0.2 ± 0.0 mSv) was lower than Group A (1.3 ± 0.1 mSv) (p < 0.001). Conclusion: Cerebral CTA with iterative reconstruction at 70 kVp and 30 mL iodinated contrast agent is feasible, allowing for substantial dose reduction compared with conventional cerebral CTA protocol.