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

ObjectivesTo evaluate the radiation dose and image quality of cerebral CT angiography (CTA) at 70 kVp with 30 mL iodinated contrast agent.MethodsOne 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.ResultsThe 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). SNRICA, SNRMCA and CNRICA, CNRMCA 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).ConclusionCerebral 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.