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

To evaluate the radiation dose and image quality of cerebral CT angiography (CTA) at 70kVp with 30mL iodinated contrast agent.

One hundred patients were prospectively classified into two groups: Group A (n=50), 120kVp cerebral CTA with 60mL iodinated contrast agent reconstructed by filtered back projection (FBP) and Group B (n=50), 70kVp with 30mL 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.

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±0.0mSv) was lower than Group A (1.3±0.1 mSv) (p<0.001).

Cerebral CTA with iterative reconstruction at 70kVp and 30mL iodinated contrast agent is feasible, allowing for substantial dose reduction compared with conventional cerebral CTA protocol.