Achieving lower radiation dose of cerebral computed tomography angiography: The role of high-concentration contrast...

To investigate whether high-concentration iodine contrast medium (HICM) combined with low-dose radiation scanning protocols can further reduce the radiation dose of cerebral computed tomography angiography (CTA) scans without compromising image quality.

The prospective study included 150 eligible patients who underwent cranial CTA examinations. The patients were randomly divided into three groups (A, B, and C). All patients received a total iodine dose of 21.6 g and underwent scanning at tube voltage of 80 kV. Each group included 50 patients. Different protocols were applied as below. Group A: Iomeprol 400, iodine delivery rate (IDR) 2.0 g/s, tube current-time product (TCTP) 90 mAs; Group B: Iopromide 370, IDR 1.48 g/s, TCTP 164 mAs; Group C: Iopromide 370, IDR 2.0 g/s, TCTP 90 mAs. Radiation doses (Computer Tomography Dose Index Volume, Dose-Length Product, Effective Dose) were recorded, and CT attenuation values, image noise, Signal-to-Noise Ratio (SNR), and Contrast-to-Noise Ratio (CNR) were measured.

There were no statistically significant differences in the SNR and CNR of intracranial vessels among groups A, B, and C. Group A and C showed higher CT attenuation values and image noise, but lower radiation dose (reduced by 46.53% and 45.62% compared with Group B). The injection flow rate was lower in Group A.

A higher IDR is effective in reducing radiation dose. Moreover, higher iodine concentration (iomeprol 400) enables a lower injection flow rate to achieve a target IDR. A 46% reduction in radiation dose can be achieved using iomeprol 400 combined with a low-dose protocol, without compromising image quality, at an optimized injection flow rate.