Dose optimization in contrast-enhanced CT brain imaging using low tube voltage and reduced iodine concentration: a comparative study

Contrast Enhanced Computed Tomography (CECT) of the brain is frequently used for the evaluation of intracranial pathology; however, repeated examinations may increase cumulative radiation exposure and iodinated contrast load. This study evaluated whether a combined low tube voltage and reduced iodine concentration protocol could reduce radiation dose while maintaining diagnostic image quality in adult CECT brain imaging. In this single-centre comparative study, 180 adult patients undergoing CECT brain imaging were allocated to Group A ( n = 90), scanned using Iodixanol 320 mgI/mL at 120 kVp, or Group B ( n = 90), scanned using Iodixanol 270 mgI/mL at 100 kVp. Radiation exposure was assessed using volume CT dose index (CTDIvol), dose length product (DLP), and estimated effective dose (ED). Two radiologists independently evaluated image sharpness, artifacts, and overall image quality using Likert-based qualitative scales. Interobserver agreement was assessed using Cohen’s kappa statistic. Group B demonstrated significantly lower radiation exposure than Group A. Mean CTDIvol decreased from 49.9 ± 16.9 mGy to 31.2 ± 9.7 mGy ( p < 0.0001), while mean DLP decreased from 1187.15 ± 588.2 mGy·cm to 1027.35 ± 119.35 mGy·cm ( p = 0.01). The estimated effective dose was also significantly lower in Group B than in Group A (2.4 ± 1.2 mSv vs. 2.1 ± 0.2 mSv; p = 0.02). Diagnostic image quality was preserved in both groups. More than 87% of examinations were rated as having excellent sharpness, and 88.9–94.4% were rated as having excellent overall image quality. All examinations were considered artifact-free. Interobserver agreement was substantial to almost perfect for sharpness (κ = 0.88–0.89) and overall image quality (κ = 0.73–0.82). A CECT brain protocol using 100 kVp and Iodixanol 270 mgI/mL significantly reduced CTDIvol, DLP, and effective dose while preserving diagnostic image quality. This low-kVp, reduced-iodine protocol may provide a practical radiation- and contrast-efficient alternative to conventional 120-kVp brain CECT protocols.