Radiation dose reduction using 100-kVp and a sinogram-affirmed iterative reconstruction algorithm in adolescent head CT: Impact on grey–white matter contrast and image noise

Objectives To retrospectively evaluate the image quality and radiation dose of 100-kVp scans with sinogram-affirmed iterative reconstruction (IR) for unenhanced head CT in adolescents. Methods Sixty-nine patients aged 12–17 years underwent head CT under 120- (n = 34) or 100-kVp (n = 35) protocols. The 120-kVp images were reconstructed with filtered back-projection (FBP), 100-kVp images with FBP (100-kVp-F) and sinogram-affirmed IR (100-kVp-S). We compared the effective dose (ED), grey–white matter (GM–WM) contrast, image noise, and contrast-to-noise ratio (CNR) between protocols in supratentorial (ST) and posterior fossa (PS). We also assessed GM–WM contrast, image noise, sharpness, artifacts, and overall image quality on a four-point scale. Results ED was 46% lower with 100- than 120-kVp ( p < 0.001). GM–WM contrast was higher, and image noise was lower, on 100-kVp-S than 120-kVp at ST ( p < 0.001). CNR of 100-kVp-S was higher than of 120-kVp ( p < 0.001). GM–WM contrast of 100-kVp-S was subjectively rated as better than of 120-kVp ( p < 0.001). There were no significant differences in the other criteria between 100-kVp-S and 120-kVp ( p = 0.072–0.966). Conclusions The 100-kVp with sinogram-affirmed IR facilitated dramatic radiation reduction and better GM–WM contrast without increasing image noise in adolescent head CT. Key points • 100 - kVp head CT provides 46 % radiation dose reduction compared with 120 - kVp . • 100 - kVp scanning improves subjective and objective GM – WM contrast . • Sinogram - affirmed IR decreases head CT image noise , especially in supratentorial region . • 100 - kVp protocol with sinogram - affirmed IR is suited for adolescent head CT .