Evaluation of Low-Dose Computed Tomography Protocols for Follow-Up Imaging in Intracranial Hemorrhage

Abstract

Objective: To evaluate and compare 2 low-dose non-contrast head computed tomography (CT) protocols for follow-up imaging of intracranial hemorrhage (ICH), focusing on radiation dose reduction and subjective image quality while maintaining diagnostic adequacy.

Methods: This single-center, retrospective, non-randomized study included 58 patients (May 2022–February 2023) who underwent follow-up CT for previously diagnosed ICH. Three protocols were analyzed: standard-dose (SD, 120 kVp, automatic tube current modulation), low-dose 1 (LD1, 80 kVp/160 mAs), and low-dose 2 (LD2, 80 kVp/320 mAs). All scans were reconstructed with the Adaptive Statistical Iterative Reconstruction–V algorithm (60% for SD, 80% for LD protocols). Subjective image quality was rated on a five-point Likert scale assessing overall visual impression, cerebrospinal fluid visibility, gray–white matter differentiation, hematoma conspicuity, ventricular delineation, edema visualization, and basal cisterns. Radiation dose parameters,including computed tomography dose index volume (CTDI_vol) and dose–length product (DLP), werecompared among groups using the Kruskal–Wallis test with post-hoc Dunn–Bonferroni correction.

Results: LD2 achieved significantly higher image quality scores than LD1 for most parameters (overall score 32.3 vs. 25.6, P < .001, r = 0.84). No significant difference was found between LD1 and LD2 regarding hemorrhage conspicuity (P = .133). Median DLP and CTDI(vol) values showed a stepwise increase from LD1 to SD (108 vs. 407 vs. 1136 mGy.cm and 4.8 vs. 20.4 vs. 50.9 mGy; P < .001). Both low-dose protocols achieved significant radiation reduction, with LD1 providing nearly 90% dose reduction compared with SD.

Conclusion: Both low-dose protocols preserved diagnostic adequacy for ICH follow-up while markedly reducing radiation exposure. The 80 kVp/160 mAs protocol offers an optimal balance between diagnostic acceptability and dose efficiency, making it suitable for routine follow-up CT of ICH.

Cite this article as: Genez S, Hızal M, Yaşar AB, Özer H, Yılmazsoy Y. Evaluation of low-dose computed tomography protocols for follow-up imaging in intracranial hemorrhage. Cerrahpaşa Med J. 2026, 50, 0084, doi:10.5152/cjm.2026.25084.