Samet GENEZ, Mustafa HIZAL, Ayşenur BUZ YAŞAR, Rüveyde Begüm YÜZOK, Hamza ÖZER, Yunus YILMAZSOY
Cerrahpaşa Medical Journal - 2026;50(1):1-6
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), were compared 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.
