To investigate the feasibility of reducing radiation dose in cerebral perfusion CT (CTP) while maintaining diagnostic accuracy by optimizing temporal resolution.

This retrospective cohort study included 117 stroke-suspected patients undergoing CTP at the First Affiliated Hospital of Army Medical University from January to September 2025. Three protocols were designed: Protocol 1 (full temporal resolution, 21-phase acquisition, baseline), Protocol 2 (every-other-phase sampling),Protocol 3 (peak-enhancement +1/-1 phase retention with every-other-phase sampling for remaining phases). Radiation reduction percentages relative to Protocol 1 were calculated. Regions of interest (ROI) were placed in ischemic core/penumbra to measure mean±SD of perfusion parameters: time to maximum of the residue function (Tmax), mean transit time（MTT), cerebral blood volume（CBV) and cerebral blood flow（CBF). Inter-protocol differences were assessed, and ischemic penumbra volume discrepancies were also analyzed.

Protocol 2 and 3 reduced radiation dose by 50.0% and 42.9% versus Protocol 1, respectively. For perfusion parameters: Tmax SD differed significantly across protocols [F(1.92,222.42)=11.17, P<0.001, partial η²=0.09]; post hoc tests showed significant mean differences between Protocol 1 vs 2 (P<0.016 7) and Protocol 1 vs 3 (P<0.016 7), but not Protocol 2 vs 3. MTT means showed no significant difference [F(1.88,218.11)=0.47, partial η²=0.004] , though SD differed significantly between Protocol 1 vs 2 and 1 vs 3 (P<0.016 7). CBV SD differed significantly [F(1.98,229.25)=22.97, P<0.001, partial η²=0.17] with no mean difference (Friedman test). CBF means showed no significant difference (Bonferroni-adjusted) but SD differed significantly between Protocol 1 vs 2 and 1 vs 3 (P<0.016 7). Ischemic penumbra volumes differed significantly across all protocols (P<0.016 7).

Temporal resolution optimization significantly reduces CTP radiation dose while minimally impacting core perfusion parameters (MTT, CBV, CBF means). CBF remained stable across reduced-dose protocols and may serve as a reliable diagnostic criterion for infarct core delineation.