BACKGROUND: Flat-detector computed tomography (FDCT) is increasingly used for peri-interventional cerebral imaging but is associated with a relatively high radiation exposure. Copper (Cu) filtration may reduce radiation dose. However, its impact on cerebral image quality and intracranial hemorrhage detection remains unclear. METHODS: In this retrospective single-center study, 31 patients undergoing neurointerventional procedures with intraindividual FDCT acquisitions with and without Cu filtration were analyzed. Quantitative image quality was assessed using contrast-to-noise ratio (CNR). Qualitative image analysis and intracranial hemorrhage detection were independently evaluated by two readers blinded to Cu filtration status using five-point scales. RESULTS: Cu filtration resulted in a significant radiation dose reduction of 25.9% for both entrance skin dose (145.19±13.18 mGy vs 195.89±18.05 mGy) and dose-area product (41.52±3.77 Gy·cm² vs 56.01±5.16 Gy·cm²), respectively (P<0.001). No differences in CNR were observed for unfiltered vs Cu-filtered FDCT (basal ganglia: 4.73±2.04 vs 4.37±1.99, P=0.419). Qualitative image ratings were similar between techniques (supratentorial cortex: 2.27±0.66 vs 2.08±0.75, P=0.089), with very good inter-reader agreement (κ=0.86; 95% CI: 0.80 to 0.91). All intracranial hemorrhages were correctly identified by both techniques. Correct exclusion of intracranial hemorrhage was 15/16 with Cu filtration and 14/16 without Cu filtration, without statistically significant difference. Differences were limited to hemorrhage mimics (n=2) and minor variations in diagnostic confidence without affecting binary classification. CONCLUSION: Cu filtration in cerebral FDCT enables substantial radiation dose reduction while preserving image quality and intracranial hemorrhage detection, supporting its clinical implementation as a practical dose optimization strategy for peri-interventional imaging.