Cerebral Perfusion and Blood−Brain Barrier Changes After Cranioplasty: A Diffusion-Prepared Arterial Spin Labeling Study

Background and Purpose: Cranioplasty reconstruction after hemicraniectomy restores skull integrity and has been associated with neurological improvement, but the physiological mechanisms underlying recovery remain incompletely understood. This study investigated cerebral blood flow (CBF), arterial transit time (ATT), and blood–brain barrier (BBB) water exchange rate (Kw) as imaging metrics of hemodynamic recovery following cranioplasty. Methods: Fourteen patients (mean age: 33.4 ± 8.53 years; 2 females, 12 males) who previously underwent hemicraniectomy for traumatic brain injury, ruptured aneurysm, or hemorrhagic stroke were included. All participants underwent diffusion-prepared pseudo-continuous arterial spin labeling (DP-pCASL) Magnetic Resonance Imaging (MRI) at 3 Tesla before and after cranioplasty. Hemodynamic parameters were quantified globally and regionally, with particular focus on the middle cerebral artery perforator (MCA Perf) territory. Results: Post-surgical imaging revealed significant increases in CBF within the ipsilateral MCA Perf territory compared to pre-surgical values. BBB Kw asymmetry between MCA Perf territories also improved, indicating enhanced perfusion and BBB function in the impacted hemisphere. ATT changes were region-specific, with significant increases in asymmetry observed in the leptomeningeal anterior cerebral artery and posterior cerebral artery territories, but not in the MCA Perf region. Conclusions: These findings underscore the mechanobiological role of cranioplasty reconstruction in neurological recovery. Advanced hemodynamic imaging with DP-pCASL MRI provides quantitative insight into cerebral perfusion, BBB function, and regional perfusion timing. This approach may guide future research on post-cranioplasty recovery and inform personalized rehabilitation strategies.