Background and Purpose To investigate the effect of chronic hyperglycemia on cerebral microvascular remodeling using perfusion computed tomography. Methods We retrospectively identified 26 patients from our registry of 2453 patients who underwent a perfusion computed tomographic study and had their hemoglobin A(1c) (HbA(1c)) measured. These 26 patients were divided into 2 groups: those with HbA(1c)>6.5% (n=15) and those with HbA(1c)6.5% (n=11). Perfusion computed tomographic studies were processed using a delay-corrected, deconvolution-based software. Perfusion computed tomographic values were compared between the 2 patient groups, including mean transit time, which relates to the cerebral capillary architecture and length. Results Mean transit time values in the nonischemic cerebral hemisphere were significantly longer in the patients with HbA(1c)>6.5% (P=0.033), especially in the white matter (P=0.005). Significant correlation (R=0.469; P=0.016) between mean transit time and HbA(1c) level was observed. Conclusions Our results from a small sample suggest that chronic hyperglycemia may be associated with cerebral microvascular remodeling in humans. Additional prospective studies with larger sample size are required to confirm this observation.