Imaging of Angiogenesis in White Matter Hyperintensities

Abstract

Background White matter hyperintensities (WMHs) are areas of increased signal intensity on T2‐weighted magnetic resonance imaging (MRI). WMH penumbra may be a potential target for early intervention in WMHs. We explored the relationship between angiogenesis and WMH penumbra in patients with WMHs. Methods and Results Twenty‐one patients with confluent WMHs of Fazekas grade ≥2 were included. All the participants underwent 68Ga‐NOTA‐PRGD2 positron emission tomography/magnetic resonance imaging. WMH penumbra was analyzed with masks created for the WMH and 7 normal‐appearing white matter layers; each layer was dilated away from the WMH by 2 mm. Angiogenesis array and ELISA were used to detect the serum levels of angiogenic factors, inflammatory factors, HIF‐1 alpha, and S100B. Fourteen patients with increased 68Ga‐NOTA‐PRGD2 maximum standardized uptake (>0.17) were classified into group 2. Seven patients with maximum standardized uptake ≤0.17 were classified as group 1. WMH volume and serum levels of integrin αvβ3, vascular endothelial growth factor receptor 22, and interleukin‐1β tended to be higher in group 2 than in group 1. In group 2, 68Ga‐NOTA‐PRGD2 uptake was significantly increased at the border between the WMH and normal‐appearing white matter than in WMHs (P=0.004). The structure penumbra, defined by fractional anisotropy, was wider in group 2 (8 mm) than in group 1 (2 mm). The cerebral blood flow penumbra was 12 mm in both groups. Angiogenesis showed a correlation with reduced cerebral blood flow and microstructure integrity. Conclusions Our study provides evidence that angiogenesis occurs in the WMH penumbra. Further studies are warranted to verify the effect of angiogenesis on WMH growth.

Keywords

• angiogenesis
• cerebral blood flow
• PET/MRI
• white matter hyperintensities