What does this mean? Mild global brain parenchymal atrophy is noted. There is minimal ill defined hypodensity in the periventricular white matter at frontal lobes, suggestive of minimal small vessel ischemic disease. No hemorrhage or mass and no hydrocephalus is present. Grey matter differentiation is preserved. Bony skull is unremarkable. My dad, who has dementia, had a CT scan and these are the results.