What do my mri results mean; chronic microvas ischemic changes noted, frontal bone lesion & slightly abnormally shaped & low lying cerebellar tonsil.

Hard to say: urs best to discuss this with a neurology doctor, who can get full history. Picture by itself is just a picture-need medical hx and exam. So far it may look that there are changes- probably due to long history of smoking or other vascular disease .... As far as the shape of the brain parts and frontal lesion- it's impossible to tell without more info