As far as I know chemical imbalance of the brain does not show up on c scans unless it is caused by tomors aneurysms and other physical ailments in which case its the tumors and aneurysms that show up not the chemical imbalance.. C scans are a type of x ray they can only detect physical problems not mental problems. Your doctor was probably ruling out tumors and so on first before diagnosising as schitophrenia. especially if this is a medical doctor not a psychiatrist or psychologist who would have used a test called a Comprehensive Psychological Evaluation to diagnose the schitophrenia.