An MRI brain scan is not used to determine the diagnosis of parkinsonism. The diagnosis of parkinsonism is set in the consulting room, based on a clinical review by a neurologist (listening to the patient’s observations, and a thorough neurological examination). If there are doubts about the type of parkinsonism (for example, is it Parkinson's disease, or just a form of atypical parkinsonism?), an MRI brain scan will be made. Such a scan does not reveal any abnormalities in people with real Parkinson's disease, but may show specific abnormalities in people with atypical parkinsonism (especially if the disease exists for a long time). Thus, the scan is not used to detect parkinsonism, but just to exclude or indicate other conditions. In addition, the MRI scan does not provide an absolute diagnosis for any of these conditions - only brain examinations after death gives absolute certainty.