a method of detecting parkinson &# 39 ; s disease through mri of substantial nigra pars compacta tissue . the method involves obtaining a gray matter suppressed mri signal from the snc tissue , obtaining a white matter suppressed mri signal of the snc tissue , and combining information from the gms and wms mri signals to produce resultant signals indicative of parkinson &# 39 ; s disease . a similar method can be used to detect progressive supranuclear palsy . a method of distinguishing between the two diseases involves obtaining at least two starting mri images of snc tissue using different mri parameters , and combining the starting images to compute resultant signals differentiating between the two forms of parkinsonism .