Other clinical tests or procedures that monitor the presence of dopamine within the brain (β-CIT SPECT and IBZM SPECT) have shown similar findings. β-CIT serves as an indicator for presynaptic dopaminergic neurons, whereas IBZM is a tracer that shows an affinity for the postsynaptic neurons of the same type. Despite agreement with other imaging studies, these two SPECT methods suffer some scrutiny due to better accuracy in other imaging methods. However, β-CIT SPECT has proven to be helpful in distinguishing CBD from PSP and multiple system atrophy (MSA).