Role of dopamine transporter imaging in investigation of parkinsonian syndromes in routine clinical practice.

We discuss the potential role of dopamine transporter (DAT) imaging by single photon emission computed tomography (SPECT) as a biological marker for differentiating among parkinsonian disorders in routine clinical practice, and the implication for disease progression assessment is considered. Although clinical criteria enable accurate and reliable diagnosis of fully developed Parkinson's disease, there are several areas of diagnostic uncertainty relating to atypical parkinsonian disorders, isolated tremor symptoms not fulfilling essential tremor criteria, as well as drug-induced and psychogenetic parkinsonism. DAT-SPECT facilitates differential diagnosis of the different parkinsonian syndromes that cannot be reliably separated on clinical grounds and it can thus provide valuable diagnostic information in early disease.