Clinical utility of dopamine transporter single photon emission CT (DaT-SPECT) with (123I) ioflupane in diagnosis of parkinsonian syndromes

Abstract

The diagnosis of movement disorders including Parkinson's disease (PD) and essential tremor is determined through clinical assessment. The difficulty with diagnosis of early PD has been highlighted in several recent clinical trials. Studies have suggested relatively high clinical diagnostic error rates for PD and essential tremor. This review was undertaken to clarify the utility of DaT-SPECT imaging with ((123)I)ioflupane (DaTSCAN or DaTscan or ((123)I)FP-CIT) in assisting practitioners in their clinical decision making by visualising the dopamine transporter in parkinsonian cases. In some patients with suspected parkinsonian syndromes, SPECT imaging with ((123)I)ioflupane is useful to assist in the diagnosis and to help guide prognosis and treatment decisions, including avoiding medications that are unlikely to provide benefit. Clinicians ordering ((123)I)ioflupane SPECT should be aware of its limitations and pitfalls and should order scans when there is diagnostic uncertainty or when the scan will be helpful in clinical decision making.

Keywords: Movement Disorders; Parkinson's Disease; Tremor.

Figure 1

(A) (¹²³I)Ioflupane selectively binds presynaptically to the DaT receptors within the striatum of the brain. Loss of DaT receptors is indicative of PS. (B): (¹²³I)Ioflupane is used in the clinical differentiation of PS from ET—where signs and symptoms can overlap in early onset of disease. (C) Visual detection of DaT distribution in vivo. Grade 1: asymmetrical loss of putaminal tail—‘comma with full stop’ Grade 2: bilateral loss of putaminal tails—‘two full stops’ Grade 3: Partial to complete loss of caudate and putaminal signal—‘disappearing full stops’. Reference: FDA prescribing information for DaTscan Website. Available at http://www.accessdata.fda.gov/drugsatfda_docs/nda/2011/022454sOrig1s000Lbl.pdf. (D) Diagnostic decision tree for patients with tremor and parkinsonism UKPDBBC, UK Parkinson's Disease Brain Bank Criteria; Dx, diagnosis; Rx, treatment.

Figure 1

(A) (¹²³I)Ioflupane selectively binds presynaptically to the DaT receptors within the striatum of the brain. Loss of DaT receptors is indicative of PS. (B): (¹²³I)Ioflupane is used in the clinical differentiation of PS from ET—where signs and symptoms can overlap in early onset of disease. (C) Visual detection of DaT distribution in vivo. Grade 1: asymmetrical loss of putaminal tail—‘comma with full stop’ Grade 2: bilateral loss of putaminal tails—‘two full stops’ Grade 3: Partial to complete loss of caudate and putaminal signal—‘disappearing full stops’. Reference: FDA prescribing information for DaTscan Website. Available at http://www.accessdata.fda.gov/drugsatfda_docs/nda/2011/022454sOrig1s000Lbl.pdf. (D) Diagnostic decision tree for patients with tremor and parkinsonism UKPDBBC, UK Parkinson's Disease Brain Bank Criteria; Dx, diagnosis; Rx, treatment.