Abstract|Movement Disorders 2| Volume 357, SUPPLEMENT 1, e55, October 15, 2015

The clinical utility of [123i]-FP–CIT SPECT in tremor type versus non-tremor type clinically uncertain Parkinsonian syndrome

      Background: [123I]-FP–CIT SPECT has been approved to differentiate essential tremor from tremor due to Parkinsonian syndromes. Although off-label use is not uncommon, the utility of [123I]-FP–CIT-SPECT in non-tremor type Clinically Uncertain Parkinsonian Syndrome (CUPS) has not been well established.
      Objectives: To assess if the use of [123I]-FP–CIT-SPECT would lead to changes in clinical management and diagnosis in patients presenting with tremor type versus non-tremor type CUPS.
      Patients and methods: We retrospectively reviewed clinical records of all patients with [123I]-FP–CIT-SPECT obtained at our institution between January, 2012 and March, 2014. The study was approved by the local institutional review board.
      Results: Thirty-eight consecutive patients with [123I]-FP–CIT-SPECT images were analyzed. Prior to the [123I]-FP–CIT-SPECT scans, 27 were classified as CUPS, and 11 as a clinically certain Parkinsonian syndrome (CCPS) including Parkinson's disease (n = 8), progressive supranuclear palsy (n = 2) and multiple system atrophy (n = 1). Ten (91%) of the 11 CCPS patients and 15 (56%) of the 27 CUPS patients had abnormal [123I]-FP–CIT-SPECT indicating presynaptic dopaminergic deficiency (Χ2 = 4.34, p = 0.04). Of the 27 CUPS patients, 13 presented with a tremor syndrome (54% with abnormal scan), and the remaining 14 patients presented with a non-tremor syndrome (57% with abnormal scan) (Χ2 = 0.03; p = NS). A change of diagnosis or management followed in 85% of tremor type CUPS and in 93% in non-tremor type CUPS patients.
      Conclusions: This study suggests that [123I]-FP–CIT-SPECT may contribute to changes in clinical management and diagnosis in both tremor type and non-tremor type CUPS.