Nucl Med Mol Imaging.  2014 Jun;48(2):106-113.

Differential Diagnosis of Patients with Inconclusive Parkinsonian Features Using [18F]FP-CIT PET/CT

• Park E
• Hwang YM
• Lee CN
• Kim S
• Oh SY
• Kim YC
• Choe JG
• Park KW

Abstract

PURPOSE
It is often difficult to differentiate parkinsonism, especially when patients show uncertain parkinsonian features. We investigated the usefulness of dopamine transporter (DAT) imaging for the differential diagnosis of inconclusive parkinsonism using [18F]FP-CIT PET.
METHODS
Twenty-four patients with inconclusive parkinsonian features at initial clinical evaluation and nine healthy controls were studied. Patients consisted of three subgroups: nine patients whose diagnoses were unclear concerning whether they had idiopathic Parkinson's disease or drug-induced parkinsonism ('PD/DIP'), nine patients who fulfilled neither the diagnostic criteria of PD nor of essential tremor ('PD/ET'), and six patients who were alleged to have either PD or atypical parkinsonian syndrome ('PD/APS'). Brain PET images were obtained 120 min after injection of 185 MBq [18F]FP-CIT. Imaging results were quantified and compared with follow-up clinical diagnoses.
RESULTS
Overall, 11 of 24 patients demonstrated abnormally decreased DAT availability on the PET scans, whereas 13 were normal. PET results could diagnose PD/DIP and PD/ET patients as having PD in six patients, DIP in seven, and ET in five; however, the diagnoses of all six PD/APS patients remained inconclusive. Among 15 patients who obtained a final follow-up diagnosis, the image-based diagnosis was congruent with the follow-up diagnosis in 11 patients. Four unsolved cases had normal DAT availability, but clinically progressed to PD during the follow-up period.
CONCLUSION
[18F]FP-CIT PET imaging is useful in the differential diagnosis of patients with inconclusive parkinsonian features, except in patients who show atypical features or who eventually progress to PD.

Keyword

Parkinsonism; Inconclusive parkinsonian features; Dopamine transporter; [18F]FP-CIT; Positron emission tomography

MeSH Terms

Brain
Diagnosis
Diagnosis, Differential*
Dopamine Plasma Membrane Transport Proteins
Essential Tremor
Follow-Up Studies
Humans
Parkinson Disease
Parkinsonian Disorders
Positron-Emission Tomography
Positron-Emission Tomography and Computed Tomography*
Dopamine Plasma Membrane Transport Proteins