Abstract

Background
Although the decrease in striatal dopamine transporter (DAT) density has been described in North American, European, and Asian Parkinson’s disease (PD) patients, studies on this issue are required in the rest of the world. This study examined the diagnostic utility of DAT imaging in Brazilian PD patients.
Material and Methods
Twenty PD patients (13 males, 7 females, median age: 62 years, median age at disease onset: 56 years, median disease duration: 5 years, and median UPDRS-III score: 29) and 9 age- and sex-matched healthy subjects underwent single-photon emission computerized tomography (SPECT) using 99mTc-TRODAT-1.
Results
PD patients showed a significant decrease in the striatum, caudate nucleus, and putamen DAT densities compared with data from healthy subjects. Striatal 99mTc-TRODAT-1 bindings had the highest diagnostic accuracy compared to those estimates from caudate nucleus and putamen. For the diagnosis of PD, a striatal 99mTc-TRODAT-1 binding cut-off value of 0.90 was associated with a sensitivity of 100% and a specificity of 89%. There was no significant difference between striatal 99mTc-TRODAT-1 binding values provided by different readers, contrary to 99mTc-TRODAT-1 binding estimates in the caudate nucleus.
Conclusions
Striatal DAT imaging using 99mTc-TRODAT-1 can be considered a marker for differentiating PD patients from healthy individuals, with a good interobserver reproducibility.

Keywords: Corpus Striatum - metabolism, Brazil, Dopamine Plasma Membrane Transport Proteins - diagnostic use, Organotechnetium Compounds - diagnostic use, Parkinson Disease - diagnosis, Reproducibility of Results, Tomography, Emission-Computed, Single-Photon - methods, Tropanes - diagnostic use