Evaluation of diagnostic value of fused 99m Tc-TRODAT-1 SPECT on MRI in differentiation of parkinsonism

Abstract

Parkinson’s disease, parkinsonian syndromes and essential tremor are a group of movement disorders with a similar clinical presentation. Therefore differentiating these diseases is difficult specially in the first stages.The routine anatomical imaging like computerized tomography and magnetic resonance imaging, doesn’t suggest specific findings for the differentiation of these movement disorders.The use of nuclear medicine imaging with 99m Tc-TRODAT-1 that is absorbed by the presynaptic neurons of the basal ganglia, have shown great promise in differentiating parkinson’s disease from essential tremor. But unfortunately it has some limitations in imaging smaller organs like the basal ganglia.Therefore, in this study we co-registered both anatomical MRI and functional SPECT images hopefully to better differentiate parkinsonian syndromes. Material and methods: This cross-sectional study with diagnostic test evaluation, was performed with 40 patients with the clinical presentation of parkinsonism, which were referred from neurology clinics. To determine sample size in regard to the limitations of the study, all patients that met the inclusion criteria were enrolled by sensus. Four hours after administration of 25mc 99m Tc-TRODAT-1, images were taken with gamma camera SPECT at Imam Reza nuclear medicine imaging center or special clinic of Tabriz university (Tabriz Gamma Scan center). SPECT images were then co-registered on MRI images and the uptake values were calculated in basal ganglia semi-quantitatively and qualitatively. Results:In the current study, in comparison between primary parkinsonism (parkinson’s disease and progressive supranuclear palsy) with essential tremor, the uptake values were significantly higher in the essential tremor group (p<0.05), and these findings were similar in SPECT and MRI/SPECT. But the findings in differentiation of primary parkinsonism (parkinson’s disease from supranuclear palsy) were not significant (p>0.05). In evaluation of the uptake pattern, the lateralization of decreased uptake was only seen in parkinson’s disease patients; and in parkinsonian syndrome (progressive supranuclear palsy) , the reduced uptake was bilateral in all patients. In this study the putamen nucleus in parkinson’s disease was more frequently involved than caudate nucleus, and in progressive supranuclear palsy caudate nucleus was more frequently involved than putamen nucleus.