Diagnostic Evaluation of 99mTc-TRODAT-1 SPECT in Parkinsonism

Zahra Babaei Aghdam,Amin Arasteh,Safa Najmi Tabrizi,Babak Mahmoudian,Mohammad Khalafi,Morteza Ghojazadeh

doi:10.34172/jrcm.2021.036

Abstract

Background Parkinsonism as a group of movement disorders, exhibit similar clinical presentation. Therefore, clinically differentiating these diseases is difficult. We investigated the diagnostic value of 99m Tc-TRODAT-1 SPECT in this setting. Due to the fact that this modality has some limitations in imaging small organs like the sub-regions of basal ganglia, we also evaluated the use of anatomical MR imaging along with functional SPECT imaging in parkinsonism. Methods This follow-up diagnostic test evaluation study was performed with 40 patients with the clinical presentation of parkinsonism, and 10 healthy subjects as controls. After administration of the radiopharmaceutical, SPECT images were acquired, then co-registered on MRI. Uptake values were evaluated in basal ganglia semi-quantitatively. Results In this study, 99mTc-TRODAT-1 SPECT was able to differentiate essential tremor and healthy subjects from progressive supranuclear palsy (PSP) and Parkinson’s disease (PD) with a sensitivity of 76.47% and specificity of 100% at a cut-off of 0.53; however, findings were not significant in differentiation of PD from PSP (p ˃0.05), and the results were similar in SPECT and co-registered MRI/SPECT images. In evaluation of the uptake pattern in basal ganglia, the lateralization of decreased uptake was only seen in PD; and in PSP, the dysfunction was bilateral in all patients. Conclusion 99mTc-TRODAT-1 SPECT is sensitive and specific in diagnosing basal ganglia dysfunction; however, 99mTc-TRODAT-1 SPECT alone or co-registration on MRI are not adequate in differentiation of the etiologies of basal ganglia dysfunction.

Highlights

Parkinsonism as a group of movement disorders, exhibits similar clinical presentation
We investigated the diagnostic value of 99m Tc-TRODAT-1 SPECT in this setting
Due to the fact that this modality has some limitations in imaging small organs like the subregions of basal ganglia, we evaluated the use of anatomical magnetic resonance imaging (MRI) along with functional SPECT imaging in parkinsonism

Summary

Introduction

Parkinsonism as a group of movement disorders, exhibits similar clinical presentation. Autosomal dominant mutations in a gene for a-synuclein and toxins such as MPTP (1-methyl-4-phenyl-1,2,3,6tetrahydropyridine) are responsible for structural and functional processes, respectively.[2] The overall prevalence is considered to be 0.3% among general population and 1% in population over 60 years of age.[3] Nowadays PD is differentiated from other causes of parkinsonism mostly by clinical features and developed criteria such as the MDS-PD criteria (Movement Disorder Society clinical diagnostic criteria for Parkinson Disease).[4] Tremor alone is seen as a common neurological finding. Other diseases such as essential tremor (ET) could present with similar signs and symptoms; turning the diagnosis into a dilemma for clinicians specially when the tremor is the dominant symptom.[5,6]

Methods

Results

Conclusion