Investigating the role of ^99mTc-TRODAT-1 SPECT imaging in idiopathic Parkinson’s disease

Abstract

Objective: To investigate the role of ^99mTc-TRODAT-1 SPECT in diagnosis and assessing severity of idiopathic Parkinson’s disease (PD). Methods: Thirty-eight patients with primary, tentative diagnosis of PD and eighteen age-matched normal controls were studied with ^99mTc-TRODAT-l SPECT imaging. The regions of interests (ROIs) were drawn manually on cerebellum (CB), occipital cortex (OC) and three transverse plane slice-views of striatums, the semiquantitative BG (back-ground)/[(OC+CB)/2] were then calculated. Results: A lower uptake of ^99mTc-TRODAT-1 in striatums were displayed in thirty-six out of thirty-eight PD patients by visual inspection, compared to controls. In twenty-four PD cases with HYS (Hoehn and Yahr scale) stage I, a greater loss of DAT uptake was found in striatum and its subregions contralateral striatum to the affected limbs than in the same regions of the controls, although the striatal uptake was bilaterally reduced. Using Spearman correlation analysis showed that the reduction of the uptake ratios significantly correlated with the UPDRS in striatum and all its subregions in the PD group (P<0.05), a similar change was also found in the putamen by using the rating scale of Hoehn and Yahr (P<0.05). However, analysis of variance (ANOVA) did not show any relationship between the decreasing uptake of ^99mTc-TRODAT-1 and increasing severity of PD patients, although the specific uptake of ^99mTc-TRODAT-1 was continuously decreased in the striatum by visual inspection with the progress of PD from HYS stage I to III. Conclusion: ^99mTc-TRODAT-1 SPECT imaging may serve as a useful method for improving the correct diagnosis of PD. In assessing the role of ^99mTc-TRODAT-1 SPECT in disease severity of PD, UPDRS can offer a comprehensive index, although the Hoehn and Yahr assessment may be available in part.