Voxel-based analysis of the effect of age and gender on dopamine transporter availability in a large sample from a Japanese database of 123I-ioflupane SPECT

1648 Objectives: Dopamine transporter (DAT) imaging, particularly 123I-ioflupane (123I-FP-CIT) brain single photon emission computed tomography (SPECT), has been widely used in clinical practice for the diagnosis of Parkinson-related disorders, such as Parkinson’s disease and dementia with Lewy bodies. Several studies have suggested the effects of aging and gender on DAT availability in healthy subjects; however, only a few have addressed these effects by a voxel-based approach. Therefore, the main aim of this study is to perform a voxel-based analysis of the effect of age and gender on striatal DAT availability using a large-scale multi-site database of 123I-ioflupane brain SPECT in Japan. Methods: Five hundred and ten 123I-ioflupane brain SPECT data from 256 healthy subjects (116 men and 140 women, age range 30-83 years), acquired from 8 different sites across Japan were examined. All SPECT data with neither attenuation nor scatter correction were calibrated using a striatum phantom experiment for each SPECT system. Specific binding ratio (SBR) in the striatum was calculated using the Southampton method (Tossici-Bolt et al, 2006). Subsequently, a voxel-based analysis was performed using the statistical parametric mapping (SPM12). 123I-Ioflupane SPECT data were coregistered to the individual’s MRI 3D-T1 weighted image, and spatially normalized to the Montreal Neurologic Institute space. The maximal value of the bilateral striatal SBR was inserted to the maximal counts of the striatum of normalized SPECT data. After the images were smoothed in 10 mm, multiple regression and two-sample t-test were applied to explore the age effect and gender difference, respectively. The absolute value of SBR less than 1 was masked out. Statistical significance was set at family-wise error, p Conclusions: The present results demonstrated an overall negative aging effect on striatal DAT availability in the largest sample of healthy subjects studied till date, with men and women demonstrating different striatal subregional patterns of aging effect. In addition, the effect of gender was only observed in subjects over 50 years old, and in those subjects, subregional differences in the striatum was observed. These findings suggest differential physiological contributions of age and gender on DAT availability in the striatal subregions of the brains of healthy adults.