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Multicenter Evaluation Of Parkinson's Disease Progression Using 123- I I-Ioflupane SPECT: Update From The Parkinson's Progression Marker Initiative Trial

Seibyl, J; Jennings, D; Coffey, C; Marek, K
 
2014-06-09
MDS: Stockholm, Sweden
Download Presentation: 246 MDS-2014-Presentation-Seibyl.pdf
 
Abstract:
Objective:
This study is an ongoing assessment of within subject changes of dopamine transporter SPECT imaging in a large patient Parkinson's disease (PD) cohort followed longitudinally over two years.

Background:
The Parkinson's progression marker initiative (PPMI) is an international, multicenter, longitudinal study assessing biochemical, clinical, and imaging biomarkers of disease progression.

Methods:
Baseline (n= 298), one year (n=298), and two year (n=117) 123 -I Ioflupane SPECT scans were acquired from 22 centers. Data were reconstructed, attenuation corrected, and analyzed by the imaging core lab using a standardized volume of interest template for extraction of regional count densities in the left and right caudate and putamen. A subset of subjects had an additional, completely automated VOI analysis. Striatal binding ratios (SBR) were calculated using an occipital lobe reference region. Mean percent SBR (% SBR) changes in mean, ipsilateral, and contralateral striatum were calculated.

Results:
PD subjects at baseline had a mean age of 61.7 y and an average disease duration of 6.6 months. The mean total UPDRS score was 31.9 (range 6-72) at baseline. For all 298 subjects baseline to year 1 percent change of mean average SBR (left and right caudate and putamen) was ?12.6%?±?15.6. Ipsilateral and contralateral striatum showed ?13.6%?±?16.6% and ?11.2%?±?17.5% change, respectively. No significant differences were noted between ipsilateral and contralateral striatum. For PD subjects with 3 SPECT scans (n=117), baseline to year 1 % SBR reduction was 13.6± 15.6%, while year 1 to year 2 scans showed a mean %SBR loss of 4.0± x16.2% (p<0.001).

Conclusions:
Quantitative DAT 123-I ioflupane SPECT imaging data acquired at baseline and two year follow-up in early stage PD demonstrate reductions in striatal ratios for mean, ipsilateral, and contralateral striatum. Mean Striatal Binding Ratios Baseline Year 1 Year 2 Striata 1.44 1.27 1.21 Ipsi Striatum 1.60 1.40 1.35 Contra Striatum 1.28 1.14 1.07
Symmetric rates of striatal signal loss are noted in these data with an average annualized SBR reduction of 10-11% per year annualized when combining subjects with 1 year and 2 year SPECT scans. Preliminary data suggests DAT signal loss is greater between baseline and year 1 compared with year 1 to year 2.