Statistical parametric mapping with F-18-dopa PET shows bilaterally reduced striatal and nigral dopaminergic function in early Parkinson's disease

Objective-To apply statistical parametric mapping to F-18-dopa PET data set s, to examine the regional distribution of changes in dopaminergic metaboli sm in early asymmetric Parkinson's disease. Methods-Thirteen normal volunteers (age 57.7 (SD 16.5) years; four women, n ine men) and six patients (age 50.3 (SD 13.5) years; three women, three men ) with asymmetric (right sided) Parkinson's disease were studied. Images fr om each dynamic dopa PET dataset were aligned and parametric images of F-18 -dopa influx (Ki) were created for each subject. The Ki images were transfo rmed into standard stereotactic space. The Ki values of the caudate and put amen on spatially normalised images were compared with the Ki values before normalisation. The application of statistical parametric mapping (SPM) all owed statistical comparison of regional Ki values on a voxel by voxel basis between healthy volunteers and patients with Parkinson's disease. Results-There was a strong correlation between the Ki values before and aft er spatial normalisation (r=0.898, p=0.0001). Significant decreases in the Ki values were found for the Parkinson's desease group throughout the entir e left putamen (p< 0.001) and focally in the dorsal right putamen (p< 0.001 ). Decreased Ki values were also shown bilaterally in the substantia nigra (p< 0.01). Conclusion-Using (SPM) and F-18-dopa PET, reductions in both striatal and n igral brain dopaminergic function could be demonstrated in early Parkinson' s disease.