MR-PET IMAGE COREGISTRATION FOR QUANTITATION OF STRIATAL DOPAMINE D-2RECEPTORS

Purpose: Our goal was to assess the utility of MR-PET image coregistra tion to quantify dopamine D-2 receptors in striatum. Method: Twenty-ni ne normal subjects were investigated with PET and [C-11]raclopride and with MRI. D-2 receptors were quantified using the ratio of the distri bution volume in striatum to that in cerebellum. Measures obtained usi ng regions selected directly from the PET images were compared with th ose obtained from MR images and then projected to coregistered PET ima ges, Results: There were no differences between measures selected from the PET images (3.9 +/- 0.5) and those from the MR images (3.9 +/- 0. 65), The values for these two measures were significantly correlated a nd corresponded to r = 0.9, p < 0.0001. Conclusion: Regions of interes t selected directly from PET images, where there is a large contrast b etween the region of interest and background, as for the case of dopam ine D-2 ligands, are almost identical to those obtained from coregiste red MR images.