Generative atlases and atlas selection for C11-PIB PET-PET registration of elderly, mild cognitive impaired and Alzheimer disease patients

beta-amyloid (Abeta) plaques are one of the neuropathological hallmarks of Alzheimer´s disease (AD) and can be quantified using the marker ¹¹C PiB. The registration of ¹¹C PIB PET images to an atlas allows spatial normalization and statistical comparisons. This generally involves a co-registration of the PET and MR which is then registered to an MR atlas. The use of PET to PET atlas registration is much less common, although important as MR scans are not always available. In this paper we present a study on using PET to PET atlas registration with the corresponding MR registration used as the reference standard. Average affine and non-rigidly aligned PET Atlases were created, as well as a principal component based generative atlases. From this work we found that the use of multiple registrations to a generative affine ¹¹C PIB PET atlas obtains the best results, with a mean translation error of 1.67 mm, and average point to point error around the cortex of 2.77 mm. As the obtained results are almost the same as using PET-MR co-registration and propagation to an atlas, and in some cases qualitatively they can appear better, we believe this may be a suitable approach for ¹¹C PIB PET registration, which may avoid the need for acquiring the MR and performing multimodality registration.