A new technique for pet slice orientation and MRI‐PET coregistration

We report and validate a technique for magnetic resonace imaging (MRI) positron emission tomography (PET) coregistration and the optimization of PET slice orientation that enhances and complements existing techniques. The technique depends on an external fiducial system and on software that models the relationship of the PET gantry with respect to a three‐dimensional (3D) MR reconstruction of each subject's brain anatomy. The technique offers the possibility of using individual neuroanatomical information to plan PET activation studies. Estimated 3D errors average 3 mm in [15O]H2O PET activation studies. In‐plane interinjection movement averages less than 1 mm. The resulting MRI‐PET coregistration provides a basis for bringing neuroanatomical information to bear on a number of issues critical for the interpretation of functional imaging studies. © 1995 Wiley‐Liss, Inc.