Carole Lartizien1, Laurence Canaple2, Olivier Beuf3
1Universit de Lyon, CREATIS-LRMN, CNRS UMR 5220; Inserm U630; INSA-Lyon; Universit Lyon 1, Villeurbanne, France; 2Institut de Gnomique Fonctionnelle de Lyon, CNRS UMR 5241, ENS-Lyon, Lyon, France; 3Universit de Lyon, CREATIS-LRMN , CNRS UMR 5220; Inserm U630; INSA-Lyon; Universit Lyon 1, Villeurbanne, France
One of the main challenges to fully exploit the combination of PET with MRI is to achieve good co-registration between both modalities. A dedicated setup and co-registrated PET/MRI processing for abdominal images of the mouse acquired on two independent imaging systems (Bruker Biospec 7T and Raytest ClearPET) and based on external fiduciary markers was assessed. A mouse holder for both imaging systems was equipped with three non parallel fiduciary tubes. Different co-registration methods were evaluated on phantom experiments, based on rigid and non-rigid transformations and a semi-automated method using the external fiduciary markers. The semi-automated method and the non-rigid transform allowed the best co-registration. The protocol was then used on mouse models of digestive tumors. Visual analysis of the PET images of a mouse model developing spontaneous intestinal tumors, allowed in 2 out of the 3 mice, to localize tumors that were not seen on the MR images.