Automatic deformable PET/MRI registration for preclinical studies based on B-splines and non-linear intensity transformation

作者：Bricq Stephanie; Kidane Hiliwi Leake; Zavala Bojorquez Jorge; Oudot Alexandra; Vrigneaud Jean Marc; Brunotte Francois; Walker Paul Michael; Cochet Alexandre; Lalande Alain

来源：MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, 2018, 56(9): 1531-1539.

DOI：10.1007/s11517-018-1797-0

• MRI
• PET
• Registration
• Preclinical imaging
• PCA
• B-splines

PET images deliver functional data, whereas MRI images provide anatomical information. Merging the complementary information from these two modalities is helpful in oncology. Alignment of PET/MRI images requires the use of multi-modal registration methods. Most of existing PET/MRI registration methods have been developed for humans and few works have been performed for small animal images. We proposed an automatic tool allowing PET/MRI registration for pre-clinical study based on a two-level hierarchical approach. First, we applied a non-linear intensity transformation to the PET volume to enhance. The global deformation is modeled by an affine transformation initialized by a principal component analysis. A free-form deformation based on B-splines is then used to describe local deformations. Normalized mutual information is used as voxel-based similarity measure. To validate our method, CT images acquired simultaneously with the PET on tumor-bearing mice were used. Results showed that the proposed algorithm outperformed affine and deformable registration techniques without PET intensity transformation with an average error of 0.72 +/- 0.44 mm. The optimization time was reduced by 23% due to the introduction of robust initialization. In this paper, an automatic deformable PET-MRI registration algorithm for small animals is detailed and validated.

• 出版日期2018-9