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Abstract #3737

Comparison of the Accuracy of PET/CT and PET/MR Spatial Registration in Multiple Metastatic Lesions

Linda DeMello1, Rajan Rakheja1, Christopher B. Glielmi2, Christian Geppert3, Hersh Chandarana4, Kent Friedman1

1Radiology, New York University School of Medicine, New York, United States; 2MR R&D Collaborations, Siemens Healthcare, New York, United States; 3MR R&D Collaborations, Siemens Medical Systems, New York, United States; 4Radiology, NYU Langone Medical Center, New York, United States

This study was performed to compare the accuracy of spatial registration of PET/CT and PET/MR in patients with FDG-avid metastatic lesions. Thirteen patients underwent PET/CT followed by PET/MR, and the spatial coordinates of the visually estimated centers of nineteen metastatic lesions were measured. Total distance between the isocenters was calculated, along with averages and standard deviations. Morphologic PET/MR sequences showed significantly more accurate spatial registration than PET/CT, likely secondary to simultaneous acquisition of PET and MR data. However, EPI-based DWI sequences demonstrated significant misregistration compared to PET/CT, likely due to respiratory motion and the inherent spatial distortion of DWI.