Characterization of the impact to PET quantification and image quality of an anterior array surface coil for PET/MR imaging

Object: The aim of this study was to determine the impact to PET quantification, image quality and possible diagnostic impact of an anterior surface array used in a combined PET/MR imaging system. Materials and methods: An extended oval phantom and 15 whole-body FDG PET/CT subjects were re-imaged for one bed position following placement of an anterior array coil at a clinically realistic position. The CT scan, used for PET attenuation correction, did not include the coil. Comparison, including liver SUV_mean, was performed between the coil present and absent images using two methods of PET reconstruction. Due to the time delay between PET scans, a model was used to account for average physiologic time change of SUV. Results: On phantom data, neglecting the coil caused a mean bias of -8.2 % for non-TOF/PSF reconstruction, and -7.3 % with TOF/PSF. On clinical data, the liver SUV neglecting the coil presence fell by -6.1 % (±6.5 %) for non-TOF/PSF reconstruction; respectively -5.2 % (±5.3 %) with TOF/PSF. All FDG-avid features seen with TOF/PSF were also seen with non-TOF/PSF reconstruction. Conclusion: Neglecting coil attenuation for this anterior array coil results in a small but significant reduction in liver SUV_mean but was not found to change the clinical interpretation of the PET images.