RT Journal Article SR Electronic T1 Lung cancer imaging with respiratory motion-compensated simultaneous PET/MR JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1417 OP 1417 VO 57 IS supplement 2 A1 Joyita Dutta A1 Georges El Fakhri A1 Quanzheng Li YR 2016 UL http://jnm.snmjournals.org/content/57/supplement_2/1417.abstract AB 1417Objectives Motion artifacts introduced by respiration degrade both the quality and quantitative accuracy of thoracic PET images. The goal of this study is to evaluate the efficacy of motion-compensated simultaneous PET/MR in lung cancer imaging.Methods Simultaneous PET/MR imaging was performed on subjects with cancerous lesions in one or both lungs. [18F]FDG PET list-mode data and MR k-space data were simultaneously acquired using a Golden-angle RAdial Navigated Gradient Echo (GRANGE) pulse sequence. The MR acquisition parameters in the studies were as follows: TR 3.3 ms/slice, bandwidth 1 kHz/pixel, readout oversampling factor of 2,256 samples per radial line, and 26 coronal slices with a slice thickness of 8 mm and with 4000 radial lines per slice. The PET list-mode events and MR k-lines were grouped into six amplitude-based gates per respiratory cycle. Gated MR images were reconstructed using the k-t FOCUSS reconstruction technique. Non-rigid registration based on diffeomorphic demons was used to compute deformation fields from the reconstructed MR images. PET list-mode data were acquired for 7 min and binned into gated sinograms. Motion compensated (MC) PET images corresponding to the end-exhalation phase were reconstructed using the sinograms and deformation fields by employing a maximum a posteriori approach. As reference, one-gate (OG) and ungated (UG) PET images were computed.Results Overestimation of the volume and underestimation of the intensity of high-intensity features (such as lesions) are well-known consequences of motion-induced blurring. We therefore quantitatively compared the OG, UG, and MC cases by computing the lesion volume and lesion to background contrast-to-noise ratio (CNR). Our results indicate that, while, UG leads to an overestimation of lesion volume by 11%-38% relative to the OG case, MC exhibits a 2%-19% range for the same metric. Furthermore, MC leads to a CNR improvement of 19%-196% relative to OG and 6%-51% relative to UG.Conclusions Compensation of respiratory motion led to substantial enhancement of image contrast and reduction of variability in PET images of patients with lung lesions. Motion compensated simultaneous PET/MR is therefore promising for quantitative imaging of lung lesions.