@article {Ma3025, author = {Yutong Ma and Ying Liang}, title = {Comparison and Evaluation of Respiration-gated and Non-respiration-gated PET/CT Imaging in the Diagnosis of Liver Lesions}, volume = {62}, number = {supplement 1}, pages = {3025--3025}, year = {2021}, publisher = {Society of Nuclear Medicine}, abstract = {3025Purpose: This study aims to compare the lesion detectable rates, quantification and image quality among ungated (UG), Q.Static respiration-gated (QSRG) and Q.Freeze respiration-gated (QFRG) PET/CT scans. The clinical application of respiration-gated PET/CT in the diagnosis of liver lesions was evaluated. Methods: Fifty-eight patients with suspected liver nodules (199 18F-FDG-avid lesions in total) underwent respiration gated scans from 2019 Nov to 2020 Dec in our hospital were retrospectively enrolled in this study. Nine patients were excluded due to the failure of respiration-gated scans. The SUVmax, metabolic tumor volume (MTV), SUVmean, long diameter of liver lesions and liver background SUVmean were collected from the PET images and then compared under UG, QSRG and QFRG images. The detection rate, the signal-to-noise rate (SNR) and the contrast-to-noise rate (CNR) were further analyzed. Results: 187, 193, 199 liver lesions were detected under UG, QSRG and QFRG scans respectively. The SUVmax, SUVmean, target-to-background ratios and CNR under UG scans were 6.82{\textpm}2.78, 4.55{\textpm}1.85, 3.54{\textpm}1.59, 24.19{\textpm}14.9 (P\<0.05), which were lower than those under QSRG scans (7.50{\textpm}2.91, 4.98{\textpm}1.93, 3.98{\textpm}1.68, 32.87{\textpm}19.2, P\<0.05) and QFRG scans (8.38{\textpm}3.52, 5.82{\textpm}2.47, 4.69{\textpm}2.17, 32.25{\textpm}23.0, P\<0.05). However, UG group has the highest MTV and long diameter (11.78{\textpm}28.7, 2.35{\textpm}1.39, P\<0.05), compared with QSRG group (10.73{\textpm}27.7, 2.22{\textpm}1.37, P\<0.05) and QFRG group (8.64{\textpm}22.8, 2.19{\textpm}1.29, P\<0.05). The SNR under UG scans (9.26{\textpm}1.89, P\<0.05) was lower than that under QSRG(11.29{\textpm}2.31, P\<0.05). There is no significant difference in the long diameter and the SNR mean values among QSRG and QFRG scans. Conclusions: Compared with UG scans, liver lesions could be clearly visualized under the respiration-gated scans, with a higher detection rate, more measurable information and a more accurate quantification analysis.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/62/supplement_1/3025}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }