Jingjuan Wang1, Hongwei Yang1, Bixiao Cui1, Baoci Shan2,3, Jie Lu4,5. 1. Department of Radiology and Nuclear Medicine, Xuanwu Hospital Capital Medical University, 45 Changchun Street, Xicheng District, Beijing, 100053, China. 2. Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China. shanbc@ihep.ac.cn. 3. School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing, China. shanbc@ihep.ac.cn. 4. Department of Radiology and Nuclear Medicine, Xuanwu Hospital Capital Medical University, 45 Changchun Street, Xicheng District, Beijing, 100053, China. imaginglu@hotmail.com. 5. Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China. imaginglu@hotmail.com.
Abstract
PURPOSE: To investigate the potential effects of MRI protocols on brain FDG uptake in simultaneous PET/MR imaging. METHODS: Seventy healthy subjects and ten patients with temporal lobe epilepsy were enrolled. Healthy subjects were divided to three groups to undergo different PET/MR scan protocols: "continuous MRI" with MRI stimulation presented during the whole scan, "late MRI" with MRI stimulation started after 40 min glucose uptake, and "no MRI" without MRI stimulation at all. Region-wise and voxel-wise differences in FDG uptake among the three protocols were compared. All epilepsy patients were scanned with the "continuous MRI" scan protocol. The effects of MRI protocol stimulation on pathological interpretation were evaluated. RESULTS: Highest global averaged metabolism was found in the normal dataset with continuous MRI scan protocol (P < 0.05). Specifically, we observed higher FDG uptake in the primary auditory cortex, putamen, and lower FDG uptake in the occipital lobe and cerebellum during the "continuous MRI" scan protocol. However, MRI protocol stimulation after 40 min glucose uptake did not cause any significant differences in FDG uptake. Respectively compared to the normal dataset, patients with epilepsy showed consistent hypometabolism in the temporal lobe. Besides, significant metabolism changes in the primary auditory cortex, vermis, and occipital lobe were found in the "late MRI" protocol. CONCLUSION: The effects of MRI protocol on brain FDG uptake were varied. The effects, including from other practical setting, were conspicuous for scans where MRI protocol started immediately after glucose uptake, but would dramatically decrease to negligible 40 min later. Hence, it would be necessary for pathology studies to collect data from a normal control group using the same scan protocol for unbiased evaluation.
PURPOSE: To investigate the potential effects of MRI protocols on brain FDG uptake in simultaneous PET/MR imaging. METHODS: Seventy healthy subjects and ten patients with temporal lobe epilepsy were enrolled. Healthy subjects were divided to three groups to undergo different PET/MR scan protocols: "continuous MRI" with MRI stimulation presented during the whole scan, "late MRI" with MRI stimulation started after 40 min glucose uptake, and "no MRI" without MRI stimulation at all. Region-wise and voxel-wise differences in FDG uptake among the three protocols were compared. All epilepsy patients were scanned with the "continuous MRI" scan protocol. The effects of MRI protocol stimulation on pathological interpretation were evaluated. RESULTS: Highest global averaged metabolism was found in the normal dataset with continuous MRI scan protocol (P < 0.05). Specifically, we observed higher FDG uptake in the primary auditory cortex, putamen, and lower FDG uptake in the occipital lobe and cerebellum during the "continuous MRI" scan protocol. However, MRI protocol stimulation after 40 min glucose uptake did not cause any significant differences in FDG uptake. Respectively compared to the normal dataset, patients with epilepsy showed consistent hypometabolism in the temporal lobe. Besides, significant metabolism changes in the primary auditory cortex, vermis, and occipital lobe were found in the "late MRI" protocol. CONCLUSION: The effects of MRI protocol on brain FDG uptake were varied. The effects, including from other practical setting, were conspicuous for scans where MRI protocol started immediately after glucose uptake, but would dramatically decrease to negligible 40 min later. Hence, it would be necessary for pathology studies to collect data from a normal control group using the same scan protocol for unbiased evaluation.