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Objective: Integrated positron emission tomography/magnetic resonance imaging (PET/MRI) scanners provide combined MR-based anatomic and metabolic image information. The aim of this study was to evaluate qualitative and quantitative diagnostic performance of PET/MR with (18)fluoro-2-deoxyglucose ((18)F-FDG) using a diagnostic MR sequence in patients with abdominal and pelvic tumors, compared to positron emission tomography/computed tomography (PET/CT). Materials and Methods: Forty five patients underwent a single-injection ((18)F-FDG), dual-imaging protocol including whole-body PET/CT and subsequent regional PET/MR hybrid imaging. A regional PET/MR scan followed the PET/CT. Images from both modalities were analyzed using a 3-point scale for PET/CT and PET/MR image quality, image alignment, and lesion visibility on PET images. PET-CT/PET-MR functional and anatomical correlation was analyzed. Results: A total of 66 lesions were studied, from which 63 were identified using PET/CT and 59 were identified using PET/MR. The (18)F-FDG PET images had good diagnostic quality (P<0.001); alignment was found to be excellent in PET/MR data as well as PET/CT data (P=0.102), and there was no difference in lesion visibility (P=0.18). The average rating score regarding anatomical correlation for PET-positive lesions was 2.75 for combined MR sequence images and 2.04 for CT, with a significant difference (P=0.317), Standard uptake value (SUV) for focal lesions had excellent correlation (SUVmax/mean: R=0.948/0.948); furthermore, the SUVmean of background organs combined, bone marrow and the muscle tissue showed good correlation (R=0.329/0.398/0.298). No correlations were found in the liver and spleen. Conclusions: PET/MR with diagnostic MR sequence was able to detect abdominal and pelvic lesions and had good image quality compared to PET/CT. SUVmax and SUVmean values in focal lesions, and the SUVmean of background organs generally correlated well in abdominal and pelvic oncology patients examined using PET/CT and PET/MRI. [ABSTRACT FROM AUTHOR]

Objective: To clarify the usefulness of 18F-FDG PET/CT for detecting primary gastric cancer via gastric distention using a mixture of milk and Diatrizoate Meglumine. Materials and methods: A total of 68 patients (male: 47, female: 21; age: 41–87 years) suspected of gastric carcinoma underwent 18F-FDG PET/CT imaging. After whole-body PET/CT imaging in a fasting state, the patients drank a measured amount of milk with Diatrizoate Meglumine. Local gastric district PET/CT imaging was performed 30min later. The imaging was analyzed by semi-quantitative analysis, standardized uptake value (SUV) of the primary tumor was measured in a region of interest. The diagnosis results were confirmed by gastroscopy, pathology, and follow-up results. Results: Of the 68 patients, 56 malignant gastric neoplasm patients (male: 37, female: 19) were conformed. The sensitivity, specificity, positive predictive value and negative predictive value of fasting whole-body PET/CT imaging for a primary malignant tumor were 92.9%, 75.0%, 94.5%, and 69.0%, respectively. The values for distension with a mixture of milk and Diatrizoate Meglumine were 91.1%, 91.7%, 98.1%, and 68.8%, respectively. The area under the curve was 0.919±0.033 and 0.883±0.066 for the diagnosis of gastric cancer with SUVmax in a fasting state and after intake of mixture respectively, the differences were not statistically significant (P =0.359). Using gastric distension with a mixture of milk and Diatrizoate Meglumine, the mean ratio of the lesion's SUVmax to the adjacent gastric wall SUVmax increased significantly from 3.30±3.05 to 13.50±15.05, which was statistically significant (P <0.001). Conclusions: 18F-FDG PET/CT imaging is highly accurate for the diagnosis of primary gastric carcinoma. Gastric distention can display the lesions more clearly, however, it cannot significantly improve diagnostic accuracy. [ABSTRACT FROM AUTHOR]