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Objective: We aimed to investigate the predictive value of pre-treatment 18 F-FDG PET/CT multi-metabolic parameters and tumor metabolic heterogeneity for gastric cancer prognosis., Methods: Seventy-one patients with gastric cancer were included. All patients underwent 18 F-FDG PET/CT whole-body scans prior to treatment and had pathologically confirmed gastric adenocarcinomas. Each metabolic parameter, including SUVmax, SUVmean, MTV, and TLG, was collected from the primary lesions of gastric cancer in all patients, and the slope of the linear regression between the MTV corresponding to different SUVmax thresholds (40% × SUVmax, 80% × SUVmax) of the primary lesions was calculated. The absolute value of the slope was regarded as the metabolic heterogeneity of the primary lesions, expressed as the heterogeneity index HI-1, and the coefficient of variance of the SUVmean of the primary lesions was regarded as HI-2. Patient prognosis was assessed by PFS and OS, and a nomogram of the prognostic prediction model was constructed, after which the clinical utility of the model was assessed using DCA., Results: A total of 71 patients with gastric cancer, including 57 (80.3%) males and 14 (19.7%) females, had a mean age of 61 ± 10 years; disease progression occurred in 27 (38.0%) patients and death occurred in 24 (33.8%) patients. Multivariate Cox regression analysis showed that HI-1 alone was a common independent risk factor for PFS (HR: 1.183; 95% CI: 1.010-1.387, P < 0.05) and OS (HR: 1.214; 95% CI: 1.016-1.450, P < 0.05) in patients with gastric cancer. A nomogram created based on the results of Cox regression analysis increased the net clinical benefit for patients. Considering disease progression as a positive event, patients were divided into low-, intermediate-, and high-risk groups, and Kaplan-Meier survival analysis showed that there were significant differences in PFS among the three groups. When death was considered a positive event and patients were included in the low- and high-risk groups, there were significant differences in OS between the two groups., Conclusion: The heterogeneity index HI-1 of primary gastric cancer lesions is an independent risk factor for patient prognosis. A nomogram of prognostic prediction models constructed for each independent factor can increase the net clinical benefit and stratify the risk level of patients, providing a reference for guiding individualized patient treatment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To investigate the value of dynamic metabolic curves and artificial neural network prediction models based on 18F-FDG PET multiphase imaging in differentiating nonspecific solitary pulmonary lesions., Methods: This study enrolled 71 patients with solitary pulmonary lesions (48 malignant and 23 benign lesions) who underwent multiphase 18F-fluorodeoxyglucose (18F-FDG)-PET/CT imaging. We recorded information on age, sex and uniformity of FDG uptake, measured standardized uptake value, metabolic tumor volume and total lesion glycolysis at various time points, and calculated individual standardized uptake values, retention index (RI) and slope of metabolic curve. Variables with high diagnostic efficiency were selected to fit dynamic metabolic curves for various lesions and establish different artificial neural network prediction models., Results: There were no significant differences in the retention index, metabolic tumor volume, total lesion glycolysis or sex between benign and malignant lesions; standardized uptake values, the slopes of five metabolic curves, uniformity of FDG uptake, and age showed significant differences. Dynamic metabolic curves for various solitary pulmonary lesions exhibited characteristic findings. Model-1 was established using metabolic parameters with high diagnostic efficacy (area under the curve, 83.3%). Model-2 was constructed as Model-1 + age (area under the curve, 86.7%), whereas Model-3 was established by optimizing Model-2 (area under the curve, 86.0%)., Conclusions: Dynamic metabolic curves showed varying characteristics for different lesions. Referring to these findings in clinical work may facilitate the differential diagnosis of nonspecific solitary pulmonary lesions. Establishing an artificial neural network prediction model would further improve diagnostic efficiency., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: To develop nomograms that combine clinical characteristics, computed tomographic (CT) features and 18F-fluorodeoxyglucose PET (18F-FDG PET) metabolic parameters for individual prediction of epidermal growth factor receptor (EGFR) mutation status and exon 19 deletion mutation and exon 21 point mutation (21 L858R) subtypes in lung adenocarcinoma., Methods: In total 124 lung adenocarcinoma patients who underwent EGFR mutation testing and whole-body 18F-FDG PET/CT were enrolled. Each patient's clinical characteristics (age, sex, smoking history, etc.), CT features (size, location, margins, etc.) and four metabolic parameters (SUVmax, SUVmean, MTV and TLG) were recorded and analyzed. Logistic regression analyses were performed to screen for significant predictors of EGFR mutation status and subtypes, and these predictors were presented as easy-to-use nomograms., Results: According to the results of multiple regression analysis, three nomograms for individualized prediction of EGFR mutation status and subtypes were constructed. The area under curve values of three nomograms were 0.852 (95% CI, 0.783-0.920), 0.857 (95% CI, 0.778-0.937) and 0.893 (95% CI, 0.819-0.968) of EGFR mutation vs. wild-type, 19 deletion mutation vs. wild-type and 21 L858R vs. wild-type, respectively. Only calcification showed significant differences between the EGFR 19 deletion and 21 L858R mutations., Conclusion: EGFR 21 L858R mutation was more likely to be nonsolid texture with air bronchograms and pleural retraction on CT images. And they were more likely to be associated with lower FDG metabolic activity compared with those wild-types. The sex difference was mainly caused by the 19 deletion mutation, and calcification was more frequent in them., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Myxoid leiomyosarcoma is a malignant tumor that originates from the mesenchymal tissue with extensive mucoid degeneration. It usually occurs in the uterus; occurrences from other tissues are extremely rare. Here we report the FDG PET/CT findings and clinicopathological of primary pleura myxoid leiomyosarcoma in a 51-year-old man.

Rationale: Mucosa-associated lymphoid tissue (MALT) lymphoma is an extranodal low-grade B cell lymphoma that generally exhibits an indolent clinical course. Currently, the application of F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) in MALT lymphoma is still controversial. Herein, we reported a case of using F-FDG PET/CT for staging and response assessment of primary parotid MALT lymphoma with multiple sites involvement. As far as we know, there are no similar case reports have been published before., Patient Concerns: A 71-year-old woman, who received mass resection twice during the past 2 years due to the repeatedly relapse of facial painless masses and diagnosed as reactive lymphoid hyperplasia by pathologic tests. However, the pathological diagnosis was then changed to primary parotid MALT lymphoma after left parotidectomy operation because of a new mass found in her left parotid. Four months later, the right eyelid of the patient swelled with a blurred vision. Then, F-FDG PET/CT scan was performed for staging, and the imaging results showed an abnormal increase of F-FDG uptake in multiple sites including bilateral ocular adnexal, lungs, pleura, occipital subcutaneous tissue, left kidney, and lymph nodes., Diagnoses: The patient was diagnosed as primary parotid MALT lymphoma with Ann Arbor stage of IVA based on the F-FDG PET/CT findings., Interventions: The patient received 4 cycles of chemotherapy, followed by a partial metabolic remission (PMR), which was determined by interim F-FDG PET/CT, and finally additional 2 cycles of chemotherapy., Outcomes: The follow-up study illustrated that the patient had been alive and doing well at 12 months after chemotherapy., Lessons: Although MALT lymphoma normally localizes in the primary organs, the involvement of multiple organs and lymph nodes is possible. The use of PET/CT demonstrated significant clinical values in the accurate staging and response assessment of F-FDG-avid MALT lymphoma. It is potentially useful for indicating the progress and transformation of MALT lymphoma, and guidance in localization of pathological biopsy. It is also helpful for clinicians to choose reasonable treatment strategy and improve the prognosis of patients.

Purpose: Advanced gastric cancer (AGC) and primary gastric lymphoma (PGL) are the two most common malignant tumors of the stomach. Conventional imaging examinations have difficulty distinguishing the two. This study explored the values of multiple parameters and visual assessment of 18F-fluorodeoxyglucose(18F-FDG) uptake heterogeneity of positron emission tomography/computed tomography(PET/CT) for differentiating between AGC and PGL. Methods: This retrospective study included 70 AGC and 26 PGL patients, all of whom had undergone 18F-FDG PET/CT before treatment. We analyzed the differences between AGC and PGL in the distribution of metastatic lesions and multiple metabolic parameters, including the maximum standardized uptake value (SUVmax), SUVmax/maximal thickness(THKmax), metabolic tumor volume and total lesion glycolysis (TLG). In addition, 18F-FDG uptake heterogeneity was visually assessed using a visual scoring method and a method of measuring SUVmax differences (SUVmax-d). Results: The most common metastasis of AGC patients were liver, bone, peritoneal and proximal lymph nodes; PGL patients had fewer peritoneal metastases and lymph node metastasis could appeared to be "skip metastasis." The metabolic parameters—SUVmax, SUVmax/THKmax and TLG—were higher in patients who had PGL, especially in diffuse large B-cell lymphoma (DLBCL). In the visual assessment of 18F-FDG uptake heterogeneity, the measurements of SUVmax-d in PGL were significantly higher than in AGC. Receiver operating characteristics curve analysis suggested that SUVmax has the highest comprehensive diagnostic efficiency due to having the highest value of area under the curve and the highest accuracy (77.2%). Conclusion: 18F-FDG PET/CT had a high diagnostic efficiency for discrimination of AGC and PGL, especially between DLBCL and other pathological subtypes. Visual assessment used to evaluate 18F-FDG uptake heterogeneity could help to distinguish the two types of tumors. In addition, our innovative method of measuring the heterogeneity of 18F-FDG uptake—namely, SUVmax-d—could contribute to identification of the two tumor types and should have its significance clarified by future studies. [ABSTRACT FROM AUTHOR]