Surgical resection failed to achieve CA19-9 normalization in the high PET group and distant recurrence was frequent. This suggests the potential for residual cancer at distant sites, even after curative resection. Stronger preoperative systemic chemotherapy is preferred for the high PET group patients.

ObjectivesMetabolic tumor volume (MTV) on 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is a promising prognostic predictor in pancreatic ductal adenocarcinoma (PDAC). However, the optimal segmentation method and threshold value to determine MTV for PDAC are still unclear. We explored the optimal method and threshold value for the prognostic value of MTV measured on pre-treatment 18F-FDG-PET/CT.MethodsSeventy-three patients with resected PDAC who underwent 18F FDG-PET/CT before surgical resection were enrolled. MTV values of the tumor were measured on FDG-PET/CT by the two fixed-threshold methods using threshold values as 2.0, 2.5, 3.0, and 3.5 for the absolute method and 35%, 40%, 42%, 45%, and 50% for the relative method. Receiver operating characteristic curve analysis for prediction of 1-year survival rates was conducted for determining the optimal threshold values, and we selected the optimal method and threshold value considering area under the curve. The prognostic values of each FDG-PET/CT parameter for disease-specific survival and recurrence-free survival were assessed with Kaplan–Meier method and Cox proportional hazard models.ResultsIn receiver operating characteristic curve analysis, MTV by the fixed-absolute threshold method based on a threshold value of 3.5 (MTV3.5) performed best in our study with area under the curve 0.724, sensitivity of 65%, and specificity of 75%. In univariate and multivariate analyses, MTV3.5 was significantly associated with disease-specific and recurrence-free survival.ConclusionsMTV3.5 by absolute threshold on pre-treatment FDG-PET/CT was the best independent prognostic predictor in resectable PDAC compared with other absolute threshold values and relative threshold values.

Although it is known that health is not merely the absence of disease, the positive aspects of mental health have been less comprehensively researched compared with its negative aspects. Subjective well-being is one of the indicators of positive psychology, and high subjective well-being is considered to benefit individuals in multiple ways. However, the neural mechanisms underlying individual differences in subjective well-being remain unclear, particularly in terms of brain microstructural properties as detected by diffusion tensor imaging. The present study aimed to investigate the relationship between measurements of diffusion tensor imaging (mean diffusivity and fractional anisotropy) and the degree of subjective well-being as measured using a questionnaire. Voxel-based analysis was used to investigate the association between mean diffusivity and subjective well-being scores in healthy young adults (age, 20.7 ± 1.8 years; 695 males and 514 females). Higher levels of subjective well-being were found to be associated with lower mean diffusivity in areas surrounding the right putamen, insula, globus pallidus, thalamus, and caudate. These results indicated that individual subjective well-being is associated with variability in brain microstructural properties.