A low ADC value reflects the morphological and biological features of prostate cancer. Analyzing the ADC value may make it possible to more precisely predict the cancer aggressiveness of each focus before treatment.

Purpose The aim of this study was to investigate the diagnostic performance of whole-body [11C]acetate PET/CT in less aggressive or indolent lymphomas, wherein [18F]FDG PET/CT would exhibit limited sensitivity. Methods Between September 2016 and May 2018, we prospectively evaluated 17 patients (9 men, 8 women; mean age [range], 71 [45–87] years) with pathologically proven less aggressive or indolent lymphomas according to Non-Hodgkin's Lymphoma Classification Project, using both [18F]FDG PET/CT and [11C]acetate PET/CT (performed on the same day). Detected nodal lesions were recorded according to the Ann Arbor classification. Extranodal (EN) lesions were also evaluated. We compared whole-body lesion detection between [18F] FDG PET/CT and [11C]acetate PET/CT using the McNemar test. Results In all patients, significantly more nodal and EN lesions were detected using [11C]acetate PET/CT than [18F]FDG PET/CT (nodal: 84 vs 64 regions; P < 0.001; EN: 26 vs 19 regions, P = 0.039). Bone lesions were detected in 8 and 5 patients using [11C]acetate PET/CT and [18F]FDG PET/CT, respectively (P = 0.25). Among the 14 patients (82.4%) who underwent bone marrow biopsy, bone marrow involvement was detected with sensitivities of 100% (6/6 patients) and 80% (5/6 patients) using [11C]acetate PET/CT and [18F]FDG PET/CT, respectively. Multiple areas of focal uptake in the spleen of 1 patient were exhibited on [18F]FDG PET/CT but not [11C]acetate PET/CT. Conclusions [11C]acetate PET/CT exhibited greater sensitivity than [18F]FDG PET/CT for lesion detection in patients with less aggressive or indolent lymphomas, thus promising applicability as a physiological tracer in the study of such lesions.

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Background: [F-18]fluorodeoxyglucose positron emission tomography/computed tomography is routinely used for assessing Takayasu arteritis patients. However, extra-vessel [F-18 ]fluorodeoxyglucose uptake has not been evaluated in detail in these patients. We aimed to describe the extent and distribution of extra-vascular [F-18]fluorodeoxyglucose uptake on positron emission tomography/computed tomography in Takayasu arteritis patients. Seventy-three [F-18]fluorodeoxyglucose positron emission tomography/computed tomography scans from 64 consecutive Takayasu arteritis patients (59 women, mean age, 35.4 years; range, 13 to 71 years) and 40 scans from age-matched controls (36 women, mean age, 37.8 years; range, 13 to 70 years) were examined. We graded [F-18]fluorodeoxyglucose uptake in large vessels using a 4-point scale and evaluated extra-vessel findings. Factors correlated with disease activity were examined. We evaluated the relationship between disease activity according to the National Institutes of Health score with extra-vessel findings, as well as other inflammatory markers (e.g., white blood cell count and C-reactive protein level). Results: Extra-vessel involvement was present in 50 of 73 (68.4%) scans, specifically at the following sites: lymph nodes, 1.4%; thyroid glands, 17.8%; thymus, 11.0%; spleen, 1.4%; vertebrae, 45.2%; and pelvic bones, 9.6%. Takayasu arteritis patients had higher [F-18]fluorodeoxyglucose uptake in the spine (P = 0.03) and thyroid glands (P = 0.003) than did controls; uptake in other regions was comparable between groups. Compared with inactive patients, those with active Takayasu arteritis had a higher number of [F-18]fluorodeoxyglucose uptake sites in the vasculature (P = 0.001). Finally, patients with a National Institutes of Health score of ≥ 1 had significantly higher extra-vascular involvement (P = 0.008). Conclusions: Extra-vessel [F-18]fluorodeoxyglucose uptake may be present in the context of Takayasu arteritis-related inflammatory processes. Information on extravascular [F-18]fluorodeoxyglucose uptake may be useful for detecting and evaluating inflammatory processes when interpreting positron emission tomography/computed tomography scans obtained from Takayasu arteritis patients.

Objective This study aimed to clarify the relationship between tumor redox reaction evaluated by 62Cu-diacetyl-bis (N4-methylthiosemicarbazone) (62Cu-ATSM) PET/computed tomography (CT) and disease-free survival (DFS) in patients with primary diffuse large B-cell lymphoma of the central nervous system (DLBCL-CNS). Methods Fifteen consecutive patients with histologically confirmed DLBCL-CNS underwent preoperative 62Cu-ATSM PET/CT and 18F-fluorodeoxyglucose (FDG) PET/CT. Statistical features of seven first-order parameters, including the standardized uptake value (SUV); 12 second-order parameters, including gray-level co-occurrence matrices and gray-level zone size matrices; and 5 high-order parameters, including neighborhood gray-tone difference matrices, were calculated from the volume of interest. We compared DFS with parameters, including SUVmax and tumor-to-background (T/B) ratio of FDG, and SUVmax, T/B ratio, and other textural features of 62Cu-ATSM. Results The mean follow-up duration after PET/CT was 458 (range, 41–1071) days. The SUVmax of FDG was significantly higher than that of 62Cu-ATSM (P = 0.001), but the T/B ratio was not significantly different between the scans (3.49 ± 2.29 vs 2.48 ± 1.18; P = 0.244). A Mantel–Cox log-rank test revealed no significant association between SUVmax of FDG and DFS (P = 0.641). A high SUVmax of 62Cu-ATSM had a tendency of shorter DFS (P = 0.055). Total lesion reduction, reductive tumor volume, and T/B ratio of 62Cu-ATSM were significantly correlated with poor DFS by univariate analysis (P = 0.049, 0.031, and 0.007, respectively). Neighborhood gray-level co-occurrence matrix dissimilarity was significantly correlated with poor DFS (P = 0.015). Conclusions Metabolic and textural features derived from pretreatment 62Cu-ATSM PET/CT could be used for predicting DFS and establishing a novel treatment strategy in DLBCL-CNS patients.