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Objectives: To evaluate the feasibility of equilibrium contrast-enhanced dual-energy CT (DECT), as compared with single-energy CT (SECT) and to calculate extracellular volume (ECV) fraction to predict the survival outcomes of pancreatic ductal adenocarcinoma (PDAC) patients with distant metastases (stage IV) treated with chemotherapy., Methods: The study cohort included a total of 66 patients with stage IV PDAC who underwent DECT before systemic chemotherapy between July 2014 and March 2017. Unenhanced and 120-kVp equivalent images during the equilibrium phase were used to calculate tumor SECT-derived ECV fractions, and iodine density images were obtained from equilibrium-phase DECT for DECT-derived ECV fractions. Correlations between SECT- and DECT-derived ECV fractions were identified using the Pearson correlation coefficient and Bland-Altman analysis. The effects of clinical prognostic factors and tumor SECT- and DECT-derived ECV fractions on progression-free survival (PFS) and overall survival (OS) were assessed by univariate and multivariate analyses using Cox proportional hazards models., Results: The correlation between SECT- and DECT-derived ECV fractions was strong (r = 0.965; p < 0.001). The Bland-Altman plot between SECT- and DECT-derived ECV fractions showed a small bias (- 3.4%). Increasing tumor SECT- and DECT-derived ECV fractions were associated with a positive effect on PFS (SECT, p = 0.002; DECT, p = 0.007) and OS (DECT, p = 0.014; DECT, p = 0.015). Only tumor DECT-derived ECV fraction was an independent predictor of PFS (p = 0.018) and OS (p = 0.022) in patients with stage IV PDAC treated with chemotherapy on multivariate analysis., Conclusions: The ECV fraction determined by equilibrium contrast-enhanced DECT can potentially predict the survival of patients with stage IV PDAC treated with chemotherapy., Key Points: • Extracellular volume fraction of stage IV pancreatic ductal adenocarcinoma determined by dual-energy CT was strongly correlated to that with single-energy CT (r = 0.965, p < 0.001). • Tumor extracellular volume fraction was an independent predictor of progression-free survival (p = 0.018) and overall survival (p = 0.022). • Extracellular volume fraction determined by dual-energy CT could be a useful imaging biomarker to predict the survival of patients with stage IV pancreatic ductal adenocarcinoma treated with chemotherapy.

Objectives: To assess whether extracellular volume (ECV) fraction with equilibrium contrast-enhanced multidetector computed tomography (MDCT) predicts outcomes for unresectable pancreatic adenocarcinoma patients treated with chemotherapy METHODS: Sixty-seven patients (42 men, 25 women; mean age, 67.5 years; range, 45-83 years) with histologically confirmed surgically unresectable pancreatic adenocarcinoma underwent contrast-enhanced MDCT before systemic chemotherapy. Tumour contrast enhancement (CE) and ECV fraction were calculated using region-of-interest measurement within the pancreatic adenocarcinoma and aorta on unenhanced and equilibrium phase-enhanced CT. The effect on survival variables including age, sex, tumour location, tumour size, TNM stage, carbohydrate antigen (CA) 19-9, carcinoembryonic antigen (CEA), tumour CE and tumour ECV fraction was determined on univariate and multivariate analyses using Cox proportional hazards regression model., Results: Median overall survival was 10.5 months. On univariate analysis, elevated serum CA19-9 (hazard ratio (HR), 1.00; p = 0.006) and CEA (HR, 1.02; p = 0.011) levels were found to be associated with a negative effect on overall survival. Increasing tumour CE (HR, 0.98; p < 0.001) and ECV fraction (HR, 0.97; p = 0.001) were associated with a positive effect. Multivariate analysis revealed that only tumour ECV fraction was an independent predictor of overall survival (HR, 0.97; p = 0.012)., Conclusions: ECV fraction with equilibrium contrast-enhanced MDCT could be a useful imaging biomarker for predicting patient survival after chemotherapy for unresectable pancreatic adenocarcinoma., Key Points: • Tumour aggressiveness and response to therapy are influenced by the extravascular extracellular space. • Extracellular volume (ECV) fraction can be quantified with equilibrium contrast-enhanced CT. • Patients with higher tumour ECV fraction had better prognosis after chemotherapy.

Purpose: The aim of this study was to establish an evaluation system to monitor bone formation and beta-tricalcium phosphate (TCP) resorption in opening high tibial osteotomy (HTO)., Methods: From 2003 to 2005, opening HTO was performed in 36 patients using a Puddu plate and β-TCP blocks with 60 and 75 % porosity. Thirty-one patients were used for evaluation. All patients underwent CT examination at 2 weeks and 6 years. The CT image data were divided into three areas, and CT values of each area were analysed using the imaging software, Osirix., Results: CT image analysis at 2 weeks showed that the mean CT-attenuation values (in Hounsfield units) of the implanted area with β-TCP of 60 % porosity, the implanted area with β-TCP of 75 % porosity, and cancellous bone were, 1,694.0 ± 94.2, 1,010.9 ± 81.1, and 178.0 ± 45.1, respectively. Six years after surgery, these values were 574.1 ± 273.5, 168.8 ± 75.1, and 174.9 ± 69.3, respectively., Conclusion: β-TCP with 75 % porosity was completely resorbed and replaced by bone. β-TCP with 60 % porosity was resorbed, but approximately 1/3 still remained even 6 years after surgery. The imaging software, Osirix, enabled scanning of the whole area to measure CT values. This system is the first to quantitatively evaluate β-TCP resorption and bone formation in opening HTO., Level of Evidence: Laboratory studies.

In order to evaluate the ability of fibrochondrocytes to synthesize collagen and proteoglycan, human medial meniscal cells were cultured in a monolayer. Meniscal cells were prepared from the two regions (outer 1/3 and inner 2/3) in consideration of the difference in vascular supply, and articular chondrocytes were also obtained from the same knee joint. Regarding total collagen synthesis, regional differences were not found, but age-related differences were found in human medial meniscus. In contrast, proteoglycan synthesis revealed significant regional differences; meniscal cells from the inner 2/3 synthesized a greater amount of proteoglycan. After long-term monolayer culturing, proteoglycan synthesis by meniscal cells decreased in a time-dependent manner, and morphological changes to fibroblast-like cells were found. In the presence of transforming growth factor (TGF)-beta, proteoglycan synthesis increased in a dose-dependent manner. These findings suggest that the inner regions of the human meniscus contain cells with a chondrocytic phenotype.