A triple-source CT system for micro-scale investigation of geological materials: A simulation study.

A triple-source CT system is proposed for micro-scale testing of geological materials. This study aims at reducing the projection acquisition time by two-thirds compared to a conventional single-source CT system. The proposed system with different positioning errors in the source-to-object distance (SOD) was simulated and tested using the Shepp-Logan phantom model, as well as slices of sand, glass beads, and concrete samples. Furthermore, the imaging quality of a single-source and the triple-source CT system with different dead detector pixels was compared. The results showed that within the maximum allowable positioning error, the pixel differences between the simulated and the original images are close to zero, and the structural similarities are greater than 0.96. In the presence of dead detector pixels, the quality of the simulated images in the triple-source CT system is superior to that of a single-source CT system. The presented triple-source CT system performs well in high-quality image reconstruction.

Retrospective analysis of T-lymphocyte subsets and cytokines in malignant obstructive jaundice before and after external and internal biliary drainage.

OBJECTIVE: To study changes in T lymphocyte subsets, cytokines, and liver enzymes in patients with malignant obstructive jaundice (MOJ) before and after external biliary drainage (percutaneous transhepatic cholangiography drainage, PTCD) and internal biliary drainage (percutaneous transhepatic insertion of biliary stents, PTIBS). METHODS: MOJ patients undergoing PTCD (n = 44) and PTIBS (n = 38) at our hospital were enrolled in the study from January 2017 until December 2019. Peripheral blood total bilirubin (TBIL), direct bilirubin (DBIL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), CD3+%, CD4+%, CD4+/CD8+ ratio, interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α were measured before and 1 week after biliary drainage. RESULTS: There was no significant difference in any parameter between the two groups before biliary drainage. TBIL, DBIL, AST and ALT following PTCD were significantly lower than before PTCD. By contrast, CD3+%, CD4+%, CD4+/CD8+ ratio, IL-2, IL-6 and TNF-α showed no significant difference before and 1 week after PTCD. TBIL, DBIL, AST, ALT, IL-6 and TNF-α were significantly lower following PTIBS than before PTIBS. CD3+%, CD4+%, CD4+/CD8+ ratio and IL-2 were significantly higher following PTIBS than before PTIBS. CONCLUSION: Both PTCD and PTIBS were effective for treatment of MOJ, but PTIBS was more beneficial for recovery of immune function.

A prospective study of risk factors for in-hospital mortality in patients with malignant obstructive jaundice undergoing percutaneous biliary drainage.

BACKGROUND: The in-hospital mortality rate in patients undergoing percutaneous transhepatic biliary drainage (PTBD) for malignant obstructive jaundice (MOJ) is high. There are few reports on the risk factors associated with hospital death after MOJ, with most of them being retrospective analyses of single factors. Therefore, this study aimed to assess pre-, intra-, and post-procedure risk factors that were independently associated with increased in-hospital mortality in MOJ patients who underwent PTBD. METHODS: One-hundred fifty-five patients with MOJ who underwent initial PTBD were included in this study. A total of 25 pre-, 4 intra-, and 6 post-procedure factors potentially related to in-hospital mortality were assessed by univariate and multivariate analyses. RESULTS: The in-hospital mortality rate was 16.8% (26/155). Of 25 pre-procedure variables analyzed, Child-Pugh classification C, creatinine level ≥6.93 µmol/L, and quality-of-life score (≤30) were found to be significant in univariate and multivariate analyses. Increased mortality was observed in patients with 2 or more risk factors, which was significantly different from patients with no risk factors or one risk factor (P < .01). None of the intra-procedure factors were important in identifying patients at risk of death. Multivariate analysis indicated post-PTBD cholangitis and unsuccessful drainage as post-procedure risk factors that correlated with in-hospital death. CONCLUSION: It was identified that in-hospital mortality was associated with 3 pre-procedure and 2 post-procedure risk factors, such as the liver function classification, quality-of-life score of cancer patients, creatinine level, PTBD-associated biliary duct infection, and unsuccessful drainage.