Clinical significance of spread of lipiodol marking for pulmonary nodules and its influence on surgery.

OBJECTIVE: Computed tomography (CT)-guided lipiodol marking is one of the targeting methods for resecting small pulmonary nodules or ground-glass nodules in video-assisted thoracic surgery (VATS). However, lipiodol spreading during marking has not been assessed, practically. In this study, we examined the clinical significance and the influence of lipiodol spreading on surgery. METHODS: From April 2010 to March 2021, 176 pulmonary nodules in 167 patients were marked with lipiodol under CT guided before VATS. The marking images after lipiodol injection were classified into "Spread" and "non-Spread." Lung resection was sequentially performed on the same day. RESULTS: All target nodules were successfully resected in VATS. In the classification of marking images, Spread was 32 (18%), non-Spread was 144 (82%). There was a significant difference in duration of surgery (mean; 138.7 min vs. 118.3 min, p = 0.0496) and amount of bleeding (mean; 32.7 g vs. 11.2 g, p = 0.0173). Provided that limited to the data of wedge resections without intrathoracic pleural adhesion (n = 117), there was no significant difference in duration of surgery (mean; 104.8 min vs. 99.6 min, p = 0.48), amount of bleeding (mean; 4.9 g vs. 5.3 g, p = 0.58). In the multivariate logistic regression analysis, the risk factor of lipiodol spreading was intrathoracic pleural adhesion (odds ratio: 3.16, 95% confidence interval: 1.12-8.97, p = 0.03). There was no relationship between marking image and complication rate. CONCLUSIONS: Lipiodol spreading did not directly influence surgery and complication. However, it was a sign of intrathoracic pleural adhesion, which could lead to increased duration of surgery and amount of bleeding.

Comparison of thrombocytopenia between patients with non-alcoholic fatty liver disease and those with hepatitis C virus-related chronic liver disease.

AIM: Thrombocytopenia is widely recognized as a simple surrogate marker of liver fibrosis in non-alcoholic fatty liver disease (NAFLD). Thrombocytopenia of NAFLD has not been compared with that of hepatitis C virus-related chronic liver disease (CLD-C). Here, we examined whether there is any difference in the platelet counts between patients with NAFLD and CLD-C and investigated the underlying mechanisms. METHODS: A total of 760 biopsy-confirmed NAFLD and 1171 CLD-C patients were enrolled. After stratification according to the liver fibrosis stage, platelet counts between NAFLD and CLD-C patients were compared. The platelet count, spleen size, serum albumin level, serum thrombopoietin level, and immature platelet fraction (IPF) value were also compared after covariate adjustment using propensity score (PS) matching. RESULTS: The median platelet counts (×104 /µL) of NAFLD and CLD-C patients were 20.2 and 18.7 (p = 2.4 × 10-5 ) in F1; 20.0 and 14.5 (p = 2.1 × 10-12 ) in F2; 16.9 and 12.3 (p = 8.1 × 10-10 ) in F3; and 11.1 and 8.1 (p = 0.02) in F4, respectively. In the F3 group, NAFLD patients had a significantly higher platelet count and significantly smaller spleen volume than CLD-C patients. Although the serum thrombopoietin levels were comparable between NAFLD and CLD-C patients, the IPF value of NAFLD patients was significantly higher than that of CLD-C patients. CONCLUSIONS: NAFLD patients had a significantly higher platelet count than CLD-C patients following stratification according to the liver fibrosis stage. The milder hypersplenism and higher platelet production in NAFLD than CLD-C may have contributed to this difference.

[Impact of Irradiation Field Aperture Controller Settings on Patient-specific Quality Assurance].

PURPOSE: The aperture shape controller (ASC) is a tool on a radiation therapy planning system to reduce complexity by increasing the aperture size of multileaf collimator (MLC). The purposes of this study were to clarify the effect of the dose index on the treatment plan when the intensity of ASC is changed and then to clarify the effect on the verification result in the individual patient-specific quality assurance (QA) using the verification phantom. METHODS: For four types of mock structures presented at AAPM TG-119, volumetric modulated arc therapy (VMAT) treatment plans with three dose levels were set without using the ASC for each of these four types. ASC settings were changed to very low, low, moderate, high and very high for the treatment plan, and the treatment plan was recreated without changing the planning target volume (PTV) and/or OAR dose constraints. The dose index of the treatment plan was then evaluated. The plan was also transferred by the true composite method to the assessment phantom, and patient-specific QA was evaluated. RESULTS: The frequency of dose constraint deviation by changing the ASC was 3.6% (2/55). In patient-specific QA, when the ASC setting was set to moderate, the γ analysis passing rate increased by 1.5% compared to the case without the ASC. In the treatment plan with a γ analysis pass rate of 95% or less without ASC, a 2.7% increase in the γ analysis pass rate was observed by setting the ASC to moderate. CONCLUSION: We found that setting the ASC tended to improve patient-specific QA. Compared to when the ASC was not set, the evaluation result of patient-specific QA was improved without violating the dose constraints of the PTV and/or organ at risk (OAR). In particular, the improvement was notable for the case where the evaluation result of patient-specific QA was 95% or less when the ASC was not used.

[Effect of Relative Electron Density and Physical Density Adjustment in Patient-specific Quality Assurance Using PMMA Phantom].

PURPOSE: The purpose of this study was to improve the accuracy of dose-distribution calculations by understanding how the calculated dose varies with the change in the relative electron density replacing polymethyl methacrylate (PMMA) in patient-specific quality assurance. METHOD: We calculated the relative electron density at which dose attenuation in each dose calculation algorithm coincides with the measured value of the dose attenuation of single-field irradiation. Next, the dose change was calculated by changing the relative electron density or physical electron density for substituting PMMA for each X-ray energy and calculation algorithm. Furthermore, using clinical plans, changes in point-dose verification and dose-distribution verification that occurred when the relative electron density or physical electron density was varied were investigated. RESULTS: The dose attenuation varies depending on the dose-calculation algorithm, and the optimum value of the electron density is different for each. After the electron density optimization, the point dose verification using the 97.1% to 98.3% (3%/3 mm), 90.0% to 94.3% (2%/3 mm) and gained a dominant improvement tendency (P<0.001). CONCLUSIONS: We clarified dose change accompanying relative electron density or physical electron density change. We concluded that the accuracy of dose-distribution calculation for verification improves by replacing PMMA with optimal relative electron density or physical electron density.