Importance of the enhanced cooling system for more spherical ablation zones: Numerical simulation, ex vivo and in vivo validation.

INTRODUCTION: This study aimed to investigate the efficacy of a small-gauge microwave ablation antenna (MWA) with an enhanced cooling system (ECS) for generating more spherical ablation zones. METHODS: A comparison was made between two types of microwave ablation antennas, one with ECS and the other with a conventional cooling system (CCS). The finite element method was used to simulate in vivo ablation. Two types of antennas were used to create MWA zones for 5, 8, 10 min at 50, 60, and 80 W in ex vivo bovine livers (n = 6) and 5 min at 60 W in vivo porcine livers (n = 16). The overtreatment ratio, ablation aspect ratio, carbonization area, and other characteristcs of antennas were measured and compared using numerical simulation and gross pathologic examination. RESULTS: In numerical simulation, the ECS antenna demonstrated a lower overtreatment ratio than the CCS antenna (1.38 vs 1.43 at 50 W 5 min, 1.19 vs 1.35 at 50 W 8 min, 1.13 vs 1.32 at 50 W 10 min, 1.28 vs 1.38 at 60 W 5 min, 1.14 vs 1.32 at 60 W 8 min, 1.10 vs 1.30 at 60 W 10 min). The experiments revealed that the ECS antenna generated ablation zones with a more significant aspect ratio (0.92 ± 0.03 vs 0.72 ± 0.01 at 50 W 5 min, 0.95 ± 0.02 vs 0.70 ± 0.01 at 50 W 8 min, 0.96 ± 0.01 vs 0.71 ± 0.04 at 50 W 10 min, 0.96 ± 0.01 vs 0.73 ± 0.02 at 60 W 5 min, 0.94 ± 0.03 vs 0.71 ± 0.03 at 60 W 8 min, 0.96 ± 0.02 vs 0.69 ± 0.04 at 60 W 10 min) and a smaller carbonization area (0.00 ± 0.00 cm2 vs 0.54 ± 0.06 cm2 at 50 W 5 min, 0.13 ± 0.03 cm2 vs 0.61 ± 0.09 cm2 at 50 W 8 min, 0.23 ± 0.05 cm2 vs 0.73 ± 0.05 m2 at 50 W 10 min, 0.00 ± 0.00 cm2 vs 1.59 ± 0.41 cm2 at 60 W 5 min, 0.23 ± 0.22 cm2 vs 2.11 ± 0.63 cm2 at 60 W 8 min, 0.57 ± 0.09 cm2 vs 2.55 ± 0.51 cm2 at 60 W 10 min). Intraoperative ultrasound images revealed a hypoechoic area instead of a hyperechoic area near the antenna. Hematoxylin-eosin staining of the dissected tissue revealed a correlation between the edge of the ablation zone and that of the hypoechoic area. CONCLUSIONS: The ECS antenna can produce more spherical ablation zones with less charring and a clearer intraoperative ultrasound image of the ablation area than the CCS antenna.

Value of the three-dimensional visualization ablation planning system in ultrasound-guided percutaneous microwave ablation for malignant adrenal tumors: A clinical comparative study.

OBJECTIVE: We aimed to assess the efficacy and safety of the three-dimensional visualization ablation planning system (3DVAPS) in ultrasound-guided percutaneous microwave ablation (US-PMWA) for malignant adrenal tumors (MATs). METHODS: A retrospective analysis was conducted on a cohort of 62 unilateral MAT cases from March 2011 to November 2022. There were a total of 62 lesions, with a mean maximum diameter of 5.4 ± 2.7 cm (range, 1.4-15.7 cm). The patients were categorized into the following, based on the pre-operative planning method: 3D planning (n = 32) and 2D planning (n = 30) groups. A comparative analysis was performed on various parameters, including ablation techniques, tumor-related prognosis, and incidence of complications. This analysis encompassed indicators, such as overall survival (OS) rate and local tumor progression (LTP), among others. RESULTS: The median follow-up period was 30 months (range, 3-84 months). Notably, compared with the 2D planning group, the 3D planning group exhibited significant disparities in the number of punctures (P = 0.035) and incidence of complications (P = 0.029) and had no significant difference in the OS ( P > 0.05) but had a significantly lower LTP rate (6.2% vs. 23.3%, P = 0.033). In the 3D planning group, the sub-group with a tumor diameter of < 5 cm exhibited a significantly less number of punctures ( P = 0.039), lower input energy ( P = 0.002), and a shorter ablation time ( P = 0.001), compared with the sub-group with a tumor diameter of ≥ 5 cm, but there was no significant difference in the LTP and OS rates between the two sub-groups ( P > 0.05). CONCLUSIONS: The use of 3DVAPS in US-PMWA of MATs was advantageous, especially in lesions with a diameter of ≥ 5 cm. It can help in developing more rational surgical plans, reducing the incidence of complications, and extending the local recurrence-free survival time of patients and can add a certain value for precise treatment and expand the indications for ablation.

MRI non-rigid registration with tumor contraction correction for ablative margin assessment after microwave ablation of hepatocellular carcinomas.

Objective. This study aims to develop and assess a tumor contraction model, enhancing the precision of ablative margin (AM) evaluation after microwave ablation (MWA) treatment for hepatocellular carcinomas (HCCs).Approach. We utilize a probabilistic method called the coherent point drift algorithm to align pre-and post-ablation MRI images. Subsequently, a nonlinear regression method quantifies local tumor contraction induced by MWA, utilizing data from 47 HCC with viable ablated tumors in post-ablation MRI. After automatic non-rigid registration, correction for tumor contraction involves contracting the 3D contour of the warped tumor towards its center in all orientations.Main results. We evaluate the performance of our proposed method on 30 HCC patients who underwent MWA. The Dice similarity coefficient between the post-ablation liver and the warped pre-ablation livers is found to be 0.95 ± 0.01, with a mean corresponding distance between the corresponding landmarks measured at 3.25 ± 0.62 mm. Additionally, we conduct a comparative analysis of clinical outcomes assessed through MRI over a 3 month follow-up period, noting that the AM, as evaluated by our proposed method, accurately detects residual tumor after MWA.Significance. Our proposed method showcases a high level of accuracy in MRI liver registration and AM assessment following ablation treatment. It introduces a potentially approach for predicting incomplete ablations and gauging treatment success.

Prognostic Significance of Advanced Age in Patients with T1a Renal Cell Carcinoma Treated by Microwave Ablation: A 16-Year Experience.

BACKGROUND: Previous studies have failed to investigate the specific effects of advanced age on survival outcomes by considering the Charlson Comorbidity Index (CCI) and age permutation in patients with T1a renal cell carcinoma (T1a RCC) treated by microwave ablation (MWA). Notably, RCC guidelines recommended radiofrequency ablation (RFA) and active surveillance (AS) are both treatment options for elderly T1a RCC, but whether MWA is superior to AS in light of higher heating efficiency and larger ablation zone compared with RFA is not clear. This study aimed to investigate the specific effects of advanced age on survival outcomes of T1a RCC patients stratified by CCI score and indicate better intervention for elderly T1a RCC between MWA and AS. METHODS: This was a retrospective study. We retrospectively reviewed 237 patients with T1a RCC who had undergone MWA over the last 16 years. Data were analyzed by Cox regression and Landmark analysis. Interaction tests and propensity score matching were used to account for potential biases. We compared the overall survival (OS) and cancer-specific survival (CSS) rates of patients ≥75 years in our study with corresponding figures from 4251 counterparts undergoing AS in published articles. RESULTS: Using patients ＜75 years with a CCI ≤2 as a reference, the hazard ratio (HR) and 95% confidence interval (CI) of OS for patients＜75 years with a CCI ≥3, patients ≥75 years with a CCI ≤2, and patients ≥75 years with CCI ≥3, were 2.954 (1.139-7.663), 3.48 (1.487-8.146), and 3.357 (1.162-9.698), respectively. The adverse effect of an age ≥75 years on OS was attenuated in patients with a CCI ≥3. The attenuation lasted for 62.5 months of follow-up (P = .017). Notably, advanced age exerted a protective effect on progression-free survival (PFS) in patients with a CCI ≥3, increasing the 8-year PFS from 67.8% to 100% (P = .049). Relative to 1-, 3-, 5-, and 8-year survival data for patients aged ≥75 undergoing AS, the OS rates for 5-year follow-up were always better in MWA. However, beyond 5 years, the OS rates dropped to levels that were similar to AS. CONCLUSIONS: Advanced age exerts adverse effects and significantly protective effects on OS and PFS, respectively, in T1a RCC patients with a CCI ≥ 3. According to our study, elderly patients with T1a RCC underwent radical MWA may yield a better medium-term OS relative to AS.

Coplanarity Constrained Ultrasound Probe Calibration Based on N-Wire Phantom.

OBJECTIVE: N-wire phantom-based ultrasound probe calibration has been used widely in many freehand tracked ultrasound imaging systems. The calibration matrix is obtained by registering the coplanar point cloud in ultrasound space and non-coplanar point cloud in tracking sensor space based on the least squares method. This method is sensitive to outliers and loses the coplanar information of the fiducial points. In this article, we describe a coplanarity-constrained calibration algorithm focusing on these issues. METHODS: We verified that the out-of-plane error along the oblique wire in the N-wire phantom followed a normal distribution and used it to remove the experimental outliers and fit the plane with the Levenberg-Marquardt algorithm. Then, we projected the points to the plane along the oblique wire. Coplanarity-constrained point cloud registration was used to calculate the transformation matrix. RESULTS: Compared with the other two commonly used methods, our method had the best calibration precision and achieved 25% and 36% improvement of the mean calibration accuracy than the closed-form solution and in-plane error method respectively at depth 16. Experiments at different depths revealed that our algorithm had better performance in our setup. CONCLUSION: Our proposed coplanarity-constrained calibration algorithm achieved significant improvement in both precision and accuracy compared with existing algorithms with the same N-wire phantom. It is expected that calibration accuracy will improve when the algorithm is applied to all other N-wire phantom-based calibration procedures.

Combination therapy using microwave ablation and d-mannose-chelated iron oxide nanoparticles inhibits hepatocellular carcinoma progression.

Despite being a common therapy for hepatocellular carcinoma (HCC), insufficient thermal ablation can leave behind tumor residues that can cause recurrence. This is believed to augment M2 inflammatory macrophages that usually play a pro-tumorigenic role. To address this problem, we designed d-mannose-chelated iron oxide nanoparticles (man-IONPs) to polarize M2-like macrophages into the antitumor M1 phenotype. In vitro and in vivo experiments demonstrated that man-IONPs specifically targeted M2-like macrophages and accumulated in peri-ablation zones after macrophage infiltration was augmented under insufficient microwave ablation (MWA). The nanoparticles simultaneously induced polarization of pro-tumorigenic M2 macrophages into antitumor M1 phenotypes, enabling the transformation of the immunosuppressive microenvironment into an immunoactivating one. Post-MWA macrophage polarization exerted robust inhibitory effects on HCC progression in a well-established orthotopic liver cancer mouse model. Thus, combining thermal ablation with man-IONPs can salvage residual tumors after insufficient MWA. These results have strong potential for clinical translation.

Multiparametric liver MRI for predicting early recurrence of hepatocellular carcinoma after microwave ablation.

BACKGROUND: High early recurrence (ER) of hepatocellular carcinoma (HCC) after microwave ablation (MWA) represents a sign of aggressive behavior and severely worsens prognosis. The aim of this study was to estimate the outcome of HCC following MWA and develop a response algorithmic strategy based on multiparametric MRI and clinical variables. METHODS: In this retrospective study, we reviewed the records of 339 patients (mean age, 62 ± 12 years; 106 men) treated with percutaneous MWA for HCC between January 2014 and December 2017 that were evaluated by multiparametric MRI. These patients were randomly split into a development and an internal validation group (3:1). Logistic regression analysis was used to screen imaging features. Multivariate Cox regression analysis was then performed to determine predictors of ER (within 2 years) of MWA. The response algorithmic strategy to predict ER was developed and validated using these data sets. ER rates were also evaluated by Kaplan-Meier analysis. RESULTS: Based on logistic regression analyses, we established an image response algorithm integrating ill-defined margins, lack of capsule enhancement, pre-ablative ADC, ΔADC, and EADC to calculate recurrence scores and define the risk of ER. In a multivariate Cox regression model, the independent risk factors of ER (p < 0.05) were minimal ablative margin (MAM) (HR 0.57; 95% CI 0.35 - 0.95; p < 0.001), the recurrence score (HR: 9.25; 95% CI 4.25 - 16.56; p = 0.021), and tumor size (HR 6.21; 95% CI 1.25 - 10.82; p = 0.014). Combining MAM and tumor size, the recurrence score calculated by the response algorithmic strategy provided predictive accuracy of 93.5%, with sensitivity of 92.3% and specificity of 83.1%. Kaplan-Meier estimates of the rates of ER in the low-risk and high-risk groups were 6.8% (95% CI 4.0 - 9.6) and 30.5% (95% CI 23.6 - 37.4), respectively. CONCLUSION: A response algorithmic strategy based on multiparametric MRI and clinical variables was useful for predicting the ER of HCC after MWA.

Dynamic changes in liver volume calculated using a three-dimensional visualisation system after microwave ablation of hepatocellular carcinomas.

OBJECTIVES: To investigate the changes in liver volume and function after microwave ablation (MWA) of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: We retrospectively analysed 76 patients with 106 nodules who underwent MWA for HCCs ≤5 cm between January 2015 and September 2017. Liver and ablation volumes were calculated using a three-dimensional visualisation system on MRI. Multiple regression analysis was used to estimate the association between the ablation volume and liver volume changes. Deformable image registration (DIR) was performed to confirm the influence of liver volume changes on curative effect evaluation after ablation. RESULTS: The initial liver and tumour volumes were 1262.1 ± 259.91 cm3 (range: 864.9-1966.8) and 2.5 cm3 (interquartile range [IQR]: 1.3-8.8), respectively. Compared to the initial liver volumes, the entire live volume (ELV) increased by 10.1% ± 8.93% (range: -4.9% to 46.68%) on the 3rd day after ablation. Subsequently, it recovered to initial level at the 3rd month and maintained its level during the 1-year follow-up. The median total ablation volume was 34.9 cm3 (IQR: 20.4-65.4) on the 3rd day after ablation, which decreased by 71.2% (IQR: 57.4%-78.1%) 1 year after ablation. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (T-Bil) peaked within 3 days after MWA and recovered to normal within 1 month. The ablation volume proportion of the ELV was an independent risk factor for the increase in the ELV and AST, ALT and T-Bil levels within 3 days after ablation. When DIR was conducted to fuse ablation zone and tumour, the reshaped tumour volumes were enlarged by 40% because of the increase in ELV. CONCLUSIONS: MWA of HCCs based on the Milan criteria could induce temporary increases in ELV and RLV within 3 days after ablation, but both parameters recovered to initial levels 3 months after ablation. This indicates that MWA of early-stage HCCs would not lead to liver volume loss and could potentially protect liver function. The liver cannot be treated as an incompressible organ after ablation, and the appropriate deformation constraint should be designed for DIR to evaluate ablation margin accurately.

Halogen-Free Flame Retardant Polypropylene Fibers with Modified Intumescent Flame Retardant: Preparation, Characterization, Properties and Mode of Action.

A novel intumescent flame retardant (IFR) agent designated as Dohor-6000A has been used to prepare halogen-free flame retardant polypropylene (PP) fibers via melting spinning. Before being blended with PP resin, a surface modification of Dohor-6000A was carried out to improve its compatibility with the PP matrix. The rheological behavior of flame retardant Dohor-6000A/PP resin, the structure, morphology, mechanical properties, flammability of the Dohor-6000A/PP fibers were studied in detail, as well as the action mode of flame retardant. X-ray diffraction (XRD) showed that the addition of Dohor-6000A did not damage the crystal as well as the orientation structure of PP matrix, which was helpful to the maintenance of mechanical properties. The presence of the IFR significantly improved the flame retardant performance and thermal stability of PP fibers. When the content of Dohor-6000A reached 25%, the fibers displayed a limiting oxygen index (LOI) value of 29.1% and good melt-drop resistance. Moreover, the peak heat release rate (PHRR) and total heat release (THR) from microscale combustion colorimetry (MCC) tests were decreased by 26.0% and 16.0% in comparison with the same conditions for pure PP fibers. In the condensed phase, the IFR promoted a carbonization process and promoted the formation of a glassy or stable foam protective layer on the surface of the polymer matrix. In addition, the IFR decomposed endothermically to release of non-combustible gases such as NH3 and CO2 which dilutes the combustible gases in the combustion zone.

3D visualization ablation planning system assisted microwave ablation for hepatocellular carcinoma (Diameter >3): a precise clinical application.

BACKGROUND: The aim of this retrospective study was to compare the feasibility and efficiency of ultrasound-guided percutaneous microwave ablation (US-PMWA) assisted by three-dimensional visualization ablation planning system (3DVAPS) and conventional 2D planning for hepatocellular carcinoma (HCC) (diameter > 3 cm). METHODS: One hundred thirty patients with 223 HCC nodules (5.0 ± 1.5 cm in diameter, [3.0-10.0 cm]) who met the eligibility criteria divided into 3D and 2D planning group were reviewed from April 2015 to August 2018. Ablation parameters and oncological outcomes were compared, including overall survival (OS), recurrence-free survival (RFS), and local tumor progression (LTP). Multivariate analysis was performed on clinicopathological variables to identify the risk factors for OS and LTP. RESULTS: The median follow-up period was 21 months (range 3-44). Insertion number (5.4 ± 1.2 VS. 4.5 ± 0.9, P = 0.034), ablation time (1249.2 ± 654.2 s VS. 1082.4 ± 584.7 s, P = 0.048), ablation energy (57,000 ± 11,892 J VS. 42,600 ± 10,271 J, P = 0.038) and success rate of first ablation (95.0% VS. 85.7%, P = 0.033) were higher in the 3D planning group compared with those in 2D planning group. There was no statistical difference in OS, and RFS between the two groups (P = 0.995, P = 0.845). LTP rate of 3D planning group was less than that of 2D planning group (16.5% VS 41.2%, P = 0.003). Multivariate analysis showed tumor maximal diameters (P < 0.001), tumor number (P = 0.003) and preoperative TACE (P < 0.001) were predictors for OS and sessions (P = 0.024), a-fetoprotein level (P = 0.004), and preoperative planning (P = 0.002) were predictors for LTP, respectively. CONCLUSIONS: 3DVAPS improves precision of US guided ablation resulting in lower LTP and higher 5 mm-AM for patients with HCC lesions larger than 3 cm in diameter.

The value of 3D visualization operative planning system in ultrasound-guided percutaneous microwave ablation for large hepatic hemangiomas: a clinical comparative study.

BACKGROUND: To evaluate the value of a three dimension (3D)visualization operative planning system in ultrasound-guided percutaneous microwave ablation (US-PMWA) for large hepatic hemangiomas (LHHs). METHODS: Fifty-eight patients with LHHs were divided into 3D and 2D groups. The therapeutic efficacy was assessed by contrast-enhanced imaging during follow-up. Hepatic and renal function were examined. The complete ablation, tumor volume shrinkage, and complication rates were analyzed. RESULTS: The ablation time and energy of the 3D group were lower than those of the 2D group (1152.0 ± 403.9 s vs. 1379.7 ± 375.8 s and 87,407.2.9 ± 50,387.0 J vs. 117,775.8 ± 46,245.6 J, P = 0.031 and 0.021, respectively). The 3D group had a higher complete ablation rate than the 2D group (97.7 ± 2.4% vs. 94.5 ± 3.7%, P < 0.001). The incidence of hemoglobinuria after ablation in the 3D group was lower than that in the 2D group (32.0% vs. 57.6%, P = 0.047). The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and creatinine (Cre) after ablation in the 3D group were lower than those in the 2D group (126.7 ± 56.4 U/L vs. 210.9 ± 96.2 U/L, P < 0.001; 141.0 ± 60.8 U/L vs. 211.4 ± 90.0 U/L, P = 0.001; 57.3 ± 17.6 U/L vs. 80.8 ± 41.9 U/L, P = 0.010; and 66.6 ± 16.6 mmol/L vs. 84.5 ± 39.6 mmol/L, P = 0.037, respectively). There were no significant differences in antenna insertion and the volume reduction rate between the groups. One patient developed acute kidney injury shortly after ablation in the 2D group and recovered after hemodialysis. No other severe complications occurred during the follow-up period. CONCLUSIONS: The 3D visualization operative planning system has a relatively high clinical application value in providing scientific, reasonable, quantifiable, and individualized therapy for LHHs by US-PMWA.

Microwave ablation assisted by three-dimensional visualization system as local therapy for relapsed hepatoblastoma: a small pilot study.

PURPOSE: We aimed to explore the feasibility of microwave ablation (MWA) assisted by three-dimensional visualization system for relapsed HB in children. METHODS: From August 2014 to February 2017, five patients with relapsed HB were enrolled. A total of 12 liver tumors were treated with MWA assisted by a three-dimensional visualization system. Follow-up data were obtained in all patients. The residual liver volume, local tumor progression, new intrahepatic tumors, survival outcome, and complications were analyzed. RESULTS: All tumors were completely ablated in a single session. The mean ablation time per tumor was 9.7 ± 8.6 min, and the median ablation/liver volume ratio was 2.37%. No local tumor progression was observed during a follow-up period of 9-39 months. All patients were still alive at the end of the follow-up. The median progression-free survival time after ablation was 9 months, and the median survival time after ablation was 12 months. No other complications were observed except for fever. CONCLUSIONS: MWA assisted by three-dimensional visualization system appears to be a safe and feasible local treatment for recurrent HB in pediatric patients.

Comparison of parallel and crossed placement of antennas in microwave ablation of 3-5 cm hepatocellular carcinoma.

PURPOSE: To evaluate the effects of ablation strategies on local tumor progression (LTP) after microwave ablation (MWA) of hepatocellular carcinomas (HCCs) measuring 3-5 cm. MATERIALS AND METHODS: Between December 2011 and May 2017, 71 HCC patients with 71 nodules treated by ultrasound(US)-guided percutaneous MWA were divided into parallel (group A) and crossed (group B) antenna placement groups. All patients underwent MWA using two antennas with four insertions. LTP and overall survival (OS) rates were compared between the two groups. RESULTS: The median follow-up time was 16.8 months. There was no significant difference in the complete ablation rate and treatment sessions between the two groups. LTP was diagnosed in 8 of 48 nodules (16.7%) in group A and 1 of 23 nodules (4.3%) in group B, with no significant difference between two groups (P = 0.115). The 1-, 2-, and 3-year OS rates were 88.5%, 79%, and 71.8% in group A and 93.8%, 87.5%, and 87.5% in group B, respectively (P = 0.236). Multivariate analysis showed that the tumor diameter (P = 0.017), the distance between the antennas (P = 0.032), and the total emission time (P = 0.015) were associated with LTP. CONCLUSIONS: There were trends with lower LTP and improved OS in group B, despite the lack of statistically significant differences between the two strategies at a level of P < 0.05. The increase of distance between antennas and total emission time will facilitate reductions in LTP rate.

A tumor map generated from three-dimensional visualization of image fusion for the assessment of microwave ablation of hepatocellular carcinoma: a preliminary study.

PURPOSE: This study aimed to investigate the clinical value of a tumor map for assessing the ablative effect after ultrasound-guided percutaneous microwave ablation (US-PMWA) for hepatocellular carcinoma (HCC). METHODS: The medical records of 68 patients (49 male and 19 female, 59.9±12.7 years) with HCC who underwent US-PMWA from May 2013 to May 2017 were reviewed. A tumor map was generated from the fusion of three-dimensional (3D) visualization images based on the preoperative target tumor and postoperative ablation area, to evaluate whether the ablation area covering the tumor has reached a 5 mm ablative margin (AM). The lesions were divided into two groups according to the tumor maps: group A (failed to achieve AM) and group B (achieved AM). The cumulative local tumor progression (LTP) rates of both groups were statistically analyzed using the log-rank test. RESULTS: Success rate of tumor map generation was 100% (68/68), and no residual tumors were found. MWA-related 3D images, which included target tumor volume, ablation area volume, and residual liver ratio, were compared between groups A and B (P=0.295, P=0.772, and P=0.527, respectively). Technique effectiveness rate (91.7% vs 100%) was achieved in the two groups, showing no significant statistical differences (P=0.672). The 3-, 6-, 9-, and 12-month LTP rate was 8.3%, 16.7%, 20.8%, and 34%, respectively, for group A and 0%, 2.8%, 2.8%, and 2.8%, respectively, for group B, showing significant statistical differences (P<0.001) between the two groups. CONCLUSION: The novel technology of tumor map generated from 3D visualization of image fusion is feasible and useful in evaluating the ablative effect of US-PMWA for HCC.

Structure and properties of halogen-free flame retardant and phosphorus-containing aromatic poly(1,3,4-oxadiazole)s fiber.

In order to improve the flame retardance of aromatic polyoxadiazole (p-POD) fiber, a series of phosphorus-containing PODs (pho-POD) were synthesized by introducing triaryl phosphine oxide (TPO) units into the main chains of p-POD using hydrazine sulfate, terephthalic acid and bis(p-carboxy)phenyl phosphine oxide (BCPPO) as monomers, and then halogen-free flame resistant pho-POD fibers were obtained from wet spinning. The structure and properties of the pho-POD fibers were characterized and measured in detail using the methods of wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), the limiting oxygen index (LOI), oxygen bomb calorimeter, Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) etc. The results show that the introduction of TPO units resulted in the weakening of the crystallization ability, the formation of the poriferous and lax interior structure, the slight decrease in the thermal stability and mechanical properties of the POD fibers. However, the value of LOI obviously increased from 28% to 35%, and the gross heat of combustion (GHC) decreased from 19.72 MJ kg-1 to 17.84 MJ kg-1 with the increase in the content of the BCPPO. Moreover, the combustion residue of pho-POD fiber revealed a smooth, dense and non-porous carbon layer, which could effectively play a role of oxygen barrier and enhance the flame resistance. From the above results, it can be concluded that the flame resistance of the POD fiber could be improved significantly after introducing the TPO unit. The results of Py-GC/MS illustrate that the TPO unit of pho-POD could inhibit the production of volatile products, which could be confirmed that the mechanism of enhancing the flame retardancy by introducing TPO units was mainly the flame retardation of the condensed phase.

Ultrasound-guided percutaneous microwave ablation assisted by athree-dimensional visualization treatment platform combined with transcatheter arterial chemoembolization for a single large hepatocellular carcinoma 5 cm or larger: a preliminary clinical application.

Objective: To assess the clinical efficiency and feasibility of ultrasound-guided percutaneous microwave ablation (US-PMWA) assisted by a three-dimensional (3D) visualization platform for treating a single large hepatocellular carcinoma (HCC) (diameter ≥5 cm).Methods: We included 40 patients with a single large HCC from May 2015 to August 2017. Nineteen patients who underwent US-PMWA assisted by a 3D visualization platform formed the 3D group; 21 patients without 3D visualization assistance formed the control group. Preoperative planning and post-procedural evaluation were performed successfully with the 3D visualization treatment platform. Thermal ablative parameters, survival and recurrence were compared between groups.Results: The primary efficacy rate and recurrence-free survival (RFS) rate in the 3D group were higher than those in the control group (p = .007 and p = .014, respectively). The number of inserted probes in the 3D group was higher than that in the control group (p = .016). The overall survival (OS) rate in the 3D group was comparable to that of controls (p = .745). Estimated 3-year OS and RFS rates were 38.5% and 64.6% in the 3D group and 34.4% and 18.8% in the control group, respectively. Treatment effects were evaluated using a tumor map and confirmed by traditional contrast-enhanced ultrasound in the 3D group. After the first treatment, nine patients (47.4%) achieved complete ablation with a 5-mm safety margin. No major complications related to ablation occurred.Conclusions: US-PMWA assisted by a 3D visualization treatment platform can improve treatment efficiency and appears to be a safe, effective and innovative technique to manage a single large HCC.

Quantitative assessment of murine articular cartilage and bone using X-ray phase-contrast imaging.

Murine models for rheumatoid arthritis (RA) research can provide important insights for understanding RA pathogenesis and evaluating the efficacy of novel treatments. However, simultaneously imaging both murine articular cartilage and subchondral bone using conventional techniques is challenging because of low spatial resolution and poor soft tissue contrast. X-ray phase-contrast imaging (XPCI) is a new technique that offers high spatial resolution for the visualisation of cartilage and skeletal tissues. The purpose of this study was to utilise XPCI to observe articular cartilage and subchondral bone in a collagen-induced arthritis (CIA) murine model and quantitatively assess changes in the joint microstructure. XPCI was performed on the two treatment groups (the control group and CIA group, n = 9 per group) to monitor the progression of damage to the femur from the knee joint in a longitudinal study (at 0, 4 and 8 weeks after primary injection). For quantitative assessment, morphologic parameters were measured in three-dimensional (3D) images using appropriate image analysis software. Our results showed that the average femoral cartilage volume, surface area and thickness were significantly decreased (P<0.05) in the CIA group compared to the control group. Meanwhile, these decreases were accompanied by obvious destruction of the surface of subchondral bone and a loss of trabecular bone in the CIA group. This study confirms that XPCI technology has the ability to qualitatively and quantitatively evaluate microstructural changes in mouse joints. This technique has the potential to become a routine analysis method for accurately monitoring joint damage and comprehensively assessing treatment efficacy.

Geometric correction method for 3D in-line X-ray phase contrast image reconstruction.

BACKGROUND: Mechanical system with imperfect or misalignment of X-ray phase contrast imaging (XPCI) components causes projection data misplaced, and thus result in the reconstructed slice images of computed tomography (CT) blurred or with edge artifacts. So the features of biological microstructures to be investigated are destroyed unexpectedly, and the spatial resolution of XPCI image is decreased. It makes data correction an essential pre-processing step for CT reconstruction of XPCI. METHODS: To remove unexpected blurs and edge artifacts, a mathematics model for in-line XPCI is built by considering primary geometric parameters which include a rotation angle and a shift variant in this paper. Optimal geometric parameters are achieved by finding the solution of a maximization problem. And an iterative approach is employed to solve the maximization problem by using a two-step scheme which includes performing a composite geometric transformation and then following a linear regression process. After applying the geometric transformation with optimal parameters to projection data, standard filtered back-projection algorithm is used to reconstruct CT slice images. RESULTS: Numerical experiments were carried out on both synthetic and real in-line XPCI datasets. Experimental results demonstrate that the proposed method improves CT image quality by removing both blurring and edge artifacts at the same time compared to existing correction methods. CONCLUSIONS: The method proposed in this paper provides an effective projection data correction scheme and significantly improves the image quality by removing both blurring and edge artifacts at the same time for in-line XPCI. It is easy to implement and can also be extended to other XPCI techniques.

Emphysema early diagnosis using X-ray diffraction enhanced imaging at synchrotron light source.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide, and emphysema is a common component of COPD. Currently, it is very difficult to detect early stage emphysema using conventional radiographic imaging without contrast agents, because the change in X-ray attenuation is not detectable with absorption-based radiography. Compared with the absorption-based CT, phase contrast imaging has more advantages in soft tissue imaging, because of its high spatial resolution and contrast. METHODS: In this article, we used diffraction enhanced imaging (DEI) method to get the images of early stage emphysematous and healthy samples, then extract X-ray absorption, refraction, and ultra-small-angle X-ray scattering (USAXS) information from DEI images using multiple image radiography (MIR). We combined the absorption image with the USAXS image by a scatter plot. The critical threshold in the scatter plot was calibrated using the linear discriminant function in the pattern recognition. RESULTS: USAXS image was sensitive to the change of tissue micro-structure, it could show the lesions which were invisible in the absorption image. Combined with the absorption-based image, the USAXS information enabled better discrimination between healthy and emphysematous lung tissue in a mouse model. The false-color images demonstrated that our method was capable of classifying healthy and emphysematous tissues. CONCLUSION: Here we present USAXS images of early stage emphysematous and healthy samples, where the dependence of the USAXS signal on micro-structures of biomedical samples leads to improved diagnosis of emphysema in lung radiographs.