AIM:To assess the usefulness of contrast-enhanced ultrasound (CEUS) during follow-up after percutaneous ablation therapy for hepatocellular carcinoma (HCC).METHODS:A total of 141 patients with HCCs who received percut...AIM:To assess the usefulness of contrast-enhanced ultrasound (CEUS) during follow-up after percutaneous ablation therapy for hepatocellular carcinoma (HCC).METHODS:A total of 141 patients with HCCs who received percutaneous ablation therapy were assessed by paired follow-up CEUS and contrast-enhanced computed tomography (CECT).The follow-up scheme was designed prospectively and the intervals between CEUS and CECT examinations were less than 14 d.Both im-ages of follow-up CEUS and CECT were reviewed by radiologists.The ablated lesions were evaluated and classified as local tumor progression (LTP) and LTPfree.LTP was defined as regrowth of tumor inside or adjacent to the successfully treated nodule.The detected new intrahepatic recurrences were also evaluated and defined as presence of intrahepatic new foci.On CEUS and CECT,LTP and new intrahepatic recurrence both were displayed as typical enhancement pattern of HCC (i.e.,hyper-enhancing during the arterial phase and washout in the late phase).With CECT as the reference standard,the ability of CEUS in detecting LTP or new intrahepatic recurrence during follow-up was evaluated.RESULTS:During a follow-up period of 1-31 mo (median,4 mo),169 paired CEUS and CECT examinations were carried out for the 141 patients.For a total of 221 ablated lesions,266 comparisons between CEUS and CECT findings were performed.Thirty-three LTPs were detected on CEUS whereas 40 LTPs were detected on CECT,there was significant difference (P < 0.001).In comparison with CECT,the numbers of false positive and false negative LTPs detected on CEUS were 6 and 13,respectively;the sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV) and overall accuracy of CEUS in detecting LTPs were 67.5%,97.4%,81.8%,94.4% and 92.3%,respectively.Meanwhile,131 new intrahepatic recurrent foci were detected on CEUS whereas 183 were detected on CECT,there was also significant difference (P < 0.05).In comparison with CECT,the numbers of false positive and false negative intrahepatic recurrences detected on CEUS were 13 and 65,respectively;the sensitivity,specificity,PPV,NPV and overall accuracy of CEUS in detecting new intrahepatic recurrent foci were 77.7%,92.0%,92.4%,76.7% and 84.0%,respectively.CONCLUSION:The sensitivity of CEUS in detecting LTP and new intrahepatic recurrence after percutaneous ablation therapy is relatively low in comparisonwith CECT.展开更多
Microwave sintering is being developed as a novel technique for the preparation of dense structural ceramics,but the mature theory has not been established due to the technical difficulties.The synchrotron radiation X...Microwave sintering is being developed as a novel technique for the preparation of dense structural ceramics,but the mature theory has not been established due to the technical difficulties.The synchrotron radiation X-ray computed tomography(SR-CT) technique was introduced for the first time into the study of microwave sintering to in-situ observe the microstructure evolution of silicon carbide(SiC) material in this paper.By applying the SR-CT technique,the reconstructed 2D and 3D images of the specimen were obtained and the double logarithm curve of mean neck size and time(Ln(x)-Ln(t)) were obtained from these reconstructed images.Various sintering phenomena including sintering neck growth during microwave treatment were observed from the reconstructed images.Furthermore,the differences in microstructure evolution and sintering kinetics between microwave and conventional sintering were analyzed based on the reconstructed images and the Ln(x)-Ln(t) curve.1) The sharp surface of grains near the contact region distinctly grew blunt and the sintering neck growth between these grains were obviously observed at the early stage.Besides,the larger particles grew faster than smaller ones.The main reason for these phenomena may be the micro-focusing effect of electric fields.2) During each of the three sintering stages,the sintering kinetics curve of double logarithm relationship between mean neck size and time shows a good linear relationship,but at the middle stage the slope of the curve increases dramatically,which is quite larger than conventional sintering.The preliminary interpretation for these extraordinary phenomena has been discussed in details.展开更多
基金Supported by Public Welfare Research Special Project from Chinese Ministry of Health,No.2008-2-10Key Project from Shanghai Health Bureau,No.20114003+2 种基金Shanghai Talent Development Project from Shanghai Human Resource and Social Security Bureau,No.2012045National Natural Science Foundation of China,No.30970837Chinese Ministry of Education,NCET-06-0723
文摘AIM:To assess the usefulness of contrast-enhanced ultrasound (CEUS) during follow-up after percutaneous ablation therapy for hepatocellular carcinoma (HCC).METHODS:A total of 141 patients with HCCs who received percutaneous ablation therapy were assessed by paired follow-up CEUS and contrast-enhanced computed tomography (CECT).The follow-up scheme was designed prospectively and the intervals between CEUS and CECT examinations were less than 14 d.Both im-ages of follow-up CEUS and CECT were reviewed by radiologists.The ablated lesions were evaluated and classified as local tumor progression (LTP) and LTPfree.LTP was defined as regrowth of tumor inside or adjacent to the successfully treated nodule.The detected new intrahepatic recurrences were also evaluated and defined as presence of intrahepatic new foci.On CEUS and CECT,LTP and new intrahepatic recurrence both were displayed as typical enhancement pattern of HCC (i.e.,hyper-enhancing during the arterial phase and washout in the late phase).With CECT as the reference standard,the ability of CEUS in detecting LTP or new intrahepatic recurrence during follow-up was evaluated.RESULTS:During a follow-up period of 1-31 mo (median,4 mo),169 paired CEUS and CECT examinations were carried out for the 141 patients.For a total of 221 ablated lesions,266 comparisons between CEUS and CECT findings were performed.Thirty-three LTPs were detected on CEUS whereas 40 LTPs were detected on CECT,there was significant difference (P < 0.001).In comparison with CECT,the numbers of false positive and false negative LTPs detected on CEUS were 6 and 13,respectively;the sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV) and overall accuracy of CEUS in detecting LTPs were 67.5%,97.4%,81.8%,94.4% and 92.3%,respectively.Meanwhile,131 new intrahepatic recurrent foci were detected on CEUS whereas 183 were detected on CECT,there was also significant difference (P < 0.05).In comparison with CECT,the numbers of false positive and false negative intrahepatic recurrences detected on CEUS were 13 and 65,respectively;the sensitivity,specificity,PPV,NPV and overall accuracy of CEUS in detecting new intrahepatic recurrent foci were 77.7%,92.0%,92.4%,76.7% and 84.0%,respectively.CONCLUSION:The sensitivity of CEUS in detecting LTP and new intrahepatic recurrence after percutaneous ablation therapy is relatively low in comparisonwith CECT.
基金supported by the National Natural Science Foundation of China (Grant Nos 10902108, 10732080, 10872190)the National Basic Research Program of China ("973" Project) (Grant No 2007CB936800)
文摘Microwave sintering is being developed as a novel technique for the preparation of dense structural ceramics,but the mature theory has not been established due to the technical difficulties.The synchrotron radiation X-ray computed tomography(SR-CT) technique was introduced for the first time into the study of microwave sintering to in-situ observe the microstructure evolution of silicon carbide(SiC) material in this paper.By applying the SR-CT technique,the reconstructed 2D and 3D images of the specimen were obtained and the double logarithm curve of mean neck size and time(Ln(x)-Ln(t)) were obtained from these reconstructed images.Various sintering phenomena including sintering neck growth during microwave treatment were observed from the reconstructed images.Furthermore,the differences in microstructure evolution and sintering kinetics between microwave and conventional sintering were analyzed based on the reconstructed images and the Ln(x)-Ln(t) curve.1) The sharp surface of grains near the contact region distinctly grew blunt and the sintering neck growth between these grains were obviously observed at the early stage.Besides,the larger particles grew faster than smaller ones.The main reason for these phenomena may be the micro-focusing effect of electric fields.2) During each of the three sintering stages,the sintering kinetics curve of double logarithm relationship between mean neck size and time shows a good linear relationship,but at the middle stage the slope of the curve increases dramatically,which is quite larger than conventional sintering.The preliminary interpretation for these extraordinary phenomena has been discussed in details.
