AIM:To evaluate the relationship between the signal intensity of hepatobiliary phase images on gadoxetic acid-enhanced magnetic resonance imaging(MRI)and histological grade.METHODS:Fifty-nine patients with 82 hepatoce...AIM:To evaluate the relationship between the signal intensity of hepatobiliary phase images on gadoxetic acid-enhanced magnetic resonance imaging(MRI)and histological grade.METHODS:Fifty-nine patients with 82 hepatocellular lesions were evaluated retrospectively.Hepatobiliary phase images on gadoxetic acid-enhanced MRI were classified into 3 groups:low,iso or high.Angiographyassisted computed tomography(CT)findings were also classified into 3 groups:CT during arterial portography,and CT hepatic arteriography:A:iso,iso or low;B:slightly low,iso or low;;and C:low,high.We correlated angiography-assisted CT,hepatobiliary phase findings during gadoxetic acid-enhanced MRI and histological grades.Furthermore,correlations between MRI findings and histological grade for each hemodynamic pattern were performed.Correlations among radiologicaland pathological findings were statistically evaluated using the chi-square test and Fisher's exact test.RESULTS:There was a significant correlation between histological grade and hemodynamic pattern(P<0.05).There was a significant correlation between histological grade and signal intensity in the hepatobiliary phase(P<0.05)in group A lesions.There was no significant correlation between histological grade and signal intensity in the hepatobiliary phase in group B or C lesions(P>0.05).CONCLUSION:Signal intensity in the hepatobiliary phase correlated with histological grade in the lesions that maintained portal blood flow,but did not correlate in lesions that showed decreased or defective portal blood flow.展开更多
Fault is a complex dynamic system controlled by the coupling of rock texture, reaction, fluid flow,stress, and rock deformation mechanism. A coupled reaction-transport- mechanical dynamic model for fault system is est...Fault is a complex dynamic system controlled by the coupling of rock texture, reaction, fluid flow,stress, and rock deformation mechanism. A coupled reaction-transport- mechanical dynamic model for fault system is established and described in this paper. An example is presented for the Shuikoushan deposit, Hunan. The results of dynamic simulation indicate that the evolution and magnitude of fracture permeability of different rocks are different, and that faulting can enhance the spatial heterogeneity of rock permeability and facilitate fluid flow and mineralization in local fault zone. The pressure for a fault usually shows a variation mode of aperiodic oscillation with time, which reflects the chaotic behavior of the evolution of a fault.展开更多
Abdominal aortic aneurysm is a common vascular disease that affects elderly population.Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm,however,endovaseular an...Abdominal aortic aneurysm is a common vascular disease that affects elderly population.Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm,however,endovaseular aneurysm repair has rapidly expanded since its first introduction in 1990s.As a less invasive technique,endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair,especially in patients with co-morbid conditions.Computed tomography （CT） angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up.2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair.CT has the disadvantage of high cummulative radiation dose,of particular concern in younger patients,since patients require regular imaging follow-ups after endovascular repair,thus,exposing patients to repeated radiation exposure for life.There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair.Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts,but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta.This article reviews the treatment options of abdominal aortic aneurysm,various image visualization tools,and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods.Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.展开更多
AIM： To compare the effect of percutaneous transhepatic portal vein embolization （PTPE） and unilateral portal vein ligation （PVL） on hepatic hemodynamics and right hepatic lobe （RHL） atrophy.METHODS： Between M...AIM： To compare the effect of percutaneous transhepatic portal vein embolization （PTPE） and unilateral portal vein ligation （PVL） on hepatic hemodynamics and right hepatic lobe （RHL） atrophy.METHODS： Between March 2005 and March 2009, 13 cases were selected for PTPE （n = 9） and PVL （n = 4） in the RHL. The PTPE group included hilar bile duct carcinoma （n = 2）, intrahepatic cholangiocarcinoma （n = 2）, hepatocellular carcinoma （n = 2） and liver metastasis （n = 3）. The PVL group included hepatocellular carcinoma （n = 2） and liver metastasis （n = 2）. In addition, observation of postoperative hepatic hemodynamics obtained from computed tomography and Doppler ultrasonography was compared between the two groups.RESULTS： Mean ages in the two groups were 58.9 ± 2.9 years （PVL group） vs 69.7 ±3.2 years （PTPE group）, which was a significant difference （P = 0.0002）. Among the indicators of liver function, including serum albumin, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, platelets and indocyanine green retention rate at 15 min, no significant differ- ences were observed between the two groups. Preop-erative RHL volumes in the PTPE and PVL groups were estimated to be 804.9 ±181.1 mL and 813.3 4±129.7 mL, respectively, with volume rates of 68.9% ± 2.8% and 69.2% ±4.2%, respectively. There were no significant differences in RHL volumes （P = 0.83） and RHL volume rates （P = 0.94）, respectively. At 1 mo after PTPE or PVL, postoperative RHL volumes in the PTPE and PVL groups were estimated to be 638.4±153.6 mL and 749.8 ± 121.9 mL, respectively, with no significant difference （P = 0.14）. Postoperative RHL volume rates in the PTPE and PVL groups were estimated to be 54.6% ± 4.2% and 63.7% ± 3.9%, respectively, which was a significant difference （P = 0.0056）. At 1 mo after the operation, the liver volume atrophy rate was 14.3% ± 2.3% in the PTPE group and 5.4%± 1.6% in the PVL group, which was a significant difference （P = 0.0061）.CONCLUSION： PTPE is a more effective procedure than PVL because PTPE is able to occlude completely the portal branch throughout the right peripheral vein.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
文摘AIM:To evaluate the relationship between the signal intensity of hepatobiliary phase images on gadoxetic acid-enhanced magnetic resonance imaging(MRI)and histological grade.METHODS:Fifty-nine patients with 82 hepatocellular lesions were evaluated retrospectively.Hepatobiliary phase images on gadoxetic acid-enhanced MRI were classified into 3 groups:low,iso or high.Angiographyassisted computed tomography(CT)findings were also classified into 3 groups:CT during arterial portography,and CT hepatic arteriography:A:iso,iso or low;B:slightly low,iso or low;;and C:low,high.We correlated angiography-assisted CT,hepatobiliary phase findings during gadoxetic acid-enhanced MRI and histological grades.Furthermore,correlations between MRI findings and histological grade for each hemodynamic pattern were performed.Correlations among radiologicaland pathological findings were statistically evaluated using the chi-square test and Fisher's exact test.RESULTS:There was a significant correlation between histological grade and hemodynamic pattern(P<0.05).There was a significant correlation between histological grade and signal intensity in the hepatobiliary phase(P<0.05)in group A lesions.There was no significant correlation between histological grade and signal intensity in the hepatobiliary phase in group B or C lesions(P>0.05).CONCLUSION:Signal intensity in the hepatobiliary phase correlated with histological grade in the lesions that maintained portal blood flow,but did not correlate in lesions that showed decreased or defective portal blood flow.
基金supported by the National Natural Science Foundation of China(Gramt No.70171057 and No.49702024)a Key Project of the Ninth Five-Year Plan of the Chinese Academof Sciences(Grant No.KZ952-S1-402).
文摘Fault is a complex dynamic system controlled by the coupling of rock texture, reaction, fluid flow,stress, and rock deformation mechanism. A coupled reaction-transport- mechanical dynamic model for fault system is established and described in this paper. An example is presented for the Shuikoushan deposit, Hunan. The results of dynamic simulation indicate that the evolution and magnitude of fracture permeability of different rocks are different, and that faulting can enhance the spatial heterogeneity of rock permeability and facilitate fluid flow and mineralization in local fault zone. The pressure for a fault usually shows a variation mode of aperiodic oscillation with time, which reflects the chaotic behavior of the evolution of a fault.
文摘Abdominal aortic aneurysm is a common vascular disease that affects elderly population.Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm,however,endovaseular aneurysm repair has rapidly expanded since its first introduction in 1990s.As a less invasive technique,endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair,especially in patients with co-morbid conditions.Computed tomography （CT） angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up.2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair.CT has the disadvantage of high cummulative radiation dose,of particular concern in younger patients,since patients require regular imaging follow-ups after endovascular repair,thus,exposing patients to repeated radiation exposure for life.There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair.Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts,but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta.This article reviews the treatment options of abdominal aortic aneurysm,various image visualization tools,and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods.Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.
文摘AIM： To compare the effect of percutaneous transhepatic portal vein embolization （PTPE） and unilateral portal vein ligation （PVL） on hepatic hemodynamics and right hepatic lobe （RHL） atrophy.METHODS： Between March 2005 and March 2009, 13 cases were selected for PTPE （n = 9） and PVL （n = 4） in the RHL. The PTPE group included hilar bile duct carcinoma （n = 2）, intrahepatic cholangiocarcinoma （n = 2）, hepatocellular carcinoma （n = 2） and liver metastasis （n = 3）. The PVL group included hepatocellular carcinoma （n = 2） and liver metastasis （n = 2）. In addition, observation of postoperative hepatic hemodynamics obtained from computed tomography and Doppler ultrasonography was compared between the two groups.RESULTS： Mean ages in the two groups were 58.9 ± 2.9 years （PVL group） vs 69.7 ±3.2 years （PTPE group）, which was a significant difference （P = 0.0002）. Among the indicators of liver function, including serum albumin, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, platelets and indocyanine green retention rate at 15 min, no significant differ- ences were observed between the two groups. Preop-erative RHL volumes in the PTPE and PVL groups were estimated to be 804.9 ±181.1 mL and 813.3 4±129.7 mL, respectively, with volume rates of 68.9% ± 2.8% and 69.2% ±4.2%, respectively. There were no significant differences in RHL volumes （P = 0.83） and RHL volume rates （P = 0.94）, respectively. At 1 mo after PTPE or PVL, postoperative RHL volumes in the PTPE and PVL groups were estimated to be 638.4±153.6 mL and 749.8 ± 121.9 mL, respectively, with no significant difference （P = 0.14）. Postoperative RHL volume rates in the PTPE and PVL groups were estimated to be 54.6% ± 4.2% and 63.7% ± 3.9%, respectively, which was a significant difference （P = 0.0056）. At 1 mo after the operation, the liver volume atrophy rate was 14.3% ± 2.3% in the PTPE group and 5.4%± 1.6% in the PVL group, which was a significant difference （P = 0.0061）.CONCLUSION： PTPE is a more effective procedure than PVL because PTPE is able to occlude completely the portal branch throughout the right peripheral vein.
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.
