To date the imaging diagnosis of liver lesions is based mainly on the identification of vascular features, which are typical of overt hepatocellular carcinoma(HCC), but the hepatocarcinogenesis is a complex and multis...To date the imaging diagnosis of liver lesions is based mainly on the identification of vascular features, which are typical of overt hepatocellular carcinoma(HCC), but the hepatocarcinogenesis is a complex and multistep event during which, a spectrum of nodules develop within the liver parenchyma, including benign small and large regenerative nodule(RN), low-grade dysplastic nodule(LGDN), high-grade dysplastic nodule(HGDN), early HCC, and well differentiated HCC. These nodules may be characterised not only on the basis of their respective different blood supplies, but also on their different hepatocyte function. Recently, in liver imaging the introduction of hepatobiliary magnetic resonance imaging contrast agent offered the clinicians the possibility to obtain, at once, information not only related to the vascular changes of liver nodules but also information on hepatocyte function. For this reasons this new approach becomes the most relevant diagnostic clue for differentiating low-risk nodules(LGDN-RN) from highrisk nodules(HGDN/early HCC or overt HCC) and consequently new diagnostic algorithms for HCC have been proposed. The use of hepatobiliary contrast agents is constantly increasing and gradually changing the standard of diagnosis of HCC. The main purpose of this review is to underline the added value of Gd-EOB-DTPA in early-stage diagnoses of HCC. We also analyse the guidelines for the diagnosis and management of HCC, the key concepts of HCC development, growth and spread and the imaging appearance of precursor nodules that eventually may transform into overt HCC.展开更多
AIM： To evaluate the contrast-enhanced endosonography as a method of differentiating inflammation from pancreatic carcinoma based on perfusion characteristics of microvessels. METHODS： In 86 patients with suspected ...AIM： To evaluate the contrast-enhanced endosonography as a method of differentiating inflammation from pancreatic carcinoma based on perfusion characteristics of microvessels. METHODS： In 86 patients with suspected chronic pancreatitis （age： 62± 12 years; sex： f/m 38/48）, pancreatic lesions were examined by conventional endo- scopic B-mode, power Doppler ultrasound and contrastenhanced power mode （Hitachi EUB 525, SonoVue, 2.4 mL, Bracco） using the following criteria for malignant lesions： no detectable vascularisation using conventional power Doppler scanning, irregular appearance of arterial vessels over a short distance using SonoVue contrastenhanced technique and no detectable venous vessels inside the lesion. A malignant lesion was assumed if all criteria were detectable [gold standard endoscopic ultrasound （EUS）-guided fine needle aspiration cytology, operation]. The criteria of chronic pancreatitis without neoplasia were defined as no detectable vascularisation before injection of SonoVue, regular appearance of vessels over a distance of at least 20 mm after injection of SonoVue and detection of arterial and venous vessels. RESULTS： The sensitivity and specifidty of conventional EUS were 73.2% and 83.3% respectively for pancreatic cancer. The sensitivity of contrast-enhanced EUS increased to 91.1% in 51 of 56 patients with malignant pancreatic lesion and the specificity increased to 93.3% in 28 of 30 patients with chronic inflammatory pancreatic disease.CONCLUSION： Contrast-enhanced endoscopic ultrasound improves the differentiation between chronic pancreatitis and pancreatic carcinoma.展开更多
The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the vari...The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia. The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However, the opposite interdecadal variation was found in the rainfall anomaly in North China and South China. The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean, which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation.展开更多
There have been continuous efforts to seek novel functional two-dimensional semiconductors with high performance for future applications in nanoelectronics and optoelectronics. In this work, we introduce a successful ...There have been continuous efforts to seek novel functional two-dimensional semiconductors with high performance for future applications in nanoelectronics and optoelectronics. In this work, we introduce a successful experimental approach to fabricate monolayer phosphorene by mechanical cleavage and a subsequent Ar＊ plasma thinning process. The thickness of phosphorene is unambiguously determined by optical contrast spectra combined with atomic force microscopy （AFM）. Raman spectroscopy is used to characterize the pristine and plasma-treated samples. The Raman frequency of the A2g mode stiffens, and the intensity ratio of A2g to Alg modes shows a monotonic discrete increase with the decrease of phosphorene thickness down to a monolayer. All those phenomena can be used to identify the thickness of this novel two-dimensional semiconductor. This work on monolayer phosphorene fabrication and thickness determination will facilitate future research on phosphorene.展开更多
Background Renal clear cell carcinoma （RCCC） is the most common malignant renal tumor. It is highly malignant, does not cause clinical symptoms in its early stages, and cannot be diagnosed using conventional ultraso...Background Renal clear cell carcinoma （RCCC） is the most common malignant renal tumor. It is highly malignant, does not cause clinical symptoms in its early stages, and cannot be diagnosed using conventional ultrasound. This study was aimed to investigate the contrast-enhanced ultrasound （CEUS） mode and characteristics of the time-intensity curve for RCCC and its pathological basis. Methods Forty-two patients with pathologically diagnosed RCCC underwent CEUS examination before surgery. The patients＇ kidneys were visualized after injection of contrast agents using the Technos MPX DU8. We analyzed the CEUS mode, time-intensity curve, and pathological findings. Results The detection rate of RCCC with conventional ultrasound was about 71%, while the rate using CEUS was 100%. Larger tumors （33 cases） showed non-uniform enhancement with defective filling. CEUS modes were divided into 4 types： type Ⅰ, ＂quick in and out＂ （26.19%, 11/42）; type Ⅱ, ＂quick in and slow out＂ （40.48%, 17/42）; type Ⅲ, ＂Simultaneous in and out＂ （16.67%, 7/42）; and type Ⅳ ＂slow in and out＂ （16.67%, 7/42）. All types had a close correlation to the pathological basis. Time-intensity curve of CEUS consisted of 3 phases, the perfusion phase, regression phase, and lag phase. Cases of types Ⅰ and Ⅲ only had a perfusion and regression phase, those of type Ⅱ and Ⅳ had a perfusion phase, regression phase, and lag phase. Quantitative analysis of the time-intensity curve showed that the time-to-peak （FTP） of the lesions was shorter than that of normal renal parenchyma （P 〈0.0001）, the mean value of the up slope rate of the absolute value of lesions was higher than that of the ipsilateral normal renal parenchyma （P 〈0.0001）, and that the mean value of descent slope rate of the absolute value of lesions was lower than that of the ipsilateral normal renal parenchyma （P 〈0.0001）. Conclusions CEUS is useful in detecting small vessels in tumors. Although there are several differen展开更多
Background Endometrial carcinoma is one of the most common gynecological malignancies among women.Early diagnosis and correct preoperative evaluation of myometrial invasion are necessary to improve the prognosis.This ...Background Endometrial carcinoma is one of the most common gynecological malignancies among women.Early diagnosis and correct preoperative evaluation of myometrial invasion are necessary to improve the prognosis.This study aimed to determine whether features and time-intensity curves （TIC） of transvaginal contrast-enhanced ultrasound （CEUS） differ from those of conventional ultrasound for endometrial carcinoma,and to further explore the clinical role of transvaginal CEUS in the early diagnosis of endometrial carcinoma.Methods Forty women with a normal uterus and seventy-nine patients with endometrial carcinoma were examinedby the transvaginal CEUS with SonoVue （Bracco,Imaging B.V,Switzerland）.The enhancement patterns and TIC of lesions were analyzed.The results of CEUS were compared with those of conventional ultrasound and pathology.Results In the early and late enhanced stages,the intensity of enhancement of the normal endometrium was always lower than that in the myometrium,and the boundary between normal endometrium and myometrium was clear.A total of 65.8% （52/79） of lesions presented with inhomogeneous enhancement,34.2% （27/79） presented with homogeneous enhancement; 60.8% （48/79） presented with hyperechoic enhancement,27.8% （22/79） presented with isoechoic enhancement,and 11.4% （9/79） presented with hypoechoic enhancement.The average arrival time,time to peak,rise time,half-wash out time of lesions were shorter than of normal endometrium （P 〈0.05）.The average peak intensity,relative rise in intensity,half-wash out intensity of lesions were higher than of normal endometrium （P〈0.05）.There were 49 （must be and may be present） cases of endometrial carcinoma by ultrasound （US）; 24 cases were consistent with pathology results,16 cases were underestimated and 9 cases were overestimated.There were 72 （must be and may be present） cases of endometrial carcinoma by CEUS; 53 cases were consistent with pathology results,12 cases were underestimated and 7 cases we展开更多
Contrast-enhanced ultrasound(CEUS)using microbubble contrast agents are useful for the diagnosis of the nodules in liver cirrhosis.CEUS can be used as a problem-solving method for indeterminate nodules on computed tom...Contrast-enhanced ultrasound(CEUS)using microbubble contrast agents are useful for the diagnosis of the nodules in liver cirrhosis.CEUS can be used as a problem-solving method for indeterminate nodules on computed tomography(CT)or magnetic resonance imaging(MRI)or as an initial diagnostic test for small newly detected liver nodules.CEUS has unique advantages over CT and MRI including no renal excretion of contrast,real-time imaging capability,and purely intravascular contrast.Hepatocellular carcinoma(HCC)is characterized by arterial-phase hypervascularity and later washout(negative enhancement).Benign nodules such as regenerative nodules or dysplastic nodules are usually isoechoic or slightly hypoechoic in the arterial phase and isoechoic in the late phase.However,there are occasional HCC lesions with atypical enhancement including hypovascular HCC and hypervascular HCC without washout.Cholangiocarcinomas are infrequently detected during HCC surveillance and mostly show rimlike or diffuse hypervascularity followed by rapid washout.Hemangiomas are often found at HCC surveillance and are easily diagnosed by CEUS.CEUS can be effectively used in the diagnostic work-up of small nodules detected at HCC surveillance.CEUS is also useful to differentiate malignant and benign venous thrombosis and to guide and monitor the local ablation therapy for HCC.展开更多
文摘To date the imaging diagnosis of liver lesions is based mainly on the identification of vascular features, which are typical of overt hepatocellular carcinoma(HCC), but the hepatocarcinogenesis is a complex and multistep event during which, a spectrum of nodules develop within the liver parenchyma, including benign small and large regenerative nodule(RN), low-grade dysplastic nodule(LGDN), high-grade dysplastic nodule(HGDN), early HCC, and well differentiated HCC. These nodules may be characterised not only on the basis of their respective different blood supplies, but also on their different hepatocyte function. Recently, in liver imaging the introduction of hepatobiliary magnetic resonance imaging contrast agent offered the clinicians the possibility to obtain, at once, information not only related to the vascular changes of liver nodules but also information on hepatocyte function. For this reasons this new approach becomes the most relevant diagnostic clue for differentiating low-risk nodules(LGDN-RN) from highrisk nodules(HGDN/early HCC or overt HCC) and consequently new diagnostic algorithms for HCC have been proposed. The use of hepatobiliary contrast agents is constantly increasing and gradually changing the standard of diagnosis of HCC. The main purpose of this review is to underline the added value of Gd-EOB-DTPA in early-stage diagnoses of HCC. We also analyse the guidelines for the diagnosis and management of HCC, the key concepts of HCC development, growth and spread and the imaging appearance of precursor nodules that eventually may transform into overt HCC.
文摘AIM： To evaluate the contrast-enhanced endosonography as a method of differentiating inflammation from pancreatic carcinoma based on perfusion characteristics of microvessels. METHODS： In 86 patients with suspected chronic pancreatitis （age： 62± 12 years; sex： f/m 38/48）, pancreatic lesions were examined by conventional endo- scopic B-mode, power Doppler ultrasound and contrastenhanced power mode （Hitachi EUB 525, SonoVue, 2.4 mL, Bracco） using the following criteria for malignant lesions： no detectable vascularisation using conventional power Doppler scanning, irregular appearance of arterial vessels over a short distance using SonoVue contrastenhanced technique and no detectable venous vessels inside the lesion. A malignant lesion was assumed if all criteria were detectable [gold standard endoscopic ultrasound （EUS）-guided fine needle aspiration cytology, operation]. The criteria of chronic pancreatitis without neoplasia were defined as no detectable vascularisation before injection of SonoVue, regular appearance of vessels over a distance of at least 20 mm after injection of SonoVue and detection of arterial and venous vessels. RESULTS： The sensitivity and specifidty of conventional EUS were 73.2% and 83.3% respectively for pancreatic cancer. The sensitivity of contrast-enhanced EUS increased to 91.1% in 51 of 56 patients with malignant pancreatic lesion and the specificity increased to 93.3% in 28 of 30 patients with chronic inflammatory pancreatic disease.CONCLUSION： Contrast-enhanced endoscopic ultrasound improves the differentiation between chronic pancreatitis and pancreatic carcinoma.
基金This research was supported by the National Natural Science Foundation of China un-der Grant No.40233033.
文摘The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia. The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However, the opposite interdecadal variation was found in the rainfall anomaly in North China and South China. The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean, which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation.
基金Acknowledgements The authors would like to thank Prof. Wei Ji from Renmin University for his kindness in sharing with us the unpublished results on the electronic structure calculations of black phosphorus, Prof. Pingheng Tan for his guidance on early Raman characterization, and Dr. Shuo Ding on her assistance with obtaining the optical image used in TOC. This work is financially supported by the National Natural Science Foundation of China （Nos. 51222202, 11104026, and 61376104）, the National Basic Research Program of China （No. 2014CB932500） and the Program for Innovative Research Teams in Universities of the Ministry of Education of China （No. IRT13037） and the Fundamental Research Funds for the Central Universities （No. 2014XZZX003-07）.
文摘There have been continuous efforts to seek novel functional two-dimensional semiconductors with high performance for future applications in nanoelectronics and optoelectronics. In this work, we introduce a successful experimental approach to fabricate monolayer phosphorene by mechanical cleavage and a subsequent Ar＊ plasma thinning process. The thickness of phosphorene is unambiguously determined by optical contrast spectra combined with atomic force microscopy （AFM）. Raman spectroscopy is used to characterize the pristine and plasma-treated samples. The Raman frequency of the A2g mode stiffens, and the intensity ratio of A2g to Alg modes shows a monotonic discrete increase with the decrease of phosphorene thickness down to a monolayer. All those phenomena can be used to identify the thickness of this novel two-dimensional semiconductor. This work on monolayer phosphorene fabrication and thickness determination will facilitate future research on phosphorene.
文摘Background Renal clear cell carcinoma （RCCC） is the most common malignant renal tumor. It is highly malignant, does not cause clinical symptoms in its early stages, and cannot be diagnosed using conventional ultrasound. This study was aimed to investigate the contrast-enhanced ultrasound （CEUS） mode and characteristics of the time-intensity curve for RCCC and its pathological basis. Methods Forty-two patients with pathologically diagnosed RCCC underwent CEUS examination before surgery. The patients＇ kidneys were visualized after injection of contrast agents using the Technos MPX DU8. We analyzed the CEUS mode, time-intensity curve, and pathological findings. Results The detection rate of RCCC with conventional ultrasound was about 71%, while the rate using CEUS was 100%. Larger tumors （33 cases） showed non-uniform enhancement with defective filling. CEUS modes were divided into 4 types： type Ⅰ, ＂quick in and out＂ （26.19%, 11/42）; type Ⅱ, ＂quick in and slow out＂ （40.48%, 17/42）; type Ⅲ, ＂Simultaneous in and out＂ （16.67%, 7/42）; and type Ⅳ ＂slow in and out＂ （16.67%, 7/42）. All types had a close correlation to the pathological basis. Time-intensity curve of CEUS consisted of 3 phases, the perfusion phase, regression phase, and lag phase. Cases of types Ⅰ and Ⅲ only had a perfusion and regression phase, those of type Ⅱ and Ⅳ had a perfusion phase, regression phase, and lag phase. Quantitative analysis of the time-intensity curve showed that the time-to-peak （FTP） of the lesions was shorter than that of normal renal parenchyma （P 〈0.0001）, the mean value of the up slope rate of the absolute value of lesions was higher than that of the ipsilateral normal renal parenchyma （P 〈0.0001）, and that the mean value of descent slope rate of the absolute value of lesions was lower than that of the ipsilateral normal renal parenchyma （P 〈0.0001）. Conclusions CEUS is useful in detecting small vessels in tumors. Although there are several differen
文摘Background Endometrial carcinoma is one of the most common gynecological malignancies among women.Early diagnosis and correct preoperative evaluation of myometrial invasion are necessary to improve the prognosis.This study aimed to determine whether features and time-intensity curves （TIC） of transvaginal contrast-enhanced ultrasound （CEUS） differ from those of conventional ultrasound for endometrial carcinoma,and to further explore the clinical role of transvaginal CEUS in the early diagnosis of endometrial carcinoma.Methods Forty women with a normal uterus and seventy-nine patients with endometrial carcinoma were examinedby the transvaginal CEUS with SonoVue （Bracco,Imaging B.V,Switzerland）.The enhancement patterns and TIC of lesions were analyzed.The results of CEUS were compared with those of conventional ultrasound and pathology.Results In the early and late enhanced stages,the intensity of enhancement of the normal endometrium was always lower than that in the myometrium,and the boundary between normal endometrium and myometrium was clear.A total of 65.8% （52/79） of lesions presented with inhomogeneous enhancement,34.2% （27/79） presented with homogeneous enhancement; 60.8% （48/79） presented with hyperechoic enhancement,27.8% （22/79） presented with isoechoic enhancement,and 11.4% （9/79） presented with hypoechoic enhancement.The average arrival time,time to peak,rise time,half-wash out time of lesions were shorter than of normal endometrium （P 〈0.05）.The average peak intensity,relative rise in intensity,half-wash out intensity of lesions were higher than of normal endometrium （P〈0.05）.There were 49 （must be and may be present） cases of endometrial carcinoma by ultrasound （US）; 24 cases were consistent with pathology results,16 cases were underestimated and 9 cases were overestimated.There were 72 （must be and may be present） cases of endometrial carcinoma by CEUS; 53 cases were consistent with pathology results,12 cases were underestimated and 7 cases we
文摘Contrast-enhanced ultrasound(CEUS)using microbubble contrast agents are useful for the diagnosis of the nodules in liver cirrhosis.CEUS can be used as a problem-solving method for indeterminate nodules on computed tomography(CT)or magnetic resonance imaging(MRI)or as an initial diagnostic test for small newly detected liver nodules.CEUS has unique advantages over CT and MRI including no renal excretion of contrast,real-time imaging capability,and purely intravascular contrast.Hepatocellular carcinoma(HCC)is characterized by arterial-phase hypervascularity and later washout(negative enhancement).Benign nodules such as regenerative nodules or dysplastic nodules are usually isoechoic or slightly hypoechoic in the arterial phase and isoechoic in the late phase.However,there are occasional HCC lesions with atypical enhancement including hypovascular HCC and hypervascular HCC without washout.Cholangiocarcinomas are infrequently detected during HCC surveillance and mostly show rimlike or diffuse hypervascularity followed by rapid washout.Hemangiomas are often found at HCC surveillance and are easily diagnosed by CEUS.CEUS can be effectively used in the diagnostic work-up of small nodules detected at HCC surveillance.CEUS is also useful to differentiate malignant and benign venous thrombosis and to guide and monitor the local ablation therapy for HCC.
