An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement.However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy...An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement.However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy of noninvasive blood pressure measurement, remains rarely addressed. In the present study, finite element（FE） models were constructed to quantify intra-arm stresses generated by cuff compression, aiming to provide some theoretical evidence for identifying factors of importance for blood pressure measurement or explaining clinical observations. Obtained results showed that the simulated tissue stresses were highly sensitive to the distribution of cuff pressure on the arm surface and the contact condition between muscle and bone. In contrast, the magnitude of cuff pressure and small variations in elastic properties of arm soft tissues had little influence on the efficiency of pressure transmission in arm tissues. In particular, it was found that a thickened subcutaneous fat layer in obese subjects significantly reduced the effective pressure transmitted to the brachial artery, which may explain why blood pressure overestimation occurs more frequently in obese subjects in noninvasive blood pressure measurement.展开更多
A method for noninvasive determination of fat and water content in the human body is examined. A spatially resolved spectroscopy method is used which can record low intensity near infrared spectra. This novel approach...A method for noninvasive determination of fat and water content in the human body is examined. A spatially resolved spectroscopy method is used which can record low intensity near infrared spectra. This novel approach is compared to other methods for the determination of fat and water content. Monte Carlo simulations of light propagation in tissue are shown and the production and characterization of optical phantoms of adipose tissue are investigated.展开更多
Background and Aims:Nonalcoholic fatty liver disease(NAFLD)is associated with metabolic disorders.This study aimed to explore the role of metabolic disorders in screening advanced fibrosis in NAFLD patients.Methods:A ...Background and Aims:Nonalcoholic fatty liver disease(NAFLD)is associated with metabolic disorders.This study aimed to explore the role of metabolic disorders in screening advanced fibrosis in NAFLD patients.Methods:A total of 246 histologically-proven NAFLD patients were enrolled across 14 centers.We compared the severity of fibrosis in patients with different components of metabolic disorders.Based on standard noninvasive tests and metabolic disorders,we developed new algorithms to identify advanced fibrosis.Results:Metabolic syndrome(MetS)was frequent in NAFLD patients(133/246,54%).Patients with MetS had a higher proportion of significant fibrosis(p=0.014)and higher LSM values(9.2 kPa,vs.7.4 kPa,p=0.002)than those without MetS.Patients with more metabolic disorders had higher fibrosis stages(p=0.017).Reduced highdensity lipoprotein cholesterol(odds ratio[OR]:2.241,95%confidence interval[CI]:1.004–5.002,p=0.049)and raised fasting glucose(OR:4.500,95%CI:2.083–9.725,p<0.001)were significantly associated with advanced fibrosis.Using these two metabolic disorders as a screening tool,a sensitivity,specificity and accuracy of 92%,81%and 83%was achieved,respectively.With the new algorithms combining metabolic disorders with noninvasive measurements,the number of patients requiring liver biopsy was reduced,especially in combination with the Fibrosis-4 score and metabolic disorders(36%to 17%,p<0.001).In addition,this stepwise algorithm could achieve a high accuracy(85%)and high negative predictive value(93%).Conclusions:Metabolic disorders should be taken into consideration in the diagnosis of advanced fibrosis.With further validation and investigation,new algorithms could be recommended in primary care units to spare patients from unnecessary referral and liver biopsies.展开更多
Nonalcoholic fatty liver disease(NAFLD)has become the most common chronic liver disease worldwide.NAFLD‐related cirrhosis is often complicated by portal hypertension(PHT).Recent evidence showed that portal venous pr...Nonalcoholic fatty liver disease(NAFLD)has become the most common chronic liver disease worldwide.NAFLD‐related cirrhosis is often complicated by portal hypertension(PHT).Recent evidence showed that portal venous pressure(PVP)starts to rise in the early stages of NAFLD,even in absence of advanced fibrosis or cirrhosis.However,the precise pathological mechanisms of this process are still poorly understood.Lipid accumulation,hepatocellular ballooning,sinusoidal endothelial cell dysfunction,capillarization,microthrombosis,increased angiogenesis,and pericellular fibrosis may all be involved in the early development of increased PVP in NAFLD.Direct measurement of PHT is invasive and impractical in noncirrhotic NAFLD individuals and may also underestimate its severity.Thus,the development and validation of noninvasive and more accurate measurements,including new serum biomarkers,scoring models,and imaging techniques(such as ultrasonography,elastography,and magnetic resonance imaging),are urgently needed.Owing to the increasing morbidity,challenges in the prevention and management of PHT in NAFLD are unprecedented.This review article aims to briefly discuss these challenges and summarizes the mechanisms,diagnosis,and emerging therapies for PHT in people with NAFLD.展开更多
基金supported in part by the National Natural Science Foundation of China (Grant 81370438)the SJTU Medical-Engineering Cross-cutting Research Project (Grant YG2015MS53)supported by the Hui-Chun Chin and Tsung-Dao Lee Chinese Undergraduate Research Program Endowment
文摘An inflatable cuff wrapped around the upper arm is widely used in noninvasive blood pressure measurement.However, the mechanical interaction between cuff and arm tissues, a factor that potentially affects the accuracy of noninvasive blood pressure measurement, remains rarely addressed. In the present study, finite element（FE） models were constructed to quantify intra-arm stresses generated by cuff compression, aiming to provide some theoretical evidence for identifying factors of importance for blood pressure measurement or explaining clinical observations. Obtained results showed that the simulated tissue stresses were highly sensitive to the distribution of cuff pressure on the arm surface and the contact condition between muscle and bone. In contrast, the magnitude of cuff pressure and small variations in elastic properties of arm soft tissues had little influence on the efficiency of pressure transmission in arm tissues. In particular, it was found that a thickened subcutaneous fat layer in obese subjects significantly reduced the effective pressure transmitted to the brachial artery, which may explain why blood pressure overestimation occurs more frequently in obese subjects in noninvasive blood pressure measurement.
文摘A method for noninvasive determination of fat and water content in the human body is examined. A spatially resolved spectroscopy method is used which can record low intensity near infrared spectra. This novel approach is compared to other methods for the determination of fat and water content. Monte Carlo simulations of light propagation in tissue are shown and the production and characterization of optical phantoms of adipose tissue are investigated.
基金This study was funded by Sanofi(China)Investment Co.,Ltdthe National Key R&D Program of China(No.2017YFC090890).
文摘Background and Aims:Nonalcoholic fatty liver disease(NAFLD)is associated with metabolic disorders.This study aimed to explore the role of metabolic disorders in screening advanced fibrosis in NAFLD patients.Methods:A total of 246 histologically-proven NAFLD patients were enrolled across 14 centers.We compared the severity of fibrosis in patients with different components of metabolic disorders.Based on standard noninvasive tests and metabolic disorders,we developed new algorithms to identify advanced fibrosis.Results:Metabolic syndrome(MetS)was frequent in NAFLD patients(133/246,54%).Patients with MetS had a higher proportion of significant fibrosis(p=0.014)and higher LSM values(9.2 kPa,vs.7.4 kPa,p=0.002)than those without MetS.Patients with more metabolic disorders had higher fibrosis stages(p=0.017).Reduced highdensity lipoprotein cholesterol(odds ratio[OR]:2.241,95%confidence interval[CI]:1.004–5.002,p=0.049)and raised fasting glucose(OR:4.500,95%CI:2.083–9.725,p<0.001)were significantly associated with advanced fibrosis.Using these two metabolic disorders as a screening tool,a sensitivity,specificity and accuracy of 92%,81%and 83%was achieved,respectively.With the new algorithms combining metabolic disorders with noninvasive measurements,the number of patients requiring liver biopsy was reduced,especially in combination with the Fibrosis-4 score and metabolic disorders(36%to 17%,p<0.001).In addition,this stepwise algorithm could achieve a high accuracy(85%)and high negative predictive value(93%).Conclusions:Metabolic disorders should be taken into consideration in the diagnosis of advanced fibrosis.With further validation and investigation,new algorithms could be recommended in primary care units to spare patients from unnecessary referral and liver biopsies.
基金National Natural Science Foundation of China,Grant/Award Number:82070588Agenzia Italiana del Farmaco,Ministero della Salute,Grant/Award Number:RF‐2016‐02364358。
文摘Nonalcoholic fatty liver disease(NAFLD)has become the most common chronic liver disease worldwide.NAFLD‐related cirrhosis is often complicated by portal hypertension(PHT).Recent evidence showed that portal venous pressure(PVP)starts to rise in the early stages of NAFLD,even in absence of advanced fibrosis or cirrhosis.However,the precise pathological mechanisms of this process are still poorly understood.Lipid accumulation,hepatocellular ballooning,sinusoidal endothelial cell dysfunction,capillarization,microthrombosis,increased angiogenesis,and pericellular fibrosis may all be involved in the early development of increased PVP in NAFLD.Direct measurement of PHT is invasive and impractical in noncirrhotic NAFLD individuals and may also underestimate its severity.Thus,the development and validation of noninvasive and more accurate measurements,including new serum biomarkers,scoring models,and imaging techniques(such as ultrasonography,elastography,and magnetic resonance imaging),are urgently needed.Owing to the increasing morbidity,challenges in the prevention and management of PHT in NAFLD are unprecedented.This review article aims to briefly discuss these challenges and summarizes the mechanisms,diagnosis,and emerging therapies for PHT in people with NAFLD.
