BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disea-se.The accuracy of noninvasive biomarkers for detecting hepatic steatosis is still limited.AIM To assess the diagnostic performa...BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disea-se.The accuracy of noninvasive biomarkers for detecting hepatic steatosis is still limited.AIM To assess the diagnostic performance of noninvasive steatosis biomarkers in diag-nosing NAFLD using magnetic resonance imaging proton density fat fraction(MRI-PDFF)as the gold standard.METHODS A total of 131 suspected NAFLD patients(60%male,median age 36 years)under-going MRI-PDFF were consecutively recruited from a tertiary hospital.Steatosis grades determined by MRI-PDFF were classified as none(<5%),mild(5%-11%),moderate(11%-17%),and severe(≥17%).Six steatosis biomarkers were calculated according to clinical parameters and laboratory tests,including fatty liver index,hepatic steatosis index,ZJU index,Framingham steatosis index,triglycerides and glucose index,and visceral adiposity index.The accuracy of these biomarkers in detecting hepatic steatosis was evaluated using the area under the receiver operating characteristic curves(AUCs).The Youden index was used to determine the optimal cut-off for each biomarker.The linear trend analysis of each biomarker across the steatosis grades was conducted by Mantel-Haenszelχ2 test.Spearman's rank correlation assessed the relationship between steatosis biomarkers and MRI-PDFF.RESULTS Steatosis grades based on MRI-PDFF prevalence were:None 27%,mild 40%,moderate 15%and severe 18%.Six steatosis biomarkers showed a linear trend across the steatosis grades and a significant positive correlation with MRI-PDFF.The six steatosis biomarkers demonstrated AUCs near 0.90(range:0.857-0.912,all P<0.001)for diagnosing NAFLD by MRI-PDFF≥5%.The optimal cut-offs showed sensitivity between 84.4%-91.7%and specificity between 71.4%-85.7%.The diagnostic performance of these biomarkers in detecting moderate-to-severe and severe steatosis was relatively weaker.CONCLUSION These noninvasive steatosis biomarkers accurately diagnosed NAFLD and correlated well with MRI-PDFF for detecting NAFLD,but they did not effectively detect moderate or severe steatosis.展开更多
We perform a statistical analysis of data from the Mars Atmosphere and Volatile Evolution (MAVEN) project on the global distribution of protons in the Martian magnetosheath. Our results show that the proton number den...We perform a statistical analysis of data from the Mars Atmosphere and Volatile Evolution (MAVEN) project on the global distribution of protons in the Martian magnetosheath. Our results show that the proton number density distribution has a south-north asymmetry. This south-north asymmetry is most likely caused by the south-north asymmetric distributions of the crustal magnetic fields at Mars. The strong crustal magnetic fields push the inner boundary of magnetosheath to a higher altitude in the southern hemisphere. Due to the outward movement of the inner boundary of the magnetosheath, a compressed magnetosheath forms, causing subsequent increases in proton number density, thermal pressure, and total pressure. Eventually, a balance is reached between the increased total pressure inside the magnetosheath and the increased magnetic pressure inside the induced magnetosphere. Our statistical study suggests that the Martian crustal magnetic fields can strongly affect the proton number density distribution in the Martian magnetosheath.展开更多
Purpose: Bone marrow and muscle adiposity have been considered to correlate with osteoporosis and Sarcopenia. Proton Density Fat Fraction (PDFF) can be measured by Magnetic Resonance Imaging (MRI). The purpose of the ...Purpose: Bone marrow and muscle adiposity have been considered to correlate with osteoporosis and Sarcopenia. Proton Density Fat Fraction (PDFF) can be measured by Magnetic Resonance Imaging (MRI). The purpose of the present study was to measure PDFF in the lumbar spine, paraspinal muscle and subcutaneous fat tissue. Methods: Participants were comprised of 30 patients (18 males, 12 females;age range, 14 - 87 years) who underwent MRI due to low back symptoms. PDFFs for the body of the fourth lumbar vertebra (L4), paraspinal muscle, and subcutaneous fat were measured. Results: PDFFs of the vertebral body and subcutaneous fat were significantly higher than that of paraspinal muscle (p < 0.001). PDFF was significantly higher for subcutaneous fat than for the vertebral body (p < 0.001). Although no significant differences in PDFF of the vertebral body, paraspinal muscle, and subcutaneous fat between females and males, PDFFs of the vertebral body and paraspinal muscle were significantly higher in older subjects (>63 years) than in younger subjects (Conclusions: PDFF of the vertebral body was significantly higher than that of paraspinal muscle. PDFFs of the vertebral body and paraspinal muscle were significantly lower in younger subjects than in older subjects.展开更多
BACKGROUND Hepatic steatosis is a very common problem worldwide.AIM To assess the performance of two-and six-point Dixon magnetic resonance(MR)techniques in the detection,quantification and grading of hepatic steatosi...BACKGROUND Hepatic steatosis is a very common problem worldwide.AIM To assess the performance of two-and six-point Dixon magnetic resonance(MR)techniques in the detection,quantification and grading of hepatic steatosis.METHODS A single-center retrospective study was performed in 62 patients with suspected parenchymal liver disease.MR sequences included two-point Dixon,six-point Dixon,MR spectroscopy(MRS)and MR elastography.Fat fraction(FF)estimates on the Dixon techniques were compared to the MRS-proton density FF(PDFF).Statistical tests used included Pearson’s correlation and receiver operating characteristic.RESULTS FF estimates on the Dixon techniques showed excellent correlation(≥0.95)with MRS-PDFF,and excellent accuracy[area under the receiver operating characteristic(AUROC)≥0.95]in:(1)Detecting steatosis;and(2)Grading severe steatosis,(P<0.001).In iron overload,two-point Dixon was not evaluable due to confounding T2*effects.FF estimates on six-point Dixon vs MRS-PDFF showed a moderate correlation(0.82)in iron overload vs an excellent correlation(0.97)without iron overload,(P<0.03).The accuracy of six-point Dixon in grading mild steatosis improved(AUROC:0.59 to 0.99)when iron overload cases were excluded.The excellent correlation(>0.9)between the Dixon techniques vs MRSPDFF did not change in the presence of liver fibrosis(P<0.01).CONCLUSION Dixon techniques performed satisfactorily for the evaluation of hepatic steatosis but with exceptions.展开更多
Background Type II diabetes mellitus usually related to visceral and other organ （ectopic） fat. The purpose of this study was to detect hepatic and pancreatic fat infiltration in type II diabetes meUitus patients us...Background Type II diabetes mellitus usually related to visceral and other organ （ectopic） fat. The purpose of this study was to detect hepatic and pancreatic fat infiltration in type II diabetes meUitus patients using 3.0T magnetic resonance （MR） and to compare the performance of iterative decomposition of water and fat with echo asymmetry and least-squares estimation （IDEAL-Quant） with single-voxel proton spectroscopy （HI-MRS）. Methods The study protocol was approved by our Institutional Review Board. Written informed consent was obtained from each subject in this study. We prospectively performed IDEAL-Quant and single-voxel proton spectroscopy with an echo time of 35 ms on 24 type II diabetes patients and 10 healthy volunteers. The hepatic proton density fat fraction （HPDFF） and pancreatic proton density fat fraction （PPDFF） were calculated, compared, and analyzed by t-tests and Spearman＇s correlation. Results The HPDFF and PPDFF measured with IDEAL-Quant were significantly different between the healthy volunteers and type II diabetes patients （th=9.377, P=0.000; tp=2.813, P=0.008）. The HPDFF and PPDFF measured with MRS were also significantly different between the healthy volunteers and type II diabetes patients （th=5.342, P=0.000; tp=2.63, P=0.013）. The HPDFF and PPDFF measured by the two methods were in good agreement （rh=0.854, P=-0.000; rp=0.774, P=0.000）. The HPDFF and PPDFF were not significantly correlated with each other （rMRs=0.203, p=0.248; rpDEAL_Quant=0.301, P=0.084）. The PPDFF measured with IDEAL-Quant was associated with body mass index （t=0.377, P=0.028）. Conclusion IDEAL-Quant is a nice method for hepatic and pancreatic fat detection, and it can be applied in clinical practice.展开更多
Quantification of hepatic fat and iron content is important for early detection and monitoring of nonalcoholic fatty liver disease(NAFLD) patients. This study evaluated quantification efficiency of hepatic proton dens...Quantification of hepatic fat and iron content is important for early detection and monitoring of nonalcoholic fatty liver disease(NAFLD) patients. This study evaluated quantification efficiency of hepatic proton density fat fraction(PDFF) by MRI using NAFLD rabbits. R2* was also measured to investigate whether it correlates with fat levels in NAFLD. NAFLD rabbit model was successfully established by high fat and cholesterol diet. Rabbits underwent MRI examination for fat and iron analyses,compared with liver histological findings. MR examinations were performed on a 3.0 T MR system using multi-echo 3 D gradient recalled echo(GRE) sequence. MRI-PDFF showed significant differences between different steatosis grades with medians of3.72%(normal), 5.43%(mild), 9.11%(moderate) and 11.17%(severe), whereas this was not observed in R2*. Close correlation between MRI-PDFF and histological steatosis was observed(r=0.78, P=0.000). Hepatic iron deposit was not found in any rabbits. There was no correlation between R2* and either liver MRI-PDFF or histological steatosis. MR measuring MRI-PDFF and R2* simultaneously provides promising quantification of steatosis and iron. Rabbit NAFLD model confirmed accuracy of MRI-PDFF for liver fat quantification. R2* measurement and relationship between fat and iron of NAFLD liver need further experimental investigation.展开更多
Background Detection rate of retropharyngeal lymph node metastasis in patients with nasopharyngeal carcinoma （NPC） needs to be improved. The purpose of this study was to compare three magnetic resonance （MR） seque...Background Detection rate of retropharyngeal lymph node metastasis in patients with nasopharyngeal carcinoma （NPC） needs to be improved. The purpose of this study was to compare three magnetic resonance （MR） sequences for detecting lymph nodes in patients with NPC. Methods Between July 2007 and March 2008, MR staging of pre-treated tumor was conducted on 120 patients with pathologically confirmed NPC. The outcome of three different sequences for MR NPC staging were compared： coronal short T1 inversion recovery （STIR）, axial proton density fat-suppressed （PDWI fs）, and coronal contrast enhanced fast spin echo T1 weighted fat-suppressed （CE FSE TlWl fs）. Nodal classification method （1999） was applied to count the number of retropharyngeal and cervical lymph nodes discovered by each MR sequence. Paired t tests were used for statistical analysis. Results A total of 2575 lymph nodes were found using coronal STIR sequence; 1816 lymph nodes for coronal CE FSE TIWI fs sequence and 2638 lymph nodes for axial PDWl fs sequence. Significant differences existed in the number of lymph nodes detected by axial PDWI fs and coronal CE FSE T1WI fs sequence （paired t test, P 〈0.05）, with the former sequence getting higher numbers. Statistical differences also existed between coronal STIR and coronal CE FSE TlWl fs sequence （paired ttest, P 〈0.05）, with the former sequence getting higher numbers. No significant difference was found between coronal STIR sequence and axial PDWI fs sequence （paired ttest, P 〉0.05）. Conclusions For the detection of retropharyngeal and cervical lymph nodes, coronal STIR sequence and axial PDWI fs sequence have similar performance and both sequences showed better detection than CE FSE TIWI fs sequence. Furthermore, by combining coronal STIR sequence and axial PDWI fs sequence, we can improve the detection of lymph nodes in NPC N-staging before treatment, especially for lymph nodes located in the thoracic entrance.展开更多
Background and Aims:The redefinition of metabolic-as-sociated fatty liver disease(MAFLD)from nonalcoholic fat-ty liver disease(NAFLD)has caused a revolution in clinical practice,and the characteristics of patients wit...Background and Aims:The redefinition of metabolic-as-sociated fatty liver disease(MAFLD)from nonalcoholic fat-ty liver disease(NAFLD)has caused a revolution in clinical practice,and the characteristics of patients with steatosis but not MAFLD remain unclear.The aims were to compare the diagnosis rate of MAFLD in NAFLD using different steato-sis methods and explore the features of non-MAFLD-NAFLD and MAFLD-non-NAFLD.Methods:A cross-sectional study enrolling consecutive individuals was conducted at three medical centers in southern China from January 2015 to September 2020.Steatosis was evaluated by liver biopsy or magnetic resonance imaging-based proton density fat frac-tion(MRI-PDFF),ultrasound,controlled attenuation param-eter(CAP),and fatty liver index(FLI).Fibrosis was assessed by the NAFLD fibrosis score,transient elastography,or shear wave elastography.Results:The study enrolled 14,985 Chi-nese adults.The agreement of MAFLD and NAFLD diagnoses were 83%for FLI,95%for ultrasound,94%for both CAP and MRI-PDFF,and 95%for liver biopsy.The body mass index,blood pressure and lipid levels among non-MAFLD-NAFLD pa-tients were similar metabolic parameters(p>0.05 for all),but not the alanine aminotransferase and the proportion of pa-tients with insulin resistance,which were significantly higher in non-MAFLD-NAFLD with significant fibrosis.Conclusions:The new MAFLD definition ruled out 5-17%of NAFLD cases.NAFLD and MAFLD-NAFLD involved more severe metabolic abnormalities than MAFLD and MAFLD-non-NAFLD.Non-MAFLD-NAFLD patients with significant fibrosis had more se-vere liver injury and increased glycemic dysregulation within the normal range.Attention should be paid to its progression.展开更多
The extoic structure of 29P was investigated by measuring its magnetic moment in the ground state with β-NMR method. We got the experimental value of 1.2346 μN after diamagnetism correction. It is very close to the ...The extoic structure of 29P was investigated by measuring its magnetic moment in the ground state with β-NMR method. We got the experimental value of 1.2346 μN after diamagnetism correction. It is very close to the calculated value of 1.1009 μN computed with shell model. The shell model calculation also gave a proton density distribution of 29P with a long tail. The present results show that 2s1/2 proton in the 29P may lead to the proton-skin structure.展开更多
Genetic susceptibility to metabolic associated fatty liver disease(MAFLD)is complex and poorly characterized.Accurate characterization of the genetic background of hepatic fat content would provide insights into disea...Genetic susceptibility to metabolic associated fatty liver disease(MAFLD)is complex and poorly characterized.Accurate characterization of the genetic background of hepatic fat content would provide insights into disease etiology and causality of risk factors.We performed genome-wide association study(GWAS)on two noninvasive definitions of hepatic fat content:magnetic resonance imaging proton density fat fraction(MRI-PDFF)in 16,050 participants and fatty liver index(FLI)in 388,701 participants from the United Kingdom(UK)Biobank(UKBB).Heritability,genetic overlap,and similarity between hepatic fat content phenotypes were analyzed,and replicated in 10,398 participants from the University Medical Center Groningen(UMCG)Genetics Lifelines Initiative(UGLI).Meta-analysis of GWASs of MRI-PDFF in UKBB revealed five statistically significant loci,including two novel genomic loci harboring CREB3L1(rs72910057-T,P=5.40E−09)and GCM1(rs1491489378-T,P=3.16E−09),respectively,as well as three previously reported loci:PNPLA3,TM6SF2,and APOE.GWAS of FLI in UKBB identified 196 genome-wide significant loci,of which 49 were replicated in UGLI,with top signals in ZPR1(P=3.35E−13)and FTO(P=2.11E−09).Statistically significant genetic correlation(rg)between MRI-PDFF(UKBB)and FLI(UGLI)GWAS results was found(rg=0.5276,P=1.45E−03).Novel MRI-PDFF genetic signals(CREB3L1 and GCM1)were replicated in the FLI GWAS.We identified two novel genes for MRI-PDFF and 49 replicable loci for FLI.Despite a difference in hepatic fat content assessment between MRI-PDFF and FLI,a substantial similar genetic architecture was found.FLI is identified as an easy and reliable approach to study hepatic fat content at the population level.展开更多
Metabolic dysfunction associated steatohepatitis(MASH)is a silent epidemic,hiding in the shadows of obesity,and often silently advancing towards the grave complication of cirrhosis.The distinction between MASH and sim...Metabolic dysfunction associated steatohepatitis(MASH)is a silent epidemic,hiding in the shadows of obesity,and often silently advancing towards the grave complication of cirrhosis.The distinction between MASH and simple hepatic steatosis,which is under the spectrum of metabolic dysfunction-associated steatotic liver disease(MASLD),is highly desired as it provides critical information about the prognosis of the patient.Noninvasive indicators,such as fibrosis-4(FIB-4)index and nonalcoholic fatty liver disease(NAFLD)fibrosis score that includes conventional laboratory data and clinical parameters.展开更多
Background:High liver fat content(LFC)induces increased risks of both hepatic and extrahepatic progression in metabolic dysfunction-associated steatotic liver disease(MASLD),while maintaining a significant decline in ...Background:High liver fat content(LFC)induces increased risks of both hepatic and extrahepatic progression in metabolic dysfunction-associated steatotic liver disease(MASLD),while maintaining a significant decline in magnetic resonance imaging-based proton density fat fraction(MRI-PDFF)(≥30%decline relative to baseline)without worsening fibrosis results in improved histological severity and prognosis.However,the factors associated with the loss of sustained responses to treatment remain unclear,and we aim to identify them.Methods:Consecutive treatment-naïve MASLD patients between January 2015 and February 2022,with follow-up until April 2023,were included in this prospective cohort study.LFC quantified by MRI-PDFF and liver stiffness measurements(LSM)determined by two-dimensional shear wave elastography(2D-SWE)were evaluated at weeks 0,24 and 48.MRI-PDFF response was defined as a≥30%relative decline in PDFF values,and LSM response was defined as a≥1 stage decline from baseline.Results:A total of 602 MASLD patients were enrolled.Of the 303 patients with a 24-week MRI-PDFF response and complete follow-up of 48 weeks,the rate of loss of MRI-PDFF response was 29.4%,and multivariable logistic regression analyses showed that 24-week insulin resistance(IR),still regular exercise and caloric restriction after 24 weeks,and the relative decline in LFC were risk factors for loss of MRI-PDFF response.Loss of LSM response at 48 weeks occurred in 15.9%of patients,and multivariable analysis confirmed 24-week serum total bile acid(TBA)levels and the relative decline in TBA from baseline as independent predictors.No significant association was found at 48 weeks between loss of MRI-PDFF response and loss of LSM response.Conclusions:MASLD patients with IR and high TBA levels are at higher risks of subsequent diminished sustained improvements of steatosis and fibrosis,respectively.展开更多
The application of laser pulses with psec or shorter duration enables nonthermal efficient ultrahigh acceleration of plasma blocks with homogeneous high ion energies exceeding ion current densities of 10^(12) A cm^(-2...The application of laser pulses with psec or shorter duration enables nonthermal efficient ultrahigh acceleration of plasma blocks with homogeneous high ion energies exceeding ion current densities of 10^(12) A cm^(-2). The effects of ultrahigh acceleration of plasma blocks with high energy proton beams are proposed for muon production in a compact magnetic fusion device. The proposed new scheme consists of an ignition fusion spark by muon catalyzed fusion(μCF) in a small mirror-like configuration where low temperature D–T plasma is trapped for a duration of 1 μs. This initial fusion spark produces sufficient alpha heating in order to initiate the fusion process in the main device. The use of a multi-fluid global particle and energy balance code allows us to follow the temporal evolution of the reaction rate of the fusion process in the device. Recent progress on the ICAN and IZEST projects for high efficient high power and high repetition rate laser systems allows development of the proposed device for clean energy production. With the proposed approaches,experiments on fusion nuclear reactions and μCF process can be performed in magnetized plasmas in existing kJ/PW laser facilities as the GEKKO-LFEX, the PETAL and the ORION or in the near future laser facilities as the ELI-NP Romanian pillar.展开更多
A model for the nuclear medium modification of parton densities is presented.The approach is based on a global analysis of available deep inelastic scattering data for different nuclear targets within the rescaling mo...A model for the nuclear medium modification of parton densities is presented.The approach is based on a global analysis of available deep inelastic scattering data for different nuclear targets within the rescaling model,combined with the effects of Fermi motion.The scale dependence is implemented through the DGLAP-evolved quark and gluon densities in a proton derived analytically at the leading order of QCD coupling.By fitting the rescaling parameters to experimental data on the ratio F^(2)^(A)(x,Q^(2))/F_(2)^(A′)(x,Q^(2))for several nuclear targets A and A',we obtain predictions for nuclear parton distributions,even for unmeasured nuclei.The effects of nuclear modifications are investigated with respect to the mass number A.We highlight distinct shadowing and antishadowing behaviors for gluons and quarks.展开更多
基金Supported by the Leap-forward Development Program for Beijing Biopharmaceutical Industry(G20),No.Z171100001717008the Fundamental Research Funds for the Central Universities and Research projects on biomedical transformation of China-Japan Friendship Hospital,No.PYBZ1815.
文摘BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disea-se.The accuracy of noninvasive biomarkers for detecting hepatic steatosis is still limited.AIM To assess the diagnostic performance of noninvasive steatosis biomarkers in diag-nosing NAFLD using magnetic resonance imaging proton density fat fraction(MRI-PDFF)as the gold standard.METHODS A total of 131 suspected NAFLD patients(60%male,median age 36 years)under-going MRI-PDFF were consecutively recruited from a tertiary hospital.Steatosis grades determined by MRI-PDFF were classified as none(<5%),mild(5%-11%),moderate(11%-17%),and severe(≥17%).Six steatosis biomarkers were calculated according to clinical parameters and laboratory tests,including fatty liver index,hepatic steatosis index,ZJU index,Framingham steatosis index,triglycerides and glucose index,and visceral adiposity index.The accuracy of these biomarkers in detecting hepatic steatosis was evaluated using the area under the receiver operating characteristic curves(AUCs).The Youden index was used to determine the optimal cut-off for each biomarker.The linear trend analysis of each biomarker across the steatosis grades was conducted by Mantel-Haenszelχ2 test.Spearman's rank correlation assessed the relationship between steatosis biomarkers and MRI-PDFF.RESULTS Steatosis grades based on MRI-PDFF prevalence were:None 27%,mild 40%,moderate 15%and severe 18%.Six steatosis biomarkers showed a linear trend across the steatosis grades and a significant positive correlation with MRI-PDFF.The six steatosis biomarkers demonstrated AUCs near 0.90(range:0.857-0.912,all P<0.001)for diagnosing NAFLD by MRI-PDFF≥5%.The optimal cut-offs showed sensitivity between 84.4%-91.7%and specificity between 71.4%-85.7%.The diagnostic performance of these biomarkers in detecting moderate-to-severe and severe steatosis was relatively weaker.CONCLUSION These noninvasive steatosis biomarkers accurately diagnosed NAFLD and correlated well with MRI-PDFF for detecting NAFLD,but they did not effectively detect moderate or severe steatosis.
基金funded by the Science and Technology Development Fund, Macao SAR (File no.0035/2018/AFJ)the National Natural Science Foundation of China (NSFC) under grants 41564007 and 41731067
文摘We perform a statistical analysis of data from the Mars Atmosphere and Volatile Evolution (MAVEN) project on the global distribution of protons in the Martian magnetosheath. Our results show that the proton number density distribution has a south-north asymmetry. This south-north asymmetry is most likely caused by the south-north asymmetric distributions of the crustal magnetic fields at Mars. The strong crustal magnetic fields push the inner boundary of magnetosheath to a higher altitude in the southern hemisphere. Due to the outward movement of the inner boundary of the magnetosheath, a compressed magnetosheath forms, causing subsequent increases in proton number density, thermal pressure, and total pressure. Eventually, a balance is reached between the increased total pressure inside the magnetosheath and the increased magnetic pressure inside the induced magnetosphere. Our statistical study suggests that the Martian crustal magnetic fields can strongly affect the proton number density distribution in the Martian magnetosheath.
文摘Purpose: Bone marrow and muscle adiposity have been considered to correlate with osteoporosis and Sarcopenia. Proton Density Fat Fraction (PDFF) can be measured by Magnetic Resonance Imaging (MRI). The purpose of the present study was to measure PDFF in the lumbar spine, paraspinal muscle and subcutaneous fat tissue. Methods: Participants were comprised of 30 patients (18 males, 12 females;age range, 14 - 87 years) who underwent MRI due to low back symptoms. PDFFs for the body of the fourth lumbar vertebra (L4), paraspinal muscle, and subcutaneous fat were measured. Results: PDFFs of the vertebral body and subcutaneous fat were significantly higher than that of paraspinal muscle (p < 0.001). PDFF was significantly higher for subcutaneous fat than for the vertebral body (p < 0.001). Although no significant differences in PDFF of the vertebral body, paraspinal muscle, and subcutaneous fat between females and males, PDFFs of the vertebral body and paraspinal muscle were significantly higher in older subjects (>63 years) than in younger subjects (Conclusions: PDFF of the vertebral body was significantly higher than that of paraspinal muscle. PDFFs of the vertebral body and paraspinal muscle were significantly lower in younger subjects than in older subjects.
文摘BACKGROUND Hepatic steatosis is a very common problem worldwide.AIM To assess the performance of two-and six-point Dixon magnetic resonance(MR)techniques in the detection,quantification and grading of hepatic steatosis.METHODS A single-center retrospective study was performed in 62 patients with suspected parenchymal liver disease.MR sequences included two-point Dixon,six-point Dixon,MR spectroscopy(MRS)and MR elastography.Fat fraction(FF)estimates on the Dixon techniques were compared to the MRS-proton density FF(PDFF).Statistical tests used included Pearson’s correlation and receiver operating characteristic.RESULTS FF estimates on the Dixon techniques showed excellent correlation(≥0.95)with MRS-PDFF,and excellent accuracy[area under the receiver operating characteristic(AUROC)≥0.95]in:(1)Detecting steatosis;and(2)Grading severe steatosis,(P<0.001).In iron overload,two-point Dixon was not evaluable due to confounding T2*effects.FF estimates on six-point Dixon vs MRS-PDFF showed a moderate correlation(0.82)in iron overload vs an excellent correlation(0.97)without iron overload,(P<0.03).The accuracy of six-point Dixon in grading mild steatosis improved(AUROC:0.59 to 0.99)when iron overload cases were excluded.The excellent correlation(>0.9)between the Dixon techniques vs MRSPDFF did not change in the presence of liver fibrosis(P<0.01).CONCLUSION Dixon techniques performed satisfactorily for the evaluation of hepatic steatosis but with exceptions.
文摘Background Type II diabetes mellitus usually related to visceral and other organ （ectopic） fat. The purpose of this study was to detect hepatic and pancreatic fat infiltration in type II diabetes meUitus patients using 3.0T magnetic resonance （MR） and to compare the performance of iterative decomposition of water and fat with echo asymmetry and least-squares estimation （IDEAL-Quant） with single-voxel proton spectroscopy （HI-MRS）. Methods The study protocol was approved by our Institutional Review Board. Written informed consent was obtained from each subject in this study. We prospectively performed IDEAL-Quant and single-voxel proton spectroscopy with an echo time of 35 ms on 24 type II diabetes patients and 10 healthy volunteers. The hepatic proton density fat fraction （HPDFF） and pancreatic proton density fat fraction （PPDFF） were calculated, compared, and analyzed by t-tests and Spearman＇s correlation. Results The HPDFF and PPDFF measured with IDEAL-Quant were significantly different between the healthy volunteers and type II diabetes patients （th=9.377, P=0.000; tp=2.813, P=0.008）. The HPDFF and PPDFF measured with MRS were also significantly different between the healthy volunteers and type II diabetes patients （th=5.342, P=0.000; tp=2.63, P=0.013）. The HPDFF and PPDFF measured by the two methods were in good agreement （rh=0.854, P=-0.000; rp=0.774, P=0.000）. The HPDFF and PPDFF were not significantly correlated with each other （rMRs=0.203, p=0.248; rpDEAL_Quant=0.301, P=0.084）. The PPDFF measured with IDEAL-Quant was associated with body mass index （t=0.377, P=0.028）. Conclusion IDEAL-Quant is a nice method for hepatic and pancreatic fat detection, and it can be applied in clinical practice.
文摘Quantification of hepatic fat and iron content is important for early detection and monitoring of nonalcoholic fatty liver disease(NAFLD) patients. This study evaluated quantification efficiency of hepatic proton density fat fraction(PDFF) by MRI using NAFLD rabbits. R2* was also measured to investigate whether it correlates with fat levels in NAFLD. NAFLD rabbit model was successfully established by high fat and cholesterol diet. Rabbits underwent MRI examination for fat and iron analyses,compared with liver histological findings. MR examinations were performed on a 3.0 T MR system using multi-echo 3 D gradient recalled echo(GRE) sequence. MRI-PDFF showed significant differences between different steatosis grades with medians of3.72%(normal), 5.43%(mild), 9.11%(moderate) and 11.17%(severe), whereas this was not observed in R2*. Close correlation between MRI-PDFF and histological steatosis was observed(r=0.78, P=0.000). Hepatic iron deposit was not found in any rabbits. There was no correlation between R2* and either liver MRI-PDFF or histological steatosis. MR measuring MRI-PDFF and R2* simultaneously provides promising quantification of steatosis and iron. Rabbit NAFLD model confirmed accuracy of MRI-PDFF for liver fat quantification. R2* measurement and relationship between fat and iron of NAFLD liver need further experimental investigation.
基金This study was supported by a grant from the Natural Science Foundation of Fujian Province （No. 2004Y008）.
文摘Background Detection rate of retropharyngeal lymph node metastasis in patients with nasopharyngeal carcinoma （NPC） needs to be improved. The purpose of this study was to compare three magnetic resonance （MR） sequences for detecting lymph nodes in patients with NPC. Methods Between July 2007 and March 2008, MR staging of pre-treated tumor was conducted on 120 patients with pathologically confirmed NPC. The outcome of three different sequences for MR NPC staging were compared： coronal short T1 inversion recovery （STIR）, axial proton density fat-suppressed （PDWI fs）, and coronal contrast enhanced fast spin echo T1 weighted fat-suppressed （CE FSE TlWl fs）. Nodal classification method （1999） was applied to count the number of retropharyngeal and cervical lymph nodes discovered by each MR sequence. Paired t tests were used for statistical analysis. Results A total of 2575 lymph nodes were found using coronal STIR sequence; 1816 lymph nodes for coronal CE FSE TIWI fs sequence and 2638 lymph nodes for axial PDWl fs sequence. Significant differences existed in the number of lymph nodes detected by axial PDWI fs and coronal CE FSE T1WI fs sequence （paired t test, P 〈0.05）, with the former sequence getting higher numbers. Statistical differences also existed between coronal STIR and coronal CE FSE TlWl fs sequence （paired ttest, P 〈0.05）, with the former sequence getting higher numbers. No significant difference was found between coronal STIR sequence and axial PDWI fs sequence （paired ttest, P 〉0.05）. Conclusions For the detection of retropharyngeal and cervical lymph nodes, coronal STIR sequence and axial PDWI fs sequence have similar performance and both sequences showed better detection than CE FSE TIWI fs sequence. Furthermore, by combining coronal STIR sequence and axial PDWI fs sequence, we can improve the detection of lymph nodes in NPC N-staging before treatment, especially for lymph nodes located in the thoracic entrance.
基金National Natural Science Foundation of China(81870404,81670518,81170392)Guangdong Science and Technology Department(2014A020212118)+1 种基金Chinese Foundation for Hepatitis Prevention and Control(TQGB20140083)China postdoctoral science foundation(2020M683128).
文摘Background and Aims:The redefinition of metabolic-as-sociated fatty liver disease(MAFLD)from nonalcoholic fat-ty liver disease(NAFLD)has caused a revolution in clinical practice,and the characteristics of patients with steatosis but not MAFLD remain unclear.The aims were to compare the diagnosis rate of MAFLD in NAFLD using different steato-sis methods and explore the features of non-MAFLD-NAFLD and MAFLD-non-NAFLD.Methods:A cross-sectional study enrolling consecutive individuals was conducted at three medical centers in southern China from January 2015 to September 2020.Steatosis was evaluated by liver biopsy or magnetic resonance imaging-based proton density fat frac-tion(MRI-PDFF),ultrasound,controlled attenuation param-eter(CAP),and fatty liver index(FLI).Fibrosis was assessed by the NAFLD fibrosis score,transient elastography,or shear wave elastography.Results:The study enrolled 14,985 Chi-nese adults.The agreement of MAFLD and NAFLD diagnoses were 83%for FLI,95%for ultrasound,94%for both CAP and MRI-PDFF,and 95%for liver biopsy.The body mass index,blood pressure and lipid levels among non-MAFLD-NAFLD pa-tients were similar metabolic parameters(p>0.05 for all),but not the alanine aminotransferase and the proportion of pa-tients with insulin resistance,which were significantly higher in non-MAFLD-NAFLD with significant fibrosis.Conclusions:The new MAFLD definition ruled out 5-17%of NAFLD cases.NAFLD and MAFLD-NAFLD involved more severe metabolic abnormalities than MAFLD and MAFLD-non-NAFLD.Non-MAFLD-NAFLD patients with significant fibrosis had more se-vere liver injury and increased glycemic dysregulation within the normal range.Attention should be paid to its progression.
基金Supported by National Natural Science Foundation of China (10505032,10435010)
文摘The extoic structure of 29P was investigated by measuring its magnetic moment in the ground state with β-NMR method. We got the experimental value of 1.2346 μN after diamagnetism correction. It is very close to the calculated value of 1.1009 μN computed with shell model. The shell model calculation also gave a proton density distribution of 29P with a long tail. The present results show that 2s1/2 proton in the 29P may lead to the proton-skin structure.
基金supported by the Netherlands Organization for Scientific Research NWO(Grant No.175.010.2007.006)the Economic Structure Enhancing Fund of the Dutch government+20 种基金the Ministry of Economic Affairsthe Ministry of Education,Culture,and Sciencethe Ministry for Health,Welfare,and Sportsthe Northern Netherlands Alliancethe Province of Groningen,University Medical Center Groningenthe University of Groningen,Dutch Kidney Foundation,and Dutch Diabetes Research Foundationsupported by the Dutch Heart Foundation IN-CONTROL(Grant No.CVON2018-27)the ERC Consolidator Grant(Grant No.101001678)the NWO VICI(Grant No.VI.C.202.022)the Netherlands Organ-on-Chip Initiative,an NWO Gravitation project(Grant No.024.003.001)funded by the Ministry of Education,CultureScience of the government of The Netherlandssupported by the Chinese Scholarship Council.Dasha V.Zhernakova was supported by the NWO VENI(Grant No.194.006)supported by the Seerave Foundation.Rinse K.Weersma and Ranko Gacesa were supported by the TIMID project(Grant No.LSHM18057-SGF)financed by the PPP Allowance made available by Top Sector Life Sciences&Health to Samenwerkende Gezondheidsfondsen(SGF)to stimulate public–private partnerships and co-financing by health foundations that are part of the SGFsupported by the NWO VENI(Grant No.09150161810030)the Health∼Holland Public Private Partnership from the Dutch Ministry of Economic Affairs(Grant No.#PPP-2019-024)supported by the UK Medical Research Council and Wellcome Trustthe UK Department of Healththe Scottish and Welsh Governmentsthe North West Development Agencythe British Heart Foundationthe Diabetes UK.
文摘Genetic susceptibility to metabolic associated fatty liver disease(MAFLD)is complex and poorly characterized.Accurate characterization of the genetic background of hepatic fat content would provide insights into disease etiology and causality of risk factors.We performed genome-wide association study(GWAS)on two noninvasive definitions of hepatic fat content:magnetic resonance imaging proton density fat fraction(MRI-PDFF)in 16,050 participants and fatty liver index(FLI)in 388,701 participants from the United Kingdom(UK)Biobank(UKBB).Heritability,genetic overlap,and similarity between hepatic fat content phenotypes were analyzed,and replicated in 10,398 participants from the University Medical Center Groningen(UMCG)Genetics Lifelines Initiative(UGLI).Meta-analysis of GWASs of MRI-PDFF in UKBB revealed five statistically significant loci,including two novel genomic loci harboring CREB3L1(rs72910057-T,P=5.40E−09)and GCM1(rs1491489378-T,P=3.16E−09),respectively,as well as three previously reported loci:PNPLA3,TM6SF2,and APOE.GWAS of FLI in UKBB identified 196 genome-wide significant loci,of which 49 were replicated in UGLI,with top signals in ZPR1(P=3.35E−13)and FTO(P=2.11E−09).Statistically significant genetic correlation(rg)between MRI-PDFF(UKBB)and FLI(UGLI)GWAS results was found(rg=0.5276,P=1.45E−03).Novel MRI-PDFF genetic signals(CREB3L1 and GCM1)were replicated in the FLI GWAS.We identified two novel genes for MRI-PDFF and 49 replicable loci for FLI.Despite a difference in hepatic fat content assessment between MRI-PDFF and FLI,a substantial similar genetic architecture was found.FLI is identified as an easy and reliable approach to study hepatic fat content at the population level.
文摘Metabolic dysfunction associated steatohepatitis(MASH)is a silent epidemic,hiding in the shadows of obesity,and often silently advancing towards the grave complication of cirrhosis.The distinction between MASH and simple hepatic steatosis,which is under the spectrum of metabolic dysfunction-associated steatotic liver disease(MASLD),is highly desired as it provides critical information about the prognosis of the patient.Noninvasive indicators,such as fibrosis-4(FIB-4)index and nonalcoholic fatty liver disease(NAFLD)fibrosis score that includes conventional laboratory data and clinical parameters.
基金National Natural Science Foundation of China(grant Nos.81870404 and 82100648)Natural Science Foundation of Guangdong Province,China(grant Nos.2021A1515011442 and 2022A1515012369)China Postdoctoral Science Foundation(grant No.2020M683128).
文摘Background:High liver fat content(LFC)induces increased risks of both hepatic and extrahepatic progression in metabolic dysfunction-associated steatotic liver disease(MASLD),while maintaining a significant decline in magnetic resonance imaging-based proton density fat fraction(MRI-PDFF)(≥30%decline relative to baseline)without worsening fibrosis results in improved histological severity and prognosis.However,the factors associated with the loss of sustained responses to treatment remain unclear,and we aim to identify them.Methods:Consecutive treatment-naïve MASLD patients between January 2015 and February 2022,with follow-up until April 2023,were included in this prospective cohort study.LFC quantified by MRI-PDFF and liver stiffness measurements(LSM)determined by two-dimensional shear wave elastography(2D-SWE)were evaluated at weeks 0,24 and 48.MRI-PDFF response was defined as a≥30%relative decline in PDFF values,and LSM response was defined as a≥1 stage decline from baseline.Results:A total of 602 MASLD patients were enrolled.Of the 303 patients with a 24-week MRI-PDFF response and complete follow-up of 48 weeks,the rate of loss of MRI-PDFF response was 29.4%,and multivariable logistic regression analyses showed that 24-week insulin resistance(IR),still regular exercise and caloric restriction after 24 weeks,and the relative decline in LFC were risk factors for loss of MRI-PDFF response.Loss of LSM response at 48 weeks occurred in 15.9%of patients,and multivariable analysis confirmed 24-week serum total bile acid(TBA)levels and the relative decline in TBA from baseline as independent predictors.No significant association was found at 48 weeks between loss of MRI-PDFF response and loss of LSM response.Conclusions:MASLD patients with IR and high TBA levels are at higher risks of subsequent diminished sustained improvements of steatosis and fibrosis,respectively.
文摘The application of laser pulses with psec or shorter duration enables nonthermal efficient ultrahigh acceleration of plasma blocks with homogeneous high ion energies exceeding ion current densities of 10^(12) A cm^(-2). The effects of ultrahigh acceleration of plasma blocks with high energy proton beams are proposed for muon production in a compact magnetic fusion device. The proposed new scheme consists of an ignition fusion spark by muon catalyzed fusion(μCF) in a small mirror-like configuration where low temperature D–T plasma is trapped for a duration of 1 μs. This initial fusion spark produces sufficient alpha heating in order to initiate the fusion process in the main device. The use of a multi-fluid global particle and energy balance code allows us to follow the temporal evolution of the reaction rate of the fusion process in the device. Recent progress on the ICAN and IZEST projects for high efficient high power and high repetition rate laser systems allows development of the proposed device for clean energy production. With the proposed approaches,experiments on fusion nuclear reactions and μCF process can be performed in magnetized plasmas in existing kJ/PW laser facilities as the GEKKO-LFEX, the PETAL and the ORION or in the near future laser facilities as the ELI-NP Romanian pillar.
基金carried out at the expense of the Russian Science Foundation grant 25-22-00066, https://rscf.ru/en/project/25-22-00066/
文摘A model for the nuclear medium modification of parton densities is presented.The approach is based on a global analysis of available deep inelastic scattering data for different nuclear targets within the rescaling model,combined with the effects of Fermi motion.The scale dependence is implemented through the DGLAP-evolved quark and gluon densities in a proton derived analytically at the leading order of QCD coupling.By fitting the rescaling parameters to experimental data on the ratio F^(2)^(A)(x,Q^(2))/F_(2)^(A′)(x,Q^(2))for several nuclear targets A and A',we obtain predictions for nuclear parton distributions,even for unmeasured nuclei.The effects of nuclear modifications are investigated with respect to the mass number A.We highlight distinct shadowing and antishadowing behaviors for gluons and quarks.
