1 Results Polymer electrolyte fuel cells (PEFCs) have beenintensively developedfor future vehicle applications andon-site power generation owing to its high energy efficiency and high power density.In PEFCs ,appropria...1 Results Polymer electrolyte fuel cells (PEFCs) have beenintensively developedfor future vehicle applications andon-site power generation owing to its high energy efficiency and high power density.In PEFCs ,appropriatewater management to maintain polymer electrolyte membrane (PEM) hydratedis of great i mportance ,becausethe ion conductivity of membraneislower at lower water content .Consequently,it is of great interest to watercontent and water transport process in PEMs during fuel cell operation.展开更多
目的:基于MRI定量非对称回波最小二乘估算水脂分离(iterative decomposition of water and fat with echo asymmetry and least-squares estimation image quantitation,IDEAL-IQ)技术探讨成年人腰椎不同节段骨髓脂肪与年龄和性别的关...目的:基于MRI定量非对称回波最小二乘估算水脂分离(iterative decomposition of water and fat with echo asymmetry and least-squares estimation image quantitation,IDEAL-IQ)技术探讨成年人腰椎不同节段骨髓脂肪与年龄和性别的关系。方法:收集298例受检者的MRI IDEAL-IQ脂肪分数图像,其中男性138例,女性160例,年龄20~69岁。将所有患者按照每10岁为一个年龄段分为5组:20~29岁(20~组),男24例,女20例;30~39岁(30~组),男47例,女39例;40~49岁(40~组),男36例,女47例;50~59岁(50~组),男20例,女37例;60~69岁(60~组),男11例,女17例。使用脂肪分数图在GE ADW4.6工作站测量L1~L5的骨髓质子密度脂肪分数(proton density fat fraction,PDFF)。结果:同一年龄组、不同性别间PDFF存在差异,20~、30~、40~组人群中,男性L1~L5椎体PDFF均高于女性(P<0.05);50~组人群中男性L1~L5椎体PDFF与女性的差异无统计学意义(P>0.05);60~组人群,男性L1~L5椎体PDFF均低于女性(P<0.05)。腰椎椎体PDFF与年龄呈正相关,女性(r=0.72,P<0.05)相关性高于男性(r=0.32,P<0.05)。从20~69岁,男性L4 PDFF增长率最大(21.08%),女性L1 PDFF增长率最大(65.68%);男性各椎体PDFF增长主要集中在30~及50~组,其中L1、L4、L5椎体PDFF在50~组增长率最大,L2、L3椎体PDFF在30~岁组增长率最大;女性各椎体PDFF在30~组呈轻微下降趋势,此后各椎体PDFF逐渐升高,增长主要集中在40~、50~、60~三个年龄组,其中50~组增长率最大。结论:成人不同年龄组男女性各椎体脂肪分布存在差异,椎体PDFF增长率也有所不同;腰椎不同节段椎体PDFF均与年龄呈正相关。展开更多
目的 探讨非对称回波最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetrical and least-squares estimation quantitation sequence, IDEAL-IQ)来源的R2^(*)值在乳腺良恶性肿瘤鉴别诊断中...目的 探讨非对称回波最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetrical and least-squares estimation quantitation sequence, IDEAL-IQ)来源的R2^(*)值在乳腺良恶性肿瘤鉴别诊断中的价值,并与传统多回波T2^(*)梯度回波(gradient recalled echo, GRE)序列来源的R2^(*)值进行比较。材料与方法 回顾性分析2021年9月至2023年10月在中国医科大学附属第一医院连续收治的42名患者的50个良性肿瘤病灶,在本院影像归档和通信系统(picture archiving and communication systems, PACS)中使用倾向性评分匹配方法匹配肿瘤所在最大层面的最长径,按1∶3的比例纳入150名患者的150个恶性肿瘤病灶。将恶性肿瘤根据预后因子[雌激素受体(estrogen receptor, ER)、孕激素受体(progesterone receptor, PR)以及人表皮生长因子受体2(human epidermal growth factor receptor 2, HER-2)]的阳性/阴性表达情况进行分组。所有患者均接受包含IDEAL-IQ和多回波T2*GRE序列的多参数MRI,测量以下定量参数:IDEAL-IQ序列R2^(*)值(R2^(*)IDEAL)、多回波T2*GRE序列R2^(*)值(R2^(*)GRE)、表观扩散系数(apparent diffusion coefficient, ADC)及肿瘤长径。根据原始资料类型的不同,分别利用单因素分析(独立样本t检验、Mann-Whitney U检验等方法)对比分析各参数的差异。采用Spearman相关性分析R2^(*)IDEAL与R2^(*)GRE及二者与ADC的相关性。采用配对样本t检验比较R2^(*)IDEAL与R2^(*)GRE的差异。采用logistic回归分析建立联合诊断模型,并使用受试者工作特征(receiver operating characteristic, ROC)曲线及曲线下面积(area under the curve,AUC)分析单独及联合参数鉴别乳腺肿瘤良恶性的效能。结果 相关性分析显示乳腺肿瘤患者的R2^(*)IDEAL与R2^(*)GRE呈中度相关(r=0.763,P<0.001),二者与ADC值均呈负性弱相关[r=-0.300(R2^(*)IDEAL),-0.306(R2^(*)GRE),P<0.001]。良性组与恶性组中,R2^(*)IDEAL与R2^(*)GRE均呈中度相关(r=0.745、0.680,P<0.001),二者与ADC均无相关性。两种序列所得的R2^(*)值差异有统计学意义(P<0.001)。R2^(*)IDEAL在良恶性组间差异有统计学意义(P<0.001),管腔HER-2阴性型R2^(*)值最高。对于单一参数,ADC值鉴别良恶性的AUC最高(0.857);对于联合参数,R2^(*)IDEAL+ADC鉴别良性组与管腔阴性组的AUC最高(0.927);差异均有统计学意义(P<0.05)。结论 IDEAL-IQ序列生成的R2^(*)值可用于区分良恶性乳腺肿块,可能成为除ADC外辅助乳腺肿瘤良恶性鉴别的又一无需对比剂参数。展开更多
Magnetic resonance imaging(MRI)is a promising non-invasive method to assess cartilage regeneration based on the quantitative relationship between MRI features and concentrations of the major components in the extracel...Magnetic resonance imaging(MRI)is a promising non-invasive method to assess cartilage regeneration based on the quantitative relationship between MRI features and concentrations of the major components in the extracellular matrix(ECM).To this end,in vitro experiments are performed to investigate the relationship and reveal the underlying mechanism.A series of collagen(COL)and glycosaminoglycan(GAG)solutions at different concentrations are prepared,and T_(1)and T_(2)relaxation times are measured with or without a contrast agent(Gd-DTPA2−)by MRI.Fourier transform infrared spectrometry is also used to measure the contents of biomacromolecule-bound water and other water,allowing theoretical derivation of the relationship between biomacromolecules and the resulting T_(2)values.It has been revealed that the MRI signal in the biomacromolecule aqueous systems is mainly influenced by the protons in hydrogens of biomacromolecule-bound water,which we divide into inner-bound water and outer-bound water.We have also found that COL results in higher sensitivity of bound water than GAG in T_(2)mapping.Owing to the charge effect,GAG regulates the penetration of the contrast agent during dialysis and has a more significant effect on T_(1)values than COL.Considering that COL and GAG are the most abundant biomacromolecules in the cartilage,this study is particularly useful for the real-time MRI-guided assessment of cartilage regeneration.A clinical case is reported as an in vivo demonstration,which is consistent with our in vitro results.The established quantitative relation plays a critical academic role in establishing an international standard ISO/TS24560-1:2022‘Clinical evaluation of regenerative knee articular cartilage using delayed gadolinium-enhanced MRI of cartilage(dGEMRIC)and T_(2)mapping’drafted by us and approved by International Standard Organization.展开更多
目的:探索磁共振成像多点非对称回波采集与迭代最小二乘法水脂分离(iterative decomposition of water and fat with echo asymmetry and the least squares estimation quantification sequence,IDEAL-IQ)和体素内不相干运动(intravoxe...目的:探索磁共振成像多点非对称回波采集与迭代最小二乘法水脂分离(iterative decomposition of water and fat with echo asymmetry and the least squares estimation quantification sequence,IDEAL-IQ)和体素内不相干运动(intravoxel incoherent motion,IVIM)在子宫内膜癌(endometrial carcinoma,EC)细胞增殖状态评估中的价值。方法:回顾并分析24例Ki-67增殖指数低(≤50%)和19例Ki-67增殖指数高(>50%)的EC患者的资料,分别测量病灶IDEAL-IQ成像的脂肪分数(fat fraction,FF)、R_(2)^(*)弛豫率(R_(2)^(*))值和IVIM成像的慢速表观弥散系数(slow apparent diffusion coefficient,ADCslow)、快速表观弥散系数(fast apparent diffusion coefficient,ADC-fast)和灌注分数(perfusion fraction,f)并进行对比。受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under curve,AUC)被用于确定各参数的诊断效能,logistic回归和DeLong检验分别被用于多参数联合诊断和不同AUC间的差异分析。Spearman相关被用于评估各参数值与Ki-67增殖指数的相关性。结果:Ki-67增殖指数高的组ADC-slow、ADC-fast和R_(2)^(*)值均显著低于Ki-67增殖指数低的组(P分别为<0.001、0.004、<0.001)。ADC-slow、ADC-fast、R_(2)^(*)以及三者联合鉴别Ki-67增殖指数高、低组EC的AUC分别为0.860、0.748、0.862和0.978。DeLong分析显示,ADC-slow+ADC-fast+R_(2)^(*)与ADC-slow、ADC-fast及R_(2)^(*)之间的AUC差异均有统计学意义(Z分别为2.109、3.134、2.227;P分别为0.035、0.002、0.023)。ADC-slow和R_(2)^(*)值均与Ki-67增殖指数呈中度负相关(r分别为-0.547、-0.711,P<0.001),ADC-fast与Ki-67增殖指数呈轻度负相关(r分别为-0.324,P=0.034)。结论:ADC-slow、ADC-fast和R_(2)^(*)均有助于评估EC患者的细胞增殖状态,且三者联合能够对Ki-67增殖指数高、低组EC进行更有效的鉴别。展开更多
文摘1 Results Polymer electrolyte fuel cells (PEFCs) have beenintensively developedfor future vehicle applications andon-site power generation owing to its high energy efficiency and high power density.In PEFCs ,appropriatewater management to maintain polymer electrolyte membrane (PEM) hydratedis of great i mportance ,becausethe ion conductivity of membraneislower at lower water content .Consequently,it is of great interest to watercontent and water transport process in PEMs during fuel cell operation.
文摘目的:基于MRI定量非对称回波最小二乘估算水脂分离(iterative decomposition of water and fat with echo asymmetry and least-squares estimation image quantitation,IDEAL-IQ)技术探讨成年人腰椎不同节段骨髓脂肪与年龄和性别的关系。方法:收集298例受检者的MRI IDEAL-IQ脂肪分数图像,其中男性138例,女性160例,年龄20~69岁。将所有患者按照每10岁为一个年龄段分为5组:20~29岁(20~组),男24例,女20例;30~39岁(30~组),男47例,女39例;40~49岁(40~组),男36例,女47例;50~59岁(50~组),男20例,女37例;60~69岁(60~组),男11例,女17例。使用脂肪分数图在GE ADW4.6工作站测量L1~L5的骨髓质子密度脂肪分数(proton density fat fraction,PDFF)。结果:同一年龄组、不同性别间PDFF存在差异,20~、30~、40~组人群中,男性L1~L5椎体PDFF均高于女性(P<0.05);50~组人群中男性L1~L5椎体PDFF与女性的差异无统计学意义(P>0.05);60~组人群,男性L1~L5椎体PDFF均低于女性(P<0.05)。腰椎椎体PDFF与年龄呈正相关,女性(r=0.72,P<0.05)相关性高于男性(r=0.32,P<0.05)。从20~69岁,男性L4 PDFF增长率最大(21.08%),女性L1 PDFF增长率最大(65.68%);男性各椎体PDFF增长主要集中在30~及50~组,其中L1、L4、L5椎体PDFF在50~组增长率最大,L2、L3椎体PDFF在30~岁组增长率最大;女性各椎体PDFF在30~组呈轻微下降趋势,此后各椎体PDFF逐渐升高,增长主要集中在40~、50~、60~三个年龄组,其中50~组增长率最大。结论:成人不同年龄组男女性各椎体脂肪分布存在差异,椎体PDFF增长率也有所不同;腰椎不同节段椎体PDFF均与年龄呈正相关。
基金supported by National Natural Science Foundation of China(grant no.52130302).W。
文摘Magnetic resonance imaging(MRI)is a promising non-invasive method to assess cartilage regeneration based on the quantitative relationship between MRI features and concentrations of the major components in the extracellular matrix(ECM).To this end,in vitro experiments are performed to investigate the relationship and reveal the underlying mechanism.A series of collagen(COL)and glycosaminoglycan(GAG)solutions at different concentrations are prepared,and T_(1)and T_(2)relaxation times are measured with or without a contrast agent(Gd-DTPA2−)by MRI.Fourier transform infrared spectrometry is also used to measure the contents of biomacromolecule-bound water and other water,allowing theoretical derivation of the relationship between biomacromolecules and the resulting T_(2)values.It has been revealed that the MRI signal in the biomacromolecule aqueous systems is mainly influenced by the protons in hydrogens of biomacromolecule-bound water,which we divide into inner-bound water and outer-bound water.We have also found that COL results in higher sensitivity of bound water than GAG in T_(2)mapping.Owing to the charge effect,GAG regulates the penetration of the contrast agent during dialysis and has a more significant effect on T_(1)values than COL.Considering that COL and GAG are the most abundant biomacromolecules in the cartilage,this study is particularly useful for the real-time MRI-guided assessment of cartilage regeneration.A clinical case is reported as an in vivo demonstration,which is consistent with our in vitro results.The established quantitative relation plays a critical academic role in establishing an international standard ISO/TS24560-1:2022‘Clinical evaluation of regenerative knee articular cartilage using delayed gadolinium-enhanced MRI of cartilage(dGEMRIC)and T_(2)mapping’drafted by us and approved by International Standard Organization.
文摘目的:探索磁共振成像多点非对称回波采集与迭代最小二乘法水脂分离(iterative decomposition of water and fat with echo asymmetry and the least squares estimation quantification sequence,IDEAL-IQ)和体素内不相干运动(intravoxel incoherent motion,IVIM)在子宫内膜癌(endometrial carcinoma,EC)细胞增殖状态评估中的价值。方法:回顾并分析24例Ki-67增殖指数低(≤50%)和19例Ki-67增殖指数高(>50%)的EC患者的资料,分别测量病灶IDEAL-IQ成像的脂肪分数(fat fraction,FF)、R_(2)^(*)弛豫率(R_(2)^(*))值和IVIM成像的慢速表观弥散系数(slow apparent diffusion coefficient,ADCslow)、快速表观弥散系数(fast apparent diffusion coefficient,ADC-fast)和灌注分数(perfusion fraction,f)并进行对比。受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under curve,AUC)被用于确定各参数的诊断效能,logistic回归和DeLong检验分别被用于多参数联合诊断和不同AUC间的差异分析。Spearman相关被用于评估各参数值与Ki-67增殖指数的相关性。结果:Ki-67增殖指数高的组ADC-slow、ADC-fast和R_(2)^(*)值均显著低于Ki-67增殖指数低的组(P分别为<0.001、0.004、<0.001)。ADC-slow、ADC-fast、R_(2)^(*)以及三者联合鉴别Ki-67增殖指数高、低组EC的AUC分别为0.860、0.748、0.862和0.978。DeLong分析显示,ADC-slow+ADC-fast+R_(2)^(*)与ADC-slow、ADC-fast及R_(2)^(*)之间的AUC差异均有统计学意义(Z分别为2.109、3.134、2.227;P分别为0.035、0.002、0.023)。ADC-slow和R_(2)^(*)值均与Ki-67增殖指数呈中度负相关(r分别为-0.547、-0.711,P<0.001),ADC-fast与Ki-67增殖指数呈轻度负相关(r分别为-0.324,P=0.034)。结论:ADC-slow、ADC-fast和R_(2)^(*)均有助于评估EC患者的细胞增殖状态,且三者联合能够对Ki-67增殖指数高、低组EC进行更有效的鉴别。
