Amide proton transfer (APT) magnetic resonance imaging (MRI) is an important molecularimaging technique at the protein level in tissue. Neurodegenerative diseases have a highlikelihood of causing abnormal protein accu...Amide proton transfer (APT) magnetic resonance imaging (MRI) is an important molecularimaging technique at the protein level in tissue. Neurodegenerative diseases have a highlikelihood of causing abnormal protein accumulation in the brain, which can be detectedby APT MRI. This article briefly introduces the principles and image processing technologyof APT MRI, and reviews the current state of research on Alzheimer's disease and Parkinson's disease using this technique. Early applications of this approach in these twoneurodegenerative diseases are encouraging, which also suggests continued technicaldevelopment and larger clinical trials to gauge the value of this technique.展开更多
The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch-McConnell equations describing the behavior of magnetization in magnetic resonance imaging (MRI) in the presen...The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch-McConnell equations describing the behavior of magnetization in magnetic resonance imaging (MRI) in the presence of multiple chemical exchange pools. First, the time-dependent Bloch- McConnell equations were reduced to a homogeneous linear differential equation, and then a simple equation was derived to solve it using a matrix operation and Kronecker tensor product. From these solutions, the longitudinal relaxation rate (R1ρ) and transverse relaxation rate in the rotating frame (R2ρ) and Z-spectra were obtained. As illustrative examples, the numerical solutions for linear and star-type three-pool chemical exchange models and linear, star- type, and kite-type four-pool chemical exchange models were presented. The effects of saturation time (ST) and radiofrequency irradiation power (ω1) on the chemical exchange saturation transfer (CEST) effect in these models were also investigated. Although R1ρ and R2ρ were not affected by the ST, the CEST effect observed in the Z-spectra increased and saturated with increasing ST. When ω1 was varied, the CEST effect increased with increasing ω1 in R1ρ, R2ρ, and Z-spectra. When ω1 was large, however, the spillover effect due to the direct saturation of bulk water protons also increased, suggesting that these parameters must be determined in consideration of both the CEST and spillover effects. Our method will be useful for analyzing the complex CEST contrast mechanism and for investigating the optimal conditions for CEST MRI in the presence of multiple chemical exchange pools.展开更多
Background：Amide proton transfer （APT） imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging （MRI） in the field of molecular and cellular imaging.The aim of this study was...Background：Amide proton transfer （APT） imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging （MRI） in the field of molecular and cellular imaging.The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer＆#39;s disease （AD） at 3.0 Tesla.Methods：Twenty AD patients （9 men and 11 women; age range,67-83 years） and 20 age-matched normal controls （11 men and 9 women; age range,63-82 years） underwent APT and traditional MRI examination on a 3.0 Tesla MRI system.The magnetic resonance ratio asymmetry （MTRasym） values at 3.5 ppm of bilateral hippocampi （Hc）,temporal white matter regions,occipital white matter regions,and cerebral peduncles were measured on oblique axial APT images.MTRasym （3.5 ppm） values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test.Controlling for age,partial correlation analysis was used to investigate the associations between mini-mental state examination （MMSE） and the various MRI measures among AD patients.Results：Compared with normal controls,MTRasym （3.5 ppm） values of bilateral Hc were significantly increased in AD patients （right 1.24% ± 0.21% vs.0.83% ± 0.19%,left 1.18% ± 0.18% vs.0.80%± 0.17%,t =3.039,3.328,P =0.004,0.002,respectively）.MTRasym （3.5 ppm） values of bilateral Hc were significantly negatively correlated with MMSE （right r =-0.559,P =0.013; left r=-0.461,P =0.047）.Conclusions：Increased MTRasym （3.5 ppm） values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.展开更多
目的探讨酰胺质子转移加权成像(amide proton transfer weighted imaging,APTw)的影像组学术前预测宫颈癌淋巴血管间隙侵犯(lymphovascular space invasion,LVSI)的价值。材料与方法回顾性分析经手术病理证实的宫颈癌患者病例及影像资...目的探讨酰胺质子转移加权成像(amide proton transfer weighted imaging,APTw)的影像组学术前预测宫颈癌淋巴血管间隙侵犯(lymphovascular space invasion,LVSI)的价值。材料与方法回顾性分析经手术病理证实的宫颈癌患者病例及影像资料66例。所有患者均行盆腔3.0 T MRI检查,包括轴位T2WI、矢状位T2WI、动态对比增强磁共振成像(dynamic contrast enhanced magnetic resonance imaging,DCE-MRI)和3D-APTw序列扫描。在APTw-T2WI融合图像上对肿瘤实质区域进行感兴趣区(region of interest,ROI)勾画并记录APT值。在APT重建图像上进行肿瘤病灶分割并提取影像组学特征。采用组内相关系数(intra-class correlation coefficient,ICC)选取观察者内和观察者间复测信度好的影像组学特征(ICC>0.900)。采用递归特征消除法(recursive feature elimination,RFE)及最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)算法进行特征降维和筛选。基于logistic回归分类器构建临床模型、APTw影像组学模型和联合组学模型。采用受试者工作特征(receiver operating characteristic,ROC)曲线和决策曲线分析(decision curve analysis,DCA)评估模型的诊断效能和临床价值,采用DeLong检验比较不同模型的预测效能。结果在训练集中,APTw影像组学模型预测宫颈癌LVSI的效能高于临床模型(AUC=0.826 vs.0.675),差异有统计学意义(DeLong检验P<0.05)。联合组学模型在训练集和测试集中的AUC值分别为0.838和0.825。DeLong检验结果显示,联合组学模型在训练集中术前评估LVSI的效能显著高于临床模型和APTw影像组学模型(P均<0.05)。决策曲线显示APTw影像组学模型和联合组学模型在训练集和测试集中均具有较高的临床价值。结论基于APTw的影像组学模型在术前预测宫颈癌LVSI方面具有较高的潜力,联合临床因素能进一步提高预测效能,有望为宫颈癌患者的个体化治疗和预后评估提供重要的支持。展开更多
目的探讨酰胺质子转移加权(amide proton transfer weighted,APTw)与动态对比增强磁共振成像(dynamic contrast enhanced MRI,DCE-MRI)序列评估宫颈癌神经周围侵犯(perineural invasion,PNI)的价值。材料与方法回顾性分析36例行盆腔3.0 ...目的探讨酰胺质子转移加权(amide proton transfer weighted,APTw)与动态对比增强磁共振成像(dynamic contrast enhanced MRI,DCE-MRI)序列评估宫颈癌神经周围侵犯(perineural invasion,PNI)的价值。材料与方法回顾性分析36例行盆腔3.0 T MRI检查(包括APTw、DCE-MRI序列)且手术病理证实为宫颈癌的患者病例及影像资料,其中有PNI(PNI组)12例,无PNI(NPNI组)24例。由两位观察者分别测量病灶的APT值与DCE-MRI定量参数值,包括容积转移分数(volume transfer constant,K^(trans))、速率常数(exchange rate between EES and blood plasma,K_(ep))、血管外细胞外间隙容积分数(extravascular volume fraction,V_(e))以及血浆容积分数(capillary plasma volume,V_(p))。采用组内相关系数(intra-class correlation coefficient,ICC)检验2位观察者对各参数值测量结果的一致性;采用Kolmogorov-Smirov检验数据是否符合正态分布,通过两独立样本t检验或Mann-Whitney U检验比较两组间参数值的差异,采用受试者工作特征(receiver Operating Characteristic,ROC)曲线评估有差异参数诊断PNI效能,获得相应的曲线下面积(area under the curve,AUC)、阈值、敏感度和特异度。采用二元logistic回归计算有差异参数的联合诊断效能,DeLong检验进行各参数和联合参数AUC比较,Spearman相关分析检测APT值和有差异DCE-MRI参数间的相关性。结果两位观察者测得的APT值及K^(trans)值、K_(ep)值、V_(e)值、V_(p)值结果一致性良好,ICC均>0.75。两组间的APT值和V_(p)值差异有统计学意义(P<0.05),K^(trans)、K_(ep)、V_(e)差异无统计学意义(P>0.05)。PNI组的APT值(2.89%±0.72%)和V_(p)值[7.80×10^(-3)(6.80×10^(-3),1.14×10^(-2))]均大于NPNI组[APT值2.31%±0.71%;V_(p)值4.19×10^(-3)(2.04×10^(-3),7.35×10^(-3))]。评估宫颈癌PNI时,APT值和V_(p)值的AUC分别为0.717、0.785,阈值分别为2.7%及6.46×10^(-3),敏感度及特异度分别为66.7%及75.0%、83.3%及75.0%;APT值联合V_(p)值后的AUC为0.792,APT值、V_(p)值与两者联合后的AUC之间差异无统计学意义(P>0.05)。APT值与V_(p)值无相关性(r=0.219,P=0.198)。结论APTw序列及DCE-MRI的定量参数均能有效预测宫颈癌PNI,具有一定临床应用价值。展开更多
目的对比磁共振酰胺质子转移(Amide Proton Transfer,APT)成像、扩散加权成像(Diffusion Weighted Imaging,DWI)和动态增强(Dynamic Contrast-Enhanced,DCE)成像以及3者联合应用在鉴别乳腺良恶性病变中的诊断价值。方法纳入55例乳腺疾...目的对比磁共振酰胺质子转移(Amide Proton Transfer,APT)成像、扩散加权成像(Diffusion Weighted Imaging,DWI)和动态增强(Dynamic Contrast-Enhanced,DCE)成像以及3者联合应用在鉴别乳腺良恶性病变中的诊断价值。方法纳入55例乳腺疾病患者,均进行APT、DWI以及DCE扫描,测量非对称磁化转移(Magnetization Transfer Asymmetry,MTRasym)率和表观扩散系数(Apparent Diffusion Coefficient,ADC)值,并记录乳腺影像报告和数据系统的分类。分析乳腺良恶性病变各参数之间的差异,使用Logistic回归建立联合诊断模型,采用受试者工作特征曲线(Receive Operating Characteristic,ROC)计算各诊断模型在乳腺良恶性病变中的诊断价值,并比较恶性病变中不同病理因素组间的差异以及各病理因素与APT之间的相关性。结果恶性组中MTRasym和ADC值均小于良性组,差异具有统计学意义(均P<0.05),DWI、APT、DCE以及APT+DCE、APT+DWI、DCE+DWI、DWI+APT+DCE联合模型鉴别乳腺良恶性病变的曲线下面积(Area Under Curve,AUC)分别为0.804、0.723、0.741以及0.782、0.895、0.897、0.970;DWI+APT+DCE联合诊断模型的AUC显著大于DWI、APT、DCE以及任意两者联合诊断模型(均P<0.05)。Ki-67高表达组的MTRasym值较低表达组高[(3.934%±0.883%)v s.(3.192%±0.949%)],乳腺癌浸润程度组织学分级Ⅲ级组的M T R a s y m值较Ⅱ级组高[(4.225%±0.932%)vs.(3.451%±0.873%)],差异均有统计学意义(均P<0.05),并且APT与两者均呈中度正相关(r=0.627、0.537,均P<0.05)。结论APT成像技术在乳腺良恶性病变的鉴别中具有较好的诊断价值,与常规DWI、DCE成像无显著差异,并且三者联合应用的诊断价值更高。展开更多
文摘Amide proton transfer (APT) magnetic resonance imaging (MRI) is an important molecularimaging technique at the protein level in tissue. Neurodegenerative diseases have a highlikelihood of causing abnormal protein accumulation in the brain, which can be detectedby APT MRI. This article briefly introduces the principles and image processing technologyof APT MRI, and reviews the current state of research on Alzheimer's disease and Parkinson's disease using this technique. Early applications of this approach in these twoneurodegenerative diseases are encouraging, which also suggests continued technicaldevelopment and larger clinical trials to gauge the value of this technique.
文摘The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch-McConnell equations describing the behavior of magnetization in magnetic resonance imaging (MRI) in the presence of multiple chemical exchange pools. First, the time-dependent Bloch- McConnell equations were reduced to a homogeneous linear differential equation, and then a simple equation was derived to solve it using a matrix operation and Kronecker tensor product. From these solutions, the longitudinal relaxation rate (R1ρ) and transverse relaxation rate in the rotating frame (R2ρ) and Z-spectra were obtained. As illustrative examples, the numerical solutions for linear and star-type three-pool chemical exchange models and linear, star- type, and kite-type four-pool chemical exchange models were presented. The effects of saturation time (ST) and radiofrequency irradiation power (ω1) on the chemical exchange saturation transfer (CEST) effect in these models were also investigated. Although R1ρ and R2ρ were not affected by the ST, the CEST effect observed in the Z-spectra increased and saturated with increasing ST. When ω1 was varied, the CEST effect increased with increasing ω1 in R1ρ, R2ρ, and Z-spectra. When ω1 was large, however, the spillover effect due to the direct saturation of bulk water protons also increased, suggesting that these parameters must be determined in consideration of both the CEST and spillover effects. Our method will be useful for analyzing the complex CEST contrast mechanism and for investigating the optimal conditions for CEST MRI in the presence of multiple chemical exchange pools.
文摘Background：Amide proton transfer （APT） imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging （MRI） in the field of molecular and cellular imaging.The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer＆#39;s disease （AD） at 3.0 Tesla.Methods：Twenty AD patients （9 men and 11 women; age range,67-83 years） and 20 age-matched normal controls （11 men and 9 women; age range,63-82 years） underwent APT and traditional MRI examination on a 3.0 Tesla MRI system.The magnetic resonance ratio asymmetry （MTRasym） values at 3.5 ppm of bilateral hippocampi （Hc）,temporal white matter regions,occipital white matter regions,and cerebral peduncles were measured on oblique axial APT images.MTRasym （3.5 ppm） values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test.Controlling for age,partial correlation analysis was used to investigate the associations between mini-mental state examination （MMSE） and the various MRI measures among AD patients.Results：Compared with normal controls,MTRasym （3.5 ppm） values of bilateral Hc were significantly increased in AD patients （right 1.24% ± 0.21% vs.0.83% ± 0.19%,left 1.18% ± 0.18% vs.0.80%± 0.17%,t =3.039,3.328,P =0.004,0.002,respectively）.MTRasym （3.5 ppm） values of bilateral Hc were significantly negatively correlated with MMSE （right r =-0.559,P =0.013; left r=-0.461,P =0.047）.Conclusions：Increased MTRasym （3.5 ppm） values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.
文摘目的探讨酰胺质子转移加权成像(amide proton transfer weighted imaging,APTw)的影像组学术前预测宫颈癌淋巴血管间隙侵犯(lymphovascular space invasion,LVSI)的价值。材料与方法回顾性分析经手术病理证实的宫颈癌患者病例及影像资料66例。所有患者均行盆腔3.0 T MRI检查,包括轴位T2WI、矢状位T2WI、动态对比增强磁共振成像(dynamic contrast enhanced magnetic resonance imaging,DCE-MRI)和3D-APTw序列扫描。在APTw-T2WI融合图像上对肿瘤实质区域进行感兴趣区(region of interest,ROI)勾画并记录APT值。在APT重建图像上进行肿瘤病灶分割并提取影像组学特征。采用组内相关系数(intra-class correlation coefficient,ICC)选取观察者内和观察者间复测信度好的影像组学特征(ICC>0.900)。采用递归特征消除法(recursive feature elimination,RFE)及最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)算法进行特征降维和筛选。基于logistic回归分类器构建临床模型、APTw影像组学模型和联合组学模型。采用受试者工作特征(receiver operating characteristic,ROC)曲线和决策曲线分析(decision curve analysis,DCA)评估模型的诊断效能和临床价值,采用DeLong检验比较不同模型的预测效能。结果在训练集中,APTw影像组学模型预测宫颈癌LVSI的效能高于临床模型(AUC=0.826 vs.0.675),差异有统计学意义(DeLong检验P<0.05)。联合组学模型在训练集和测试集中的AUC值分别为0.838和0.825。DeLong检验结果显示,联合组学模型在训练集中术前评估LVSI的效能显著高于临床模型和APTw影像组学模型(P均<0.05)。决策曲线显示APTw影像组学模型和联合组学模型在训练集和测试集中均具有较高的临床价值。结论基于APTw的影像组学模型在术前预测宫颈癌LVSI方面具有较高的潜力,联合临床因素能进一步提高预测效能,有望为宫颈癌患者的个体化治疗和预后评估提供重要的支持。
文摘目的探讨酰胺质子转移加权(amide proton transfer weighted,APTw)与动态对比增强磁共振成像(dynamic contrast enhanced MRI,DCE-MRI)序列评估宫颈癌神经周围侵犯(perineural invasion,PNI)的价值。材料与方法回顾性分析36例行盆腔3.0 T MRI检查(包括APTw、DCE-MRI序列)且手术病理证实为宫颈癌的患者病例及影像资料,其中有PNI(PNI组)12例,无PNI(NPNI组)24例。由两位观察者分别测量病灶的APT值与DCE-MRI定量参数值,包括容积转移分数(volume transfer constant,K^(trans))、速率常数(exchange rate between EES and blood plasma,K_(ep))、血管外细胞外间隙容积分数(extravascular volume fraction,V_(e))以及血浆容积分数(capillary plasma volume,V_(p))。采用组内相关系数(intra-class correlation coefficient,ICC)检验2位观察者对各参数值测量结果的一致性;采用Kolmogorov-Smirov检验数据是否符合正态分布,通过两独立样本t检验或Mann-Whitney U检验比较两组间参数值的差异,采用受试者工作特征(receiver Operating Characteristic,ROC)曲线评估有差异参数诊断PNI效能,获得相应的曲线下面积(area under the curve,AUC)、阈值、敏感度和特异度。采用二元logistic回归计算有差异参数的联合诊断效能,DeLong检验进行各参数和联合参数AUC比较,Spearman相关分析检测APT值和有差异DCE-MRI参数间的相关性。结果两位观察者测得的APT值及K^(trans)值、K_(ep)值、V_(e)值、V_(p)值结果一致性良好,ICC均>0.75。两组间的APT值和V_(p)值差异有统计学意义(P<0.05),K^(trans)、K_(ep)、V_(e)差异无统计学意义(P>0.05)。PNI组的APT值(2.89%±0.72%)和V_(p)值[7.80×10^(-3)(6.80×10^(-3),1.14×10^(-2))]均大于NPNI组[APT值2.31%±0.71%;V_(p)值4.19×10^(-3)(2.04×10^(-3),7.35×10^(-3))]。评估宫颈癌PNI时,APT值和V_(p)值的AUC分别为0.717、0.785,阈值分别为2.7%及6.46×10^(-3),敏感度及特异度分别为66.7%及75.0%、83.3%及75.0%;APT值联合V_(p)值后的AUC为0.792,APT值、V_(p)值与两者联合后的AUC之间差异无统计学意义(P>0.05)。APT值与V_(p)值无相关性(r=0.219,P=0.198)。结论APTw序列及DCE-MRI的定量参数均能有效预测宫颈癌PNI,具有一定临床应用价值。
文摘目的对比磁共振酰胺质子转移(Amide Proton Transfer,APT)成像、扩散加权成像(Diffusion Weighted Imaging,DWI)和动态增强(Dynamic Contrast-Enhanced,DCE)成像以及3者联合应用在鉴别乳腺良恶性病变中的诊断价值。方法纳入55例乳腺疾病患者,均进行APT、DWI以及DCE扫描,测量非对称磁化转移(Magnetization Transfer Asymmetry,MTRasym)率和表观扩散系数(Apparent Diffusion Coefficient,ADC)值,并记录乳腺影像报告和数据系统的分类。分析乳腺良恶性病变各参数之间的差异,使用Logistic回归建立联合诊断模型,采用受试者工作特征曲线(Receive Operating Characteristic,ROC)计算各诊断模型在乳腺良恶性病变中的诊断价值,并比较恶性病变中不同病理因素组间的差异以及各病理因素与APT之间的相关性。结果恶性组中MTRasym和ADC值均小于良性组,差异具有统计学意义(均P<0.05),DWI、APT、DCE以及APT+DCE、APT+DWI、DCE+DWI、DWI+APT+DCE联合模型鉴别乳腺良恶性病变的曲线下面积(Area Under Curve,AUC)分别为0.804、0.723、0.741以及0.782、0.895、0.897、0.970;DWI+APT+DCE联合诊断模型的AUC显著大于DWI、APT、DCE以及任意两者联合诊断模型(均P<0.05)。Ki-67高表达组的MTRasym值较低表达组高[(3.934%±0.883%)v s.(3.192%±0.949%)],乳腺癌浸润程度组织学分级Ⅲ级组的M T R a s y m值较Ⅱ级组高[(4.225%±0.932%)vs.(3.451%±0.873%)],差异均有统计学意义(均P<0.05),并且APT与两者均呈中度正相关(r=0.627、0.537,均P<0.05)。结论APT成像技术在乳腺良恶性病变的鉴别中具有较好的诊断价值,与常规DWI、DCE成像无显著差异,并且三者联合应用的诊断价值更高。
