目的:探讨动态增强磁共振成像(dynamic contrast enhanced magnetic resonance imaging,DCE-MRI)的药代动力学参数[如容量转移常数(volume transfer constant,Ktrans)、血管外细胞外容积分数(extravascular extracellular space distrib...目的:探讨动态增强磁共振成像(dynamic contrast enhanced magnetic resonance imaging,DCE-MRI)的药代动力学参数[如容量转移常数(volume transfer constant,Ktrans)、血管外细胞外容积分数(extravascular extracellular space distribute volume per unit tissue volume,Ve)和返流速率常数(microvascular permeability reflux constant,Kep)]用于肌骨系统肿瘤定性诊断中的可行性。方法:选择2013年10月至2014年9月来北京积水潭医院就诊的肌骨系统肿瘤患者共34例进行回顾性分析,患者使用1.5T MR扫描仪进行检查,DCE-MRI使用脂肪抑制3D VIBE(volumetric interpolated breath-hold exam)序列。根据病理诊断结果,将肿瘤分为良性、交界性及恶性,病灶所在层面的正常肌肉组织作为对照组,对每组肿瘤与对照组的Ktrans、Ve和Kep的差异进行配对t检验,对3组病变数据中的差异进行单因素方差分析,P<0.05认为差异具有统计学意义。结果:良性肿瘤Ktrans和Kep值与对照组的差异无统计学意义,而Ve值与对照组比较有所升高。交界性肿瘤的Ktrans和Ve值明显高于对照组,而Kep与对照组差异无统计学意义(P>0.05)。恶性肿瘤的Ktrans、Kep和Ve值明显高于对照组。恶性肿瘤的Ktrans(P<0.001)和Kep(P<0.01)均高于良性和交界性肿瘤,Ve高于良性肿瘤(P<0.05),而与交界性肿瘤差异无统计学意义(P>0.05)。良性和交界性肿瘤的Ktrans、Kep和Ve值之间的差异无统计学意义(P>0.05)。结论:DCE-MRI药代动力学参数Ktrans和Kep可以反映肌骨系统良性、交界性和恶性肿瘤在毛细血管渗透性方面存在的差异,这将有助于肿瘤的定性诊断。展开更多
目的：比较不同场强磁共振成像（ magnetic resonance imaging ，MRI）设备诊断腰椎间盘退变的价值。方法120例腰椎间盘退变患者的600个椎间盘，分别采用1．5T和3．0T 超导磁共振仪扫描，测得椎间盘表观系数（ apparent diffusion coeff...目的：比较不同场强磁共振成像（ magnetic resonance imaging ，MRI）设备诊断腰椎间盘退变的价值。方法120例腰椎间盘退变患者的600个椎间盘，分别采用1．5T和3．0T 超导磁共振仪扫描，测得椎间盘表观系数（ apparent diffusion coefficient ，ADC）值；依据Pfirrmann标准对腰椎间盘进行分级。结果1．5T MR椎间盘Pfirrmann分级：Ⅰ级31个，Ⅱ级94个，Ⅲ级86个，Ⅳ级78个，Ⅴ级11个；3．0T MR椎间盘Pfirrmann分级：Ⅰ级41个，Ⅱ级80个，Ⅲ级81个，Ⅳ级91个，Ⅴ级7个。不同级别椎间盘ADC值比较，1．5TMR的Ⅳ和Ⅴ级椎间盘ADC值均分别小于Ⅰ、Ⅱ和Ⅲ级，Ⅴ级椎间盘ADC 值明显低于Ⅳ级盘（ P ＜0．05）。3．0TMR组Ⅰ和Ⅱ级盘ADC值差异无统计学意义（ P ＞0．05），其余椎间盘随分级增高，ADC值明显减低（ P ＜0．05）。同一级别椎间盘3．0TMR组ADC值明显低于1．5TMR组（ P ＜0．05）。同水平同级别椎间盘2组MR设备ADC值比较，L1／2的各级椎间盘，3．0TMR组ADC值明显小于1．5TMR（ P ＜0．05）；L2／3的Ⅱ和Ⅲ～Ⅴ级盘3．0 TMR组ADC值明显小于1．5TMR组（ P ＜0．05）；L3／4和L4／5的Ⅲ和Ⅳ～Ⅴ级盘3．0TMR组ADC值明显低于1．5TMR（ P ＜0．05）；L5／S1的Ⅰ～Ⅱ级、Ⅲ级和Ⅳ～Ⅴ级盘3．0TMR组ADC值明显低于1．5TMR组（ P ＜0．05）。结论 MR测得的ADC值可用于腰椎间盘退变评估，椎间盘Pfirrmann分级越高，其对应的ADC值越低；与1．5TMR设备比较，3．0TMR对诊断早期轻度腰椎间盘退变更加敏感。展开更多
The extracellular space(ECS) of brain is defined as an irregular channel which is located in the interstitial tissue outside the plasma membranes of neurons,and occupied by interstititial fluid(ISF).Diffusion in ECS i...The extracellular space(ECS) of brain is defined as an irregular channel which is located in the interstitial tissue outside the plasma membranes of neurons,and occupied by interstititial fluid(ISF).Diffusion in ECS is described by a modified diffusion equation from which several parameters can be calculated,such as the diffusion coefficient(D),the tortuosity(λ),the volume fraction(α) and the clearance of molecules.Radiolabeled tracers were used for early diffusion measurements.Presently,the real-time iontophoresis(RTI) method is employed for small ions,whereas the integrative optical imaging(IOI) and the magnetic resonance diffusion weighted imaging(DWI) are developed for macromolecules tracers.Extensive experimental studies with such methods show that in normal brain tissue,the volume fraction of ECS typically is about 20% and the tortuosity is 1.6,although there are regional variations.These parameters change with the brain development and in various pathophysiological states.Knowledge of ECS diffusion properties help us to understand extrasynaptic volume transmission to the development of paradigms for drug delivery in brain.展开更多
文摘目的:探讨动态增强磁共振成像(dynamic contrast enhanced magnetic resonance imaging,DCE-MRI)的药代动力学参数[如容量转移常数(volume transfer constant,Ktrans)、血管外细胞外容积分数(extravascular extracellular space distribute volume per unit tissue volume,Ve)和返流速率常数(microvascular permeability reflux constant,Kep)]用于肌骨系统肿瘤定性诊断中的可行性。方法:选择2013年10月至2014年9月来北京积水潭医院就诊的肌骨系统肿瘤患者共34例进行回顾性分析,患者使用1.5T MR扫描仪进行检查,DCE-MRI使用脂肪抑制3D VIBE(volumetric interpolated breath-hold exam)序列。根据病理诊断结果,将肿瘤分为良性、交界性及恶性,病灶所在层面的正常肌肉组织作为对照组,对每组肿瘤与对照组的Ktrans、Ve和Kep的差异进行配对t检验,对3组病变数据中的差异进行单因素方差分析,P<0.05认为差异具有统计学意义。结果:良性肿瘤Ktrans和Kep值与对照组的差异无统计学意义,而Ve值与对照组比较有所升高。交界性肿瘤的Ktrans和Ve值明显高于对照组,而Kep与对照组差异无统计学意义(P>0.05)。恶性肿瘤的Ktrans、Kep和Ve值明显高于对照组。恶性肿瘤的Ktrans(P<0.001)和Kep(P<0.01)均高于良性和交界性肿瘤,Ve高于良性肿瘤(P<0.05),而与交界性肿瘤差异无统计学意义(P>0.05)。良性和交界性肿瘤的Ktrans、Kep和Ve值之间的差异无统计学意义(P>0.05)。结论:DCE-MRI药代动力学参数Ktrans和Kep可以反映肌骨系统良性、交界性和恶性肿瘤在毛细血管渗透性方面存在的差异,这将有助于肿瘤的定性诊断。
文摘目的：比较不同场强磁共振成像（ magnetic resonance imaging ，MRI）设备诊断腰椎间盘退变的价值。方法120例腰椎间盘退变患者的600个椎间盘，分别采用1．5T和3．0T 超导磁共振仪扫描，测得椎间盘表观系数（ apparent diffusion coefficient ，ADC）值；依据Pfirrmann标准对腰椎间盘进行分级。结果1．5T MR椎间盘Pfirrmann分级：Ⅰ级31个，Ⅱ级94个，Ⅲ级86个，Ⅳ级78个，Ⅴ级11个；3．0T MR椎间盘Pfirrmann分级：Ⅰ级41个，Ⅱ级80个，Ⅲ级81个，Ⅳ级91个，Ⅴ级7个。不同级别椎间盘ADC值比较，1．5TMR的Ⅳ和Ⅴ级椎间盘ADC值均分别小于Ⅰ、Ⅱ和Ⅲ级，Ⅴ级椎间盘ADC 值明显低于Ⅳ级盘（ P ＜0．05）。3．0TMR组Ⅰ和Ⅱ级盘ADC值差异无统计学意义（ P ＞0．05），其余椎间盘随分级增高，ADC值明显减低（ P ＜0．05）。同一级别椎间盘3．0TMR组ADC值明显低于1．5TMR组（ P ＜0．05）。同水平同级别椎间盘2组MR设备ADC值比较，L1／2的各级椎间盘，3．0TMR组ADC值明显小于1．5TMR（ P ＜0．05）；L2／3的Ⅱ和Ⅲ～Ⅴ级盘3．0 TMR组ADC值明显小于1．5TMR组（ P ＜0．05）；L3／4和L4／5的Ⅲ和Ⅳ～Ⅴ级盘3．0TMR组ADC值明显低于1．5TMR（ P ＜0．05）；L5／S1的Ⅰ～Ⅱ级、Ⅲ级和Ⅳ～Ⅴ级盘3．0TMR组ADC值明显低于1．5TMR组（ P ＜0．05）。结论 MR测得的ADC值可用于腰椎间盘退变评估，椎间盘Pfirrmann分级越高，其对应的ADC值越低；与1．5TMR设备比较，3．0TMR对诊断早期轻度腰椎间盘退变更加敏感。
文摘The extracellular space(ECS) of brain is defined as an irregular channel which is located in the interstitial tissue outside the plasma membranes of neurons,and occupied by interstititial fluid(ISF).Diffusion in ECS is described by a modified diffusion equation from which several parameters can be calculated,such as the diffusion coefficient(D),the tortuosity(λ),the volume fraction(α) and the clearance of molecules.Radiolabeled tracers were used for early diffusion measurements.Presently,the real-time iontophoresis(RTI) method is employed for small ions,whereas the integrative optical imaging(IOI) and the magnetic resonance diffusion weighted imaging(DWI) are developed for macromolecules tracers.Extensive experimental studies with such methods show that in normal brain tissue,the volume fraction of ECS typically is about 20% and the tortuosity is 1.6,although there are regional variations.These parameters change with the brain development and in various pathophysiological states.Knowledge of ECS diffusion properties help us to understand extrasynaptic volume transmission to the development of paradigms for drug delivery in brain.
