Background: Diffusion-tensor (DT) magnetic resonance imaging (MRI) has the po tential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques. Objective: To investigate whether ...Background: Diffusion-tensor (DT) magnetic resonance imaging (MRI) has the po tential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques. Objective: To investigate whether normal-appearing bra in tissue abnormalities occur in patients with multiple sclerosis at the earlies t clinical stage and whether their severity is predictive of a short-term disea se evolution by using DT MRI. Design: Forty-five patients and 22 healthy contro l subjects were studied. All patients had had a clinically isolated syndrome wit hin the 3 months preceding study enrollment and paraclinical evidence of disease dissemination in space. During a single session, dual-echo, pulsed-gradient s pin-echo echo-planar, and postgadolinium T1-weighted images of the brain were obtained from each subject. In patients, dual-echo and enhanced images were ob tained after 3 and 12 months, to detect MRI signs of disease dissemination in ti me. An on-study neurological examination was also conducted to ascertain the oc currence of clinical relapses. Mean diffusivity and fractional anisotropy maps w ere derived from DT images. Normal-appearing white matter (N-AWM) and normal- appearing gray matter mean diffusivity and fractional anisotropy histograms were produced and analyzed. Results: During the study period, 29 patients showed MRI evidence of disease dissemination in time. When compared with healthy controls, patients showed higher average NAWM mean diffusivity (P=.01), lower average NAW M mean diffusivity peak height (P < .001), and fractional anisotropy (P < .001). The DT MRI characteristics of patients did not differ between those with and those without disease dissemina tion in time at follow-up. Conclusions: In patients with multiple sclerosis at the earliest clinical stage, the severity of NAWM damage does not predict new le sion formation in the short term, suggesting that the “diffuse”component of ti ssue damage is, at least partially, independent of the “discrete,”predominantl y inflammatory aspects of the disease since its clinical onset.展开更多
Objectives: We sought to elucidate the effects of 20- mg versus 5- mg atorvastatin on thoracic and abdominal aortic plaques. Background: Regression of thoracic aortic plaques by simvastatin was demonstrated using magn...Objectives: We sought to elucidate the effects of 20- mg versus 5- mg atorvastatin on thoracic and abdominal aortic plaques. Background: Regression of thoracic aortic plaques by simvastatin was demonstrated using magnetic resonance imaging(MRI). However, the effects of different doses of statin have not been assessed. Methods: Using MRI, we investigated the effects of 20- mg versus 5- mg atorvastatin on thoracic and abdominal aortic plaques in 40 hypercholesterolemic patients who were randomized to receive either dose. Treatment effects were evaluated as changes in vessel wall thickness(VWT) and vessel wall area(VWA) of atherosclerotic lesions from baseline to 12 months of treatment. Results: The 20- mg dose induced a greater low- density lipoprotein(LDL) cholesterol reduction than did the 5- mg dose(- 47% vs.- 34% , p< 0.001). Although 20 mg and 5 mg reduced C- reactive protein(CRP) levels(- 47% and- 28% ), the degree of CRP reduction did not differ between the two doses. The 20- mg dose reduced VWT and VWA of thoracic aortic plaques(- 12% and - 18% , p< 0.001), whereas 5 mg did not(+ 1% and + 4% ). Regarding abdominal aortic plaques, even 20 mg could not reduce VWT or VWA(- 1% and + 3% ), but instead progression was observed with 5mg treatment(+ 5% and + 12% , p< 0.01). Notably, the degree of plaque regression in thoracic aorta correlated with LDL cholesterol(r=0.64) and CRP(r=0.49) reductions. Although changes in abdominal aortic plaques only weakly correlated with LDL cholesterol reduction(r=0.34), they correlated with age(r=0.41). Conclusions: One- year 20- mg atorvastatin treatment induced regression of thoracic aortic plaques with marked LDL cholesterol reduction, whereas it resulted in only retardation of plaque progression in abdominal aorta. Thoracic and abdominal aortic plaques may have different susceptibilities to lipid lowering.展开更多
核磁共振成像(Nuclear Magnetic Resonance Imaging,MRI)是利用较强的磁场和无线电波相互作用,通过外加梯度磁场检测后在物质内部不同范围内释放的能量,即可得知构成这一物体原子核的位置和种类,据此可以绘制成物体内部的结构图像。此...核磁共振成像(Nuclear Magnetic Resonance Imaging,MRI)是利用较强的磁场和无线电波相互作用,通过外加梯度磁场检测后在物质内部不同范围内释放的能量,即可得知构成这一物体原子核的位置和种类,据此可以绘制成物体内部的结构图像。此项技术在临床诊断、科学研究的应用成为现实,MRI的技术应用在医学、神经学、生理学的诊断和治疗方面起到至关重要的作用。MRI具有高分辨率、无创以及可重复检查等优点,能够非常好的区分动脉粥样硬化斑块的组成成分和形态学特征。而现如今,应用MRI技术临床的研究热门话题是对易损斑块进行筛查和性质评估。文章对MRI检测易损斑块的优势与不足进行综述。展开更多
Objective: To establish an orthotopic bladder cancer model bearing human bladder cancer for experimental research, and monitor tumor progression by magnetic resonance imaging (MRI). Methods: The mucosa was mechanicall...Objective: To establish an orthotopic bladder cancer model bearing human bladder cancer for experimental research, and monitor tumor progression by magnetic resonance imaging (MRI). Methods: The mucosa was mechanically damaged transurethrally under direct vision, and then human bladder cancer cell line T24 was inoculated into the bladders of BALB/c nude mice to establish orthotopic bladder cancer model. To find a suitable concentration of Gd-DTPA for this re- search. MRI was performed weekly to assess tumor growth, using Gd-DTPA as contrast agent. The pathologic morphology of the bladders and other specimens were observed with HE stain. Results: All the 25 mice developed bladder cancer after inoculation. The best concentration of Gd-DTPA was 1.408 mg/mL. On MRI, no change in the bladders was observed on day 7 after inoculation, filling defect in the bladders, accordant to actual tumor size, was detected on days 14, 21 and 28. Pathologic examination showed that tumor grew in the mucosa or superficial muscle of bladder on day 7, confined in muscle layer on days 14–28, and invaded serosa on day 35. Conclusion: Transurethrally damaged bladder mucosa under direct vision and instilled bladder cancer cell T24, we successfully established an orthotopic bladder cancer model. Tumor growth simulated the progression of human bladder cancer approximately. MRI was a reliable way for dynamic detection of murine orthotopic bladder tumor.展开更多
文摘Background: Diffusion-tensor (DT) magnetic resonance imaging (MRI) has the po tential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques. Objective: To investigate whether normal-appearing bra in tissue abnormalities occur in patients with multiple sclerosis at the earlies t clinical stage and whether their severity is predictive of a short-term disea se evolution by using DT MRI. Design: Forty-five patients and 22 healthy contro l subjects were studied. All patients had had a clinically isolated syndrome wit hin the 3 months preceding study enrollment and paraclinical evidence of disease dissemination in space. During a single session, dual-echo, pulsed-gradient s pin-echo echo-planar, and postgadolinium T1-weighted images of the brain were obtained from each subject. In patients, dual-echo and enhanced images were ob tained after 3 and 12 months, to detect MRI signs of disease dissemination in ti me. An on-study neurological examination was also conducted to ascertain the oc currence of clinical relapses. Mean diffusivity and fractional anisotropy maps w ere derived from DT images. Normal-appearing white matter (N-AWM) and normal- appearing gray matter mean diffusivity and fractional anisotropy histograms were produced and analyzed. Results: During the study period, 29 patients showed MRI evidence of disease dissemination in time. When compared with healthy controls, patients showed higher average NAWM mean diffusivity (P=.01), lower average NAW M mean diffusivity peak height (P < .001), and fractional anisotropy (P < .001). The DT MRI characteristics of patients did not differ between those with and those without disease dissemina tion in time at follow-up. Conclusions: In patients with multiple sclerosis at the earliest clinical stage, the severity of NAWM damage does not predict new le sion formation in the short term, suggesting that the “diffuse”component of ti ssue damage is, at least partially, independent of the “discrete,”predominantl y inflammatory aspects of the disease since its clinical onset.
文摘Objectives: We sought to elucidate the effects of 20- mg versus 5- mg atorvastatin on thoracic and abdominal aortic plaques. Background: Regression of thoracic aortic plaques by simvastatin was demonstrated using magnetic resonance imaging(MRI). However, the effects of different doses of statin have not been assessed. Methods: Using MRI, we investigated the effects of 20- mg versus 5- mg atorvastatin on thoracic and abdominal aortic plaques in 40 hypercholesterolemic patients who were randomized to receive either dose. Treatment effects were evaluated as changes in vessel wall thickness(VWT) and vessel wall area(VWA) of atherosclerotic lesions from baseline to 12 months of treatment. Results: The 20- mg dose induced a greater low- density lipoprotein(LDL) cholesterol reduction than did the 5- mg dose(- 47% vs.- 34% , p< 0.001). Although 20 mg and 5 mg reduced C- reactive protein(CRP) levels(- 47% and- 28% ), the degree of CRP reduction did not differ between the two doses. The 20- mg dose reduced VWT and VWA of thoracic aortic plaques(- 12% and - 18% , p< 0.001), whereas 5 mg did not(+ 1% and + 4% ). Regarding abdominal aortic plaques, even 20 mg could not reduce VWT or VWA(- 1% and + 3% ), but instead progression was observed with 5mg treatment(+ 5% and + 12% , p< 0.01). Notably, the degree of plaque regression in thoracic aorta correlated with LDL cholesterol(r=0.64) and CRP(r=0.49) reductions. Although changes in abdominal aortic plaques only weakly correlated with LDL cholesterol reduction(r=0.34), they correlated with age(r=0.41). Conclusions: One- year 20- mg atorvastatin treatment induced regression of thoracic aortic plaques with marked LDL cholesterol reduction, whereas it resulted in only retardation of plaque progression in abdominal aorta. Thoracic and abdominal aortic plaques may have different susceptibilities to lipid lowering.
文摘核磁共振成像(Nuclear Magnetic Resonance Imaging,MRI)是利用较强的磁场和无线电波相互作用,通过外加梯度磁场检测后在物质内部不同范围内释放的能量,即可得知构成这一物体原子核的位置和种类,据此可以绘制成物体内部的结构图像。此项技术在临床诊断、科学研究的应用成为现实,MRI的技术应用在医学、神经学、生理学的诊断和治疗方面起到至关重要的作用。MRI具有高分辨率、无创以及可重复检查等优点,能够非常好的区分动脉粥样硬化斑块的组成成分和形态学特征。而现如今,应用MRI技术临床的研究热门话题是对易损斑块进行筛查和性质评估。文章对MRI检测易损斑块的优势与不足进行综述。
基金Supported by the grants from the Talented Scholar Foundation of Jiangsu Province (No. RC2003094)the Sci-Tech research Foundation of Jiangsu Province (No. H200517)"The Six Talent Peak" Project Foundation of Jiangsu Province (06-B-021)
文摘Objective: To establish an orthotopic bladder cancer model bearing human bladder cancer for experimental research, and monitor tumor progression by magnetic resonance imaging (MRI). Methods: The mucosa was mechanically damaged transurethrally under direct vision, and then human bladder cancer cell line T24 was inoculated into the bladders of BALB/c nude mice to establish orthotopic bladder cancer model. To find a suitable concentration of Gd-DTPA for this re- search. MRI was performed weekly to assess tumor growth, using Gd-DTPA as contrast agent. The pathologic morphology of the bladders and other specimens were observed with HE stain. Results: All the 25 mice developed bladder cancer after inoculation. The best concentration of Gd-DTPA was 1.408 mg/mL. On MRI, no change in the bladders was observed on day 7 after inoculation, filling defect in the bladders, accordant to actual tumor size, was detected on days 14, 21 and 28. Pathologic examination showed that tumor grew in the mucosa or superficial muscle of bladder on day 7, confined in muscle layer on days 14–28, and invaded serosa on day 35. Conclusion: Transurethrally damaged bladder mucosa under direct vision and instilled bladder cancer cell T24, we successfully established an orthotopic bladder cancer model. Tumor growth simulated the progression of human bladder cancer approximately. MRI was a reliable way for dynamic detection of murine orthotopic bladder tumor.
