多系统萎缩(multiple system atrophy,MSA)是一种罕见的、成年起病的神经退行性疾病,其临床表现多样,发病机制尚不明确,疾病诊断十分困难。形态学变化的脑干亚结构与MSA的出现和发展有关。基于体素的形态学分析技术(voxel-based morphom...多系统萎缩(multiple system atrophy,MSA)是一种罕见的、成年起病的神经退行性疾病,其临床表现多样,发病机制尚不明确,疾病诊断十分困难。形态学变化的脑干亚结构与MSA的出现和发展有关。基于体素的形态学分析技术(voxel-based morphometry,VBM)可以实现对脑干亚结构的灰质和白质的密度及体积的量化分析,进而发现MSA患者的脑桥和中脑等区域的脑干结构异常。7T高场强磁共振(7-tesla high-field magnetic resonance imaging,7TMRI)不仅具有很高的空间分辨率及信噪比,还可以清晰地显示脑干的细微亚结构改变。VBM在较低分辨率的图像上对脑干亚结构的定位具有一定的精度,7TMRI可以展现细微的结构改变,但缺乏精准的定量分析,故将VBM与7TMRI深入融合可以利用7T的高分辨率特点对脑干亚结构的定位精度进行提升,并通过VBM的定量分析方法对7TMRI所示的细微的结构改变进行精准量化,力求做到尽可能全面及精准地揭示MSA患者的脑干亚结构形态变化,提供对MSA进行早期诊断、病情监测等有效证据。展开更多
缺血性脑卒中的病因分型对临床治疗决策和预后判断有重要价值。近年来,随着高分辨率磁共振血管壁成像(high-resolution vessel wall magnetic resonance imaging,HR-VW-MRI)在脑卒中临床研究和实践中的应用增加,7 T MRI以其更高信噪比...缺血性脑卒中的病因分型对临床治疗决策和预后判断有重要价值。近年来,随着高分辨率磁共振血管壁成像(high-resolution vessel wall magnetic resonance imaging,HR-VW-MRI)在脑卒中临床研究和实践中的应用增加,7 T MRI以其更高信噪比和更优图像质量,可发现脑血管早期、细微的病理变化,为深入了解各种脑血管疾病的病理机制提供了新思路。然而,超高场强也存在B1场不均、扫描时间长等技术挑战。本文就7 T HR-VW-MRI在缺血性卒中病因分型及临床应用中的进展进行综述,深入分析7 T HR-VW-MRI在提升临床诊断精确性与指导临床治疗中的潜在价值,为临床实践与科研探索提供参考。展开更多
The development of 7‐Tesla(7T)magnetic resonance imaging systems has opened new avenues for exploring the advantages of diffusion imaging at higher field strengths,especially in neuroscience research.This review inve...The development of 7‐Tesla(7T)magnetic resonance imaging systems has opened new avenues for exploring the advantages of diffusion imaging at higher field strengths,especially in neuroscience research.This review investigates whether 7T diffusion imaging offers significant benefits over lower field strengths by addressing the following:Technical challenges and corresponding strategies:Challenges include achieving shorter transverse relaxation/effective transverse relaxation times and greater B0 and B1 inhomogeneities.Advanced techniques including high‐performance gradient systems,parallel imaging,multi‐shot acquisition,and parallel transmission can mitigate these issues.Comparison of 3‐Tesla and 7T diffusion imaging:Technologies such as multiplexed sensitivity encoding and deep learning reconstruction(DLR)have been developed to mitigate artifacts and improve image quality.This comparative analysis demonstrates significant improvements in the signal‐to‐noise ratio and spatial resolution at 7T with a powerful gradient system,facilitating enhanced visualization of microstructural changes.Despite greater geometric distortions and signal inhomogeneity at 7T,the system shows clear advantages in high b‐value imaging and highresolution diffusion tensor imaging.Additionally,multiplexed sensitivity encoding significantly reduces image blurring and distortion,and DLR substantially improves the signal‐to‐noise ratio and image sharpness.7T diffusion applications in structural analysis and disease characterization:This review discusses the potential applications of 7T diffusion imaging in structural analysis and disease characterization.展开更多
AIM To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency microultrasound, 7T and 3T magnetic resonance imaging(MRI).METHODS Four subjects(ages 22-50 years) were scanned...AIM To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency microultrasound, 7T and 3T magnetic resonance imaging(MRI).METHODS Four subjects(ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer(Vevo 2100, Visual Sonics). Subjects' hands were then imaged on a 3T clinical MR scanner(Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects' hands were imaged on a 7T clinical MR scanner(Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall. RESULTS Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality(1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planarreformatting of images and allowed for less operator dependent results as compared to high frequency microultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall. CONCLUSION Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.展开更多
文摘多系统萎缩(multiple system atrophy,MSA)是一种罕见的、成年起病的神经退行性疾病,其临床表现多样,发病机制尚不明确,疾病诊断十分困难。形态学变化的脑干亚结构与MSA的出现和发展有关。基于体素的形态学分析技术(voxel-based morphometry,VBM)可以实现对脑干亚结构的灰质和白质的密度及体积的量化分析,进而发现MSA患者的脑桥和中脑等区域的脑干结构异常。7T高场强磁共振(7-tesla high-field magnetic resonance imaging,7TMRI)不仅具有很高的空间分辨率及信噪比,还可以清晰地显示脑干的细微亚结构改变。VBM在较低分辨率的图像上对脑干亚结构的定位具有一定的精度,7TMRI可以展现细微的结构改变,但缺乏精准的定量分析,故将VBM与7TMRI深入融合可以利用7T的高分辨率特点对脑干亚结构的定位精度进行提升,并通过VBM的定量分析方法对7TMRI所示的细微的结构改变进行精准量化,力求做到尽可能全面及精准地揭示MSA患者的脑干亚结构形态变化,提供对MSA进行早期诊断、病情监测等有效证据。
文摘缺血性脑卒中的病因分型对临床治疗决策和预后判断有重要价值。近年来,随着高分辨率磁共振血管壁成像(high-resolution vessel wall magnetic resonance imaging,HR-VW-MRI)在脑卒中临床研究和实践中的应用增加,7 T MRI以其更高信噪比和更优图像质量,可发现脑血管早期、细微的病理变化,为深入了解各种脑血管疾病的病理机制提供了新思路。然而,超高场强也存在B1场不均、扫描时间长等技术挑战。本文就7 T HR-VW-MRI在缺血性卒中病因分型及临床应用中的进展进行综述,深入分析7 T HR-VW-MRI在提升临床诊断精确性与指导临床治疗中的潜在价值,为临床实践与科研探索提供参考。
文摘The development of 7‐Tesla(7T)magnetic resonance imaging systems has opened new avenues for exploring the advantages of diffusion imaging at higher field strengths,especially in neuroscience research.This review investigates whether 7T diffusion imaging offers significant benefits over lower field strengths by addressing the following:Technical challenges and corresponding strategies:Challenges include achieving shorter transverse relaxation/effective transverse relaxation times and greater B0 and B1 inhomogeneities.Advanced techniques including high‐performance gradient systems,parallel imaging,multi‐shot acquisition,and parallel transmission can mitigate these issues.Comparison of 3‐Tesla and 7T diffusion imaging:Technologies such as multiplexed sensitivity encoding and deep learning reconstruction(DLR)have been developed to mitigate artifacts and improve image quality.This comparative analysis demonstrates significant improvements in the signal‐to‐noise ratio and spatial resolution at 7T with a powerful gradient system,facilitating enhanced visualization of microstructural changes.Despite greater geometric distortions and signal inhomogeneity at 7T,the system shows clear advantages in high b‐value imaging and highresolution diffusion tensor imaging.Additionally,multiplexed sensitivity encoding significantly reduces image blurring and distortion,and DLR substantially improves the signal‐to‐noise ratio and image sharpness.7T diffusion applications in structural analysis and disease characterization:This review discusses the potential applications of 7T diffusion imaging in structural analysis and disease characterization.
文摘AIM To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency microultrasound, 7T and 3T magnetic resonance imaging(MRI).METHODS Four subjects(ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer(Vevo 2100, Visual Sonics). Subjects' hands were then imaged on a 3T clinical MR scanner(Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects' hands were imaged on a 7T clinical MR scanner(Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall. RESULTS Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality(1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planarreformatting of images and allowed for less operator dependent results as compared to high frequency microultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall. CONCLUSION Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.
