Ultrahigh field MR Neuroimaging.
Ultrahigh field MR Neuroimaging.
复制标题
超高场磁共振神经成像。
DOI：
10.1097/rmr.0000000000000210
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Balchandani,Priti
中科院分区：
文献类型：
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作者：
Verma,Gaurav;Balchandani,Priti
在最早采集磁共振（MR）衍生的大脑图像四十年后，MR技术已发展成为各种临床应用中必不可少的诊断工具。这一发展的核心是人类磁共振扫描仪的发展，其磁场越来越大，最近的磁场强度为7特斯拉（T）或更高（高达11.7 T）。1这些双磁场磁共振扫描仪有潜力实现前所未有的神经成像细节，从而更好地表征正常组织和病理病变，并改善治疗计划和反应监测。截至2019年初，根据层fMRI博客的Renzo Huber开发的数据库，全球至少安装了76个7T或更高场强的全身MRI系统。7T Terra（Siemens Healthineers，埃尔兰根，德国）系统已成为首个获得临床成像510（k）许可的医疗器械领域系统。信噪比（SNR）和组织对比度是MRI实用性的两个核心考虑因素，两者均与场强成比例（见表1）。2-12之前对高场（3 T）和超高场MRI（7 T及以上）的比较研究已经经验性地证明了场强和SNR之间可能存在超线性关系。13，14这种比传统扫描仪更高的SNR的结果是，通常可以以更高的分辨率和更好的精细解剖结构区分来采集双视场图像。[15]这种更高的灵敏度可能有助于建立诸如脑肿瘤、阿尔茨海默病、神经精神疾病（如抑郁症、创伤后应激障碍和精神分裂症）以及神经系统疾病（如癫痫和多发性硬化症）等疾病的生物标志物的成像。作为一项前沿技术，超视场成像并非没有其技术挑战。实现超高场神经成像的临床潜力需要解决诸如更大的B0和B1不均匀性和比吸收率（SAR）等问题。
Four decades following the earliest acquisition of magnetic resonance (MR) derived images of the brain, MR technology has developed into an essential diagnostic tool across a diverse range of clinical applications. Central to this evolution has been the development of human MR scanners with increasingly greater magnetic fields, most recently those operating at field strengths of 7 tesla (T) or more (up to 11.7 T). 1 These ultrahigh field MR scanners have the potential to permit neuroimaging with unprecedented detail, leading to better characterization of normal tissue and pathologic lesions and improved planning of treatment and monitoring of response. As of early 2019, at least 76 whole-body MRI systems of 7T or greater field strength have been installed around the world according to a database developed by Renzo Huber of the layer fMRI blog. The 7T Terra (Siemens Healthineers, Erlangen, Germany) system has become the first ultrahigh field system to receive 510 (k) clearance for clinical imaging. Signal-to-noise (SNR) and tissue contrast, 2 considerations central to the utility of MRI, both scale proportionally with field strength (see Table 1). 2–12 Previous comparative studies across high (3T) and ultrahigh field MRI (7T and above) have empirically demonstrated a potentially supralinear relationship between field strength and SNR. 13, 14 A consequence of this greater SNR than conventional scanners is that images at ultrahigh field can typically be acquired with greater resolution and better differentiation of fine anatomical structures. 15 This greater sensitivity of ultrahigh field imaging may help to establish imaging of biomarkers for diseases such as brain tumors, Alzheimer disease, 16 neuropsychiatric disorders such as depression, post-traumatic stress, and schizophrenia, and neurological disorders such as epilepsy and multiple sclerosis. As a leading-edge technology, ultrahigh field imaging is not without its technical challenges. Realizing the clinical potential of ultrahighfield neuroimaging requires addressing issues such as greater B0 and B1 inhomogeneity and specific absorption rates (SARs).