Balchandani P, Naidich T P
From the Translational and Molecular Imaging Institute (P.B.) Department of Radiology (P.B., T.P.N.), Icahn School of Medicine at Mount Sinai, New York, New York.
Department of Radiology (P.B., T.P.N.), Icahn School of Medicine at Mount Sinai, New York, New York.
AJNR Am J Neuroradiol. 2015 Jul;36(7):1204-15. doi: 10.3174/ajnr.A4180. Epub 2014 Dec 18.
At ultra-high magnetic fields, such as 7T, MR imaging can noninvasively visualize the brain in unprecedented detail and through enhanced contrast mechanisms. The increased SNR and enhanced contrast available at 7T enable higher resolution anatomic and vascular imaging. Greater spectral separation improves detection and characterization of metabolites in spectroscopic imaging. Enhanced blood oxygen level-dependent contrast affords higher resolution functional MR imaging. Ultra-high-field MR imaging also facilitates imaging of nonproton nuclei such as sodium and phosphorus. These improved imaging methods may be applied to detect subtle anatomic, functional, and metabolic abnormalities associated with a wide range of neurologic disorders, including epilepsy, brain tumors, multiple sclerosis, Alzheimer disease, and psychiatric conditions. At 7T, however, physical and hardware limitations cause conventional MR imaging pulse sequences to generate artifacts, requiring specialized pulse sequences and new hardware solutions to maximize the high-field gain in signal and contrast. Practical considerations for ultra-high-field MR imaging include cost, siting, and patient experience.
在超高磁场（如7T）下，磁共振成像（MR成像）能够以前所未有的细节并通过增强的对比机制对大脑进行无创可视化。7T时信噪比的提高和对比度的增强使得能够进行更高分辨率的解剖和血管成像。更大的光谱分离度改善了磁共振波谱成像中代谢物的检测和特征描述。增强的血氧水平依赖对比度实现了更高分辨率的功能磁共振成像。超高场MR成像还便于对钠和磷等非质子核进行成像。这些改进的成像方法可用于检测与多种神经系统疾病（包括癫痫、脑肿瘤、多发性硬化症、阿尔茨海默病和精神疾病）相关的细微解剖、功能和代谢异常。然而，在7T时，物理和硬件限制会导致传统MR成像脉冲序列产生伪影，这就需要专门的脉冲序列和新的硬件解决方案，以最大限度地提高高场下信号和对比度的增益。超高场MR成像的实际考虑因素包括成本、场地选址和患者体验。
