High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; Christian Doppler Laboratory for Clinical Molecular MRI, Vienna, Austria.
High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria.
Neuroimage. 2018 Mar;168:477-489. doi: 10.1016/j.neuroimage.2016.11.031. Epub 2016 Nov 13.
The growing interest in ultra-high field MRI, with more than 35.000 MR examinations already performed at 7T, is related to improved clinical results with regard to morphological as well as functional and metabolic capabilities. Since the signal-to-noise ratio increases with the field strength of the MR scanner, the most evident application at 7T is to gain higher spatial resolution in the brain compared to 3T. Of specific clinical interest for neuro applications is the cerebral cortex at 7T, for the detection of changes in cortical structure, like the visualization of cortical microinfarcts and cortical plaques in Multiple Sclerosis. In imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology may be visualized with excellent spatial resolution. Using Susceptibility Weighted Imaging, the plaque-vessel relationship and iron accumulations in Multiple Sclerosis can be visualized, which may provide a prognostic factor of disease. Vascular imaging is a highly promising field for 7T which is dealt with in a separate dedicated article in this special issue. The static and dynamic blood oxygenation level-dependent contrast also increases with the field strength, which significantly improves the accuracy of pre-surgical evaluation of vital brain areas before tumor removal. Improvement in acquisition and hardware technology have also resulted in an increasing number of MR spectroscopic imaging studies in patients at 7T. More recent parallel imaging and short-TR acquisition approaches have overcome the limitations of scan time and spatial resolution, thereby allowing imaging matrix sizes of up to 128×128. The benefits of these acquisition approaches for investigation of brain tumors and Multiple Sclerosis have been shown recently. Together, these possibilities demonstrate the feasibility and advantages of conducting routine diagnostic imaging and clinical research at 7T.
超高场 MRI 的日益普及，已经有超过 35000 次的 7T 磁共振检查，这与形态学以及功能和代谢能力的临床改善结果有关。由于信号与噪声比随磁共振扫描仪的场强而增加，因此在 7T 下最明显的应用是与 3T 相比，在大脑中获得更高的空间分辨率。神经应用的具体临床关注是 7T 下的大脑皮层，用于检测皮质结构的变化，例如多发性硬化症中皮质微梗死和皮质斑块的可视化。在海马成像中，甚至可以用出色的空间分辨率可视化内部海马解剖结构和病理学的亚区。使用磁化率加权成像，可以可视化多发性硬化症中的斑块-血管关系和铁堆积，这可能提供疾病的预后因素。血管成像在 7T 下是一个非常有前途的领域，在本特刊的一篇单独的专题文章中进行了讨论。静态和动态血氧水平依赖性对比也随场强而增加，这显著提高了在肿瘤切除前对重要脑区进行术前评估的准确性。采集和硬件技术的改进也导致在 7T 下进行越来越多的磁共振波谱成像研究。最近的并行成像和短 TR 采集方法克服了扫描时间和空间分辨率的限制，从而允许使用高达 128×128 的成像矩阵大小。最近已经证明了这些采集方法对脑肿瘤和多发性硬化症的研究的益处。总之，这些可能性证明了在 7T 下进行常规诊断成像和临床研究的可行性和优势。
