Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94158-2330, USA.
Curr Opin Neurol. 2011 Dec;24(6):605-15. doi: 10.1097/WCO.0b013e32834cd495.
The last 5 years have seen the number of ultra-high field (UHF; 7 T and beyond) MRI scanners nearly double. Benefits include improved specificity, better sensitivity for signal-starved compounds, and the ability to detect, quantify, and monitor tumor activity and treatment effects. This is especially important in the current climate in which new treatments alter established markers of tumor and the surrounding environment, confounding traditional response criteria.
Intra-tumoral heterogeneity and dramatic improvement in spatial localization have been observed with 7 and 8 T high-resolution T2-weighted and T2*-weighted imaging. This depiction of lesions that were not readily detected at lower field improved the classification of glioma. Sub-millimeter visualization of microvasculature has facilitated the detection of microbleeds associated with long-term effects of radiation. New metabolic markers seen at UHF may also assist in distinguishing tumor progression from treatment effect.
Although progress has been limited by technical challenges, initial experience has demonstrated the promise of 7-T MRI in advancing existing paradigms for diagnosing, monitoring, and managing patients with brain tumors. The success of these systems will depend upon what new information can be gained by UHF, rather than simply improving the quality of the current lower field standard.
在过去的 5 年中，超高场（UHF；7T 及以上）MRI 扫描仪的数量几乎翻了一番。其带来的益处包括提高特异性、改善对信号匮乏化合物的敏感性，以及检测、量化和监测肿瘤活性和治疗效果的能力。这在当前新治疗方法改变肿瘤和周围环境的既定标志物、混淆传统反应标准的情况下尤为重要。
在 7T 和 8T 高分辨率 T2 加权和 T2*-加权成像中观察到了肿瘤内异质性和空间定位的显著改善。这种对在较低场不易检测到的病变的描绘改善了对胶质瘤的分类。亚毫米级的微血管可视化促进了与辐射长期效应相关的微出血的检测。在 UHF 下观察到的新代谢标志物也可能有助于区分肿瘤进展与治疗效果。
尽管技术挑战限制了进展，但初步经验表明，7T MRI 在推进现有诊断、监测和管理脑肿瘤患者的范式方面具有广阔的前景。这些系统的成功将取决于 UHF 能获得哪些新信息，而不仅仅是提高当前较低场标准的质量。
