Matsusue Eiji, Ogawa Toshihide
Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36 1 Nishi cho, Yonago shi, Tottori 683 8504, Japan.
Brain Nerve. 2007 May;59(5):479-85.
Recently, the introduction of 3 tesla (3T) magnetic resonance (MR) system for more sophisticated clinical applications has yielded in important benefits, especially in neuroradiology. The aim of this article is to illustrate the practical scientific applications of the 3T system in the neuroradiological filed. From the clinical point of view, we focused on the usefulness of 3T system for the diagnosis of several neurological disorders, such as brain tumors, vascular lesions, hemorrhagic lesions, acute cerebral infarcts and degenerative diseases. The greatest advantage of high-field MR system is a higher signal to noise ratio. This higher spatial resolution can provide precise anatomical information for brain tumor itself and its surrounding structures. Diffusion weighted imaging (DWI) also benefits from the higher signal to noise ratio and offers useful information for tumor characteristics. Navigation system with diffusion tensor tractgraphy is also available for surgical operation of brain tumors. Parallel imaging enables to improve the quality of tractgraphy by reducing susceptibility artifacts. 3T TOF (time-of-flight) MR angiography (MRA) demonstrates superior depiction of intracranial aneurysms compared with that of 1.5T TOF MRA. 3T TOF MRA is also useful for the evaluation and follow-up of stenoocclusive diseases including moyamoya disease. Susceptibility weighted imaging (SWI) is a BOLD (blood oxygenation level dependent)-sensitive method for visualizing anatomical features such as small cerebral veins in high detail. Therefore, 3T system has advantages for obtaining detailed, high spatial resolution images of the venous network. SWI is useful for detection of hemorrhagic lesions and early diagnosis of acute hemorrhagic infarcts. SWI also can detect embolus and evaluate functional changes showing dilatation of medullary veins in the area of acute cerebral infarcts. Neuromelanin imaging using 3T system can directly demonstrate the locus ceruleus and substantia nigra by the neuromelanin content and have the potential to become a powerful tool in Parkinson's disease and other neurodegenerative disorders with Parkinsonism. Hyperintense putaminal rim can be often observed in clinically normal subjects on fast spin echo T2-weighted images at 3T system. This finding should not be mistaken for multiple system atrophy. 3T MR system indeed offers new potential because of a substantial increase in signal intensity provided by the higher magnetic field. Routine neuroradiologic imaging would benefit from higher magnetic field. However, It is required that extended knowledge of clinical data in comparison with 1.5T system to elucidate the efficacy of 3T system in the neuroradiology.
最近,3特斯拉(3T)磁共振(MR)系统被引入用于更复杂的临床应用,已带来了重要益处,尤其是在神经放射学领域。本文的目的是阐述3T系统在神经放射学领域的实际科学应用。从临床角度来看,我们重点关注3T系统在诊断多种神经系统疾病方面的实用性,如脑肿瘤、血管病变、出血性病变、急性脑梗死和退行性疾病。高场MR系统的最大优势是具有更高的信噪比。这种更高的空间分辨率能够为脑肿瘤本身及其周围结构提供精确的解剖信息。扩散加权成像(DWI)也受益于更高的信噪比,并能为肿瘤特征提供有用信息。带有扩散张量纤维束成像的导航系统也可用于脑肿瘤的手术操作。并行成像通过减少磁敏感伪影能够提高纤维束成像的质量。与1.5T时间飞跃(TOF)磁共振血管造影(MRA)相比,3T TOF MRA对颅内动脉瘤的显示更优。3T TOF MRA也可用于包括烟雾病在内的狭窄闭塞性疾病的评估和随访。磁敏感加权成像(SWI)是一种对血氧水平依赖(BOLD)敏感的方法,能够非常详细地显示诸如脑内小静脉等解剖特征。因此,3T系统在获取静脉网络详细的、高空间分辨率图像方面具有优势。SWI有助于检测出血性病变和急性出血性梗死的早期诊断。SWI还能检测栓子,并评估急性脑梗死区域显示髓静脉扩张的功能变化。使用3T系统的神经黑色素成像能够通过神经黑色素含量直接显示蓝斑和黑质,并且有可能成为帕金森病和其他具有帕金森综合征表现的神经退行性疾病的有力诊断工具。在3T系统的快速自旋回波T2加权图像上,临床上正常的受试者经常可以观察到壳核边缘高信号。这一发现不应被误诊为多系统萎缩。由于更高磁场提供的信号强度大幅增加,3T MR系统确实提供了新的潜力。常规神经放射学成像将受益于更高的磁场。然而,与1.5T系统相比,需要扩展临床数据知识以阐明3T系统在神经放射学中的效能。