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超高场磁共振成像(ultra-high field magnetic resonance imaging, UHF-MRI)是主磁场强度为7 T及以上磁共振成像的统称. 与传统磁共振成像相比, UHF-MRI具有更高的信噪比和对比度. 因此, 在临床医学及神经科学等领域, 该技术的运用能够显著提高信号的探测灵敏度和图像的空间分辨率, 从而提供更丰富的生理病理信息. 目前, UHF-MRI在大脑功能和代谢成像两个方面发挥了重要的作用. 在脑功能研究方面, 高分辨率的皮层功能柱和分层成像有助于揭示神经信息流的方向; 在脑代谢研究中, 氢核与多核的波谱及成像技术提供了更精确的代谢信息, 有望在功能性和代谢性疾病的病理研究中取得重要突破. 本文介绍了UHF-MRI的发展历史和理论基础, 梳理了其关键优势及在脑功能和代谢成像应用研究中的现状, 总结了当前面临的挑战, 并提出了未来重点研究方向.
Magnetic resonance imaging (MRI) is one of the most important imaging modalities used in contemporary clinical radiology research and diagnostic practice due to its non-invasive nature, absence of ionizing radiation, high soft tissue contrast, and diverse imaging capabilities. Nevertheless, traditional MRI systems are limited by a relatively low signal-to-noise ratio (SNR), which can be enhanced by increasing the strength of the main magnetic field. Ultra-high field MRI (UHF-MRI) typically refers to MRI systems with a main magnetic field strength of 7 T or higher. The UHF-MRI improves image SNR and extends the boundaries of spatial resolution and detection sensitivity. These advancements not only provide clinicians with richer and more accurate physiological and pathological information but also open new avenues for research on life sciences and cognitive neuroscience. Currently, the UHF-MRI plays a pivotal role in brain functional and metabolic imaging. In the brain function research, the implementation of high-resolution mesoscale functional imaging techniques has enabled the investigation of laminar-specific neuronal activity within cortical layers, including feedforward and feedback neural information processing pathways. In metabolic studies, the application of hydrogen and multi-nuclear spectroscopy and imaging has yielded more accurate metabolic data, thereby holding substantial promise for advancing our understanding of the pathophysiology underlying functional and metabolic diseases. However, the UHF-MRI is also subject to certain limitations, including issues related to radio-frequency (RF) field in homogeneity, elevated specific absorption ratio (SAR), and susceptibility artifacts. In this paper, the historical evolution and theoretical underpinnings of UHF-MRI are reviewed, its principal advantages over low-field MRI is elucidated, and the contemporary research on UHF-MRI applications in human brain function and metabolic imaging research are integrated together. Furthermore, the technical limitations associated with UHF-MRI implementation are critically examined and the potential avenues are proposed for the future research direction. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] [80] [81] [82] [83] [84] [85] [86] [87] [88] [89] [90] [91] [92] [93] [94] [95] [96] [97] [98] [99] [100] [101] [102] [103] [104] [105] [106] [107] [108] [109] [110] [111] [112] [113] [114] [115] [116] [117] [118] [119] [120] [121] [122] [123] [124] [125] [126] [127] [128] [129] [130] [131] [132] [133] [134] [135] [136] [137] [138] [139] [140] [141] [142] [143] [144] [145] [146] [147] [148] [149] [150] [151] [152] [153] [154] [155] [156] [157] [158] [159] [160] [161] [162] [163] [164] [165] [166] [167] [168] [169] [170] [171] [172] [173] [174] [175] [176] [177] [178] [179] [180] [181] [182] [183] [184] [185] [186] [187] [188] [189] [190] [191] [192] [193] [194] [195] [196] [197] [198] [199] [200] -
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