Rodgers Zachary B, Detre John A, Wehrli Felix W
University of Pennsylvania Medical Center, Philadelphia, PA, USA Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Philadelphia, PA, USA.
University of Pennsylvania Medical Center, Philadelphia, PA, USA Center for Functional Neuroimaging, Department of Neurology, Philadelphia, PA, USA.
J Cereb Blood Flow Metab. 2016 Jul;36(7):1165-85. doi: 10.1177/0271678X16643090. Epub 2016 Apr 18.
The brain depends almost entirely on oxidative metabolism to meet its significant energy requirements. As such, the cerebral metabolic rate of oxygen (CMRO2) represents a key measure of brain function. Quantification of CMRO2 has helped elucidate brain functional physiology and holds potential as a clinical tool for evaluating neurological disorders including stroke, brain tumors, Alzheimer's disease, and obstructive sleep apnea. In recent years, a variety of magnetic resonance imaging (MRI)-based CMRO2 quantification methods have emerged. Unlike positron emission tomography - the current "gold standard" for measurement and mapping of CMRO2 - MRI is non-invasive, relatively inexpensive, and ubiquitously available in modern medical centers. All MRI-based CMRO2 methods are based on modeling the effect of paramagnetic deoxyhemoglobin on the magnetic resonance signal. The various methods can be classified in terms of the MRI contrast mechanism used to quantify CMRO2: T2*, T2', T2, or magnetic susceptibility. This review article provides an overview of MRI-based CMRO2 quantification techniques. After a brief historical discussion motivating the need for improved CMRO2 methodology, current state-of-the-art MRI-based methods are critically appraised in terms of their respective tradeoffs between spatial resolution, temporal resolution, and robustness, all of critical importance given the spatially heterogeneous and temporally dynamic nature of brain energy requirements.
大脑几乎完全依赖氧化代谢来满足其巨大的能量需求。因此，脑氧代谢率（CMRO2）是衡量脑功能的一项关键指标。CMRO2的量化有助于阐明脑功能生理学，并且作为评估包括中风、脑肿瘤、阿尔茨海默病和阻塞性睡眠呼吸暂停在内的神经系统疾病的临床工具具有潜力。近年来，出现了多种基于磁共振成像（MRI）的CMRO2量化方法。与正电子发射断层扫描（目前测量和绘制CMRO2的“金标准”）不同，MRI是非侵入性的，相对便宜，并且在现代医疗中心普遍可用。所有基于MRI的CMRO2方法都是基于对顺磁性脱氧血红蛋白对磁共振信号的影响进行建模。各种方法可以根据用于量化CMRO2的MRI对比机制进行分类：T2*、T2'、T2或磁化率。这篇综述文章概述了基于MRI的CMRO2量化技术。在简要回顾激发对改进CMRO2方法需求的历史讨论之后，基于MRI的当前最先进方法在空间分辨率、时间分辨率和稳健性之间各自的权衡方面受到了批判性评估，鉴于脑能量需求在空间上的异质性和时间上的动态性，所有这些都至关重要。
