Neuroradiology Research Unit, Neuroscience Department, A Meyer Children's Hospital, University of Florence, Florence, Italy.
Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, Florence, Italy.
Essays Biochem. 2018 Jul 20;62(3):409-421. doi: 10.1042/EBC20170109.
MRI and H magnetic resonance spectroscopy (HMRS) are the main neuroimaging methods to study mitochondrial diseases. MRI can demonstrate seven 'elementary' central nervous system (CNS) abnormalities in these disorders, including diffuse cerebellar atrophy, cerebral atrophy, symmetric signal changes in subcortical structures (basal ganglia, brainstem, cerebellum), asymmetric signal changes in the cerebral cortex and subcortical white matter, leukoencephalopathy, and symmetric signal changes in the optic nerve and the spinal cord. These elementary MRI abnormalities can be variably combined in the single patient, often beyond what can be expected based on the classically known clinical-pathological patterns. However, a normal brain MRI is also possible. HMRS has a diagnostic role in patients with suspected mitochondrial encephalopathy, especially in the acute phase, as it can detect within the lesions, but also in normal appearing nervous tissue or in the ventricular cerebrospinal fluid (CSF), an abnormally prominent lactate peak, reflecting failure of the respiratory chain with a shift from the Krebs cycle to anaerobic glycolysis. So far, studies correlating MRI findings with genotype in mitochondrial disease have been possible only in small samples and would greatly benefit from data pooling. MRI and HMRS have provided important information on the pathophysiology of CNS damage in mitochondrial diseases by enabling non-invasive assessment of tissue abnormalities, the associated changes of blood perfusion and cellular metabolic derangement. MRI and HMRS are expected to serve as surrogate biomarkers in trials investigating therapeutic options in mitochondrial disease.
MRI 和 H 磁共振波谱（HMRS）是研究线粒体疾病的主要神经影像学方法。MRI 可以显示这些疾病中七个“基本”的中枢神经系统（CNS）异常，包括弥漫性小脑萎缩、大脑萎缩、皮质下结构（基底节、脑干、小脑）的对称性信号改变、大脑皮层和皮质下白质的不对称性信号改变、白质脑病和视神经和脊髓的对称性信号改变。这些基本的 MRI 异常在单个患者中可以不同程度地组合，通常超出基于经典已知临床病理模式的预期。然而，也可能出现正常的脑部 MRI。HMRS 在疑似线粒体脑病的患者中具有诊断作用，特别是在急性期，因为它可以在病变内检测到，也可以在正常表现的神经组织或脑室脑脊液（CSF）中检测到异常突出的乳酸峰，反映呼吸链衰竭，克雷布斯循环向无氧糖酵解转移。到目前为止，只有在小样本中才有可能将 MRI 发现与线粒体疾病的基因型相关联，并且数据汇集将大大受益。MRI 和 HMRS 通过非侵入性评估组织异常、相关的血液灌注变化和细胞代谢紊乱，为线粒体疾病中 CNS 损伤的病理生理学提供了重要信息。MRI 和 HMRS 有望成为线粒体疾病治疗选择研究中的替代生物标志物。
