Vella Alessandra, Mascalchi Mario
Nuclear Medicine, "Le Scotte" University Hospital, Siena, Italy.
Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy; Meyer Children's Hospital, Florence, Italy.
Handb Clin Neurol. 2018;154:251-266. doi: 10.1016/B978-0-444-63956-1.00015-1.
Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) with different radiotracers enable regional evaluation of blood flow and glucose metabolism, of receptors and transporters of several molecules, and of abnormal deposition of peptides and proteins in the brain. The cerebellum has been used as a reference region for different radiotracers in several disease conditions. Whole-brain voxel-wise analysis is not affected by a priori knowledge bias and should be preferred. SPECT and PET have contributed to establishing the cerebellum role in motion, cognition, and emotion control in physiologic and pathophysiologic conditions. The basic abnormal imaging findings include decreased or increased uptake of flow or metabolism tracers in the cerebellum alone or as part of a network. Decreased uptake is generally observed in primary structural damage of the cerebellum, but can also represent a distant effect of cerebral damage (crossed diaschisis). Increased uptake can be observed in Freidreich ataxia, inflammatory or immune-mediated diseases of the cerebellum, and in status epilepticus. The possibility is also recognized that primary structural damage of the cerebellum might determine distance effects on other brain structures (reversed diaschisis). So far, SPECT and PET have been predominantly used in clinical studies to investigate cerebellar changes in neurologic and psychiatric diseases and in connection with pharmacologic, transcranial magnetic stimulation, deep-brain stimulation, or surgical treatments.
单光子发射计算机断层扫描（SPECT）和正电子发射断层扫描（PET）结合不同的放射性示踪剂，能够对脑血流和葡萄糖代谢、多种分子的受体和转运体以及肽和蛋白质在脑内的异常沉积进行区域评估。在多种疾病状态下，小脑已被用作不同放射性示踪剂的参照区域。全脑体素分析不受先验知识偏差的影响，应优先选用。SPECT和PET有助于确立小脑在生理和病理生理状态下的运动、认知及情绪控制中的作用。基本的异常影像学表现包括小脑单独或作为网络的一部分，血流或代谢示踪剂摄取减少或增加。摄取减少通常见于小脑的原发性结构损伤，但也可能代表脑损伤的远隔效应（交叉性小脑失联络）。摄取增加可见于弗里德赖希共济失调、小脑的炎症或免疫介导性疾病以及癫痫持续状态。也认识到小脑的原发性结构损伤可能对其他脑结构产生远隔效应（反向性小脑失联络）的可能性。到目前为止，SPECT和PET主要用于临床研究，以调查神经和精神疾病中小脑的变化，以及与药物治疗、经颅磁刺激、深部脑刺激或手术治疗相关的情况。
