Chen Wei
Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California-Los Angeles, CA, USA.
J Nucl Med. 2007 Sep;48(9):1468-81. doi: 10.2967/jnumed.106.037689. Epub 2007 Aug 17.
Malignant gliomas and metastatic tumors are the most common brain tumors. Neuroimaging plays a significant role clinically. In low-grade tumors, neuroimaging is needed to evaluate recurrent disease and to monitor anaplastic transformation into high-grade tumors. In high-grade and metastatic tumors, the imaging challenge is to distinguish between recurrent tumor and treatment-induced changes such as radiation necrosis. The current clinical gold standard, MRI, provides superior structural detail but poor specificity in identifying viable tumors in brain treated with surgery, radiation, or chemotherapy. (18)F-FDG PET identifies anaplastic transformation and has prognostic value. The sensitivity and specificity of (18)F-FDG in evaluating recurrent tumor and treatment-induced changes can be improved significantly by co-registration with MRI and potentially by delayed imaging 3-8 h after injection. Amino acid PET tracers are more sensitive than (18)F-FDG in imaging recurrent tumors and in particular recurrent low-grade tumors. They are also promising in differentiating between recurrent tumors and treatment-induced changes.
恶性胶质瘤和转移性肿瘤是最常见的脑肿瘤。神经影像学在临床上发挥着重要作用。在低级别肿瘤中，需要神经影像学来评估复发性疾病并监测向高级别肿瘤的间变转化。在高级别和转移性肿瘤中，影像学面临的挑战是区分复发性肿瘤和治疗引起的变化，如放射性坏死。当前的临床金标准MRI在识别接受手术、放疗或化疗的脑部存活肿瘤方面提供了出色的结构细节，但特异性较差。（18）F-FDG PET可识别间变转化并具有预后价值。通过与MRI共同配准，以及可能在注射后3至8小时进行延迟成像，（18）F-FDG在评估复发性肿瘤和治疗引起的变化方面的敏感性和特异性可得到显著提高。氨基酸PET示踪剂在成像复发性肿瘤，尤其是复发性低级别肿瘤方面比（18）F-FDG更敏感。它们在区分复发性肿瘤和治疗引起的变化方面也很有前景。
