Patsouris A, Augereau P, Tanguy J-Y, Morel O, Menei P, Rousseau A, Paumier A
Service d'oncologie médicale, institut de cancérologie de l'Ouest Paul-Papin, 2, rue Moll, 49000 Angers, France.
Service de radiologie, centre hospitalier universitaire, université d'Angers, 4, rue Larrey, 49933 Angers cedex 9, France; Université Nantes Angers Le Mans (Unam), 4, rue Larrey, 49933 Angers cedex 9, France.
Cancer Radiother. 2014 Mar;18(2):142-6. doi: 10.1016/j.canrad.2013.10.013. Epub 2014 Jan 13.
Magnetic resonance imaging (MRI) is a method of choice for follow-up of irradiated brain metastasis. It is difficult to differentiate local tumour recurrences from radiation induced-changes in case of suspicious contrast enhancement. New advanced MRI techniques (perfusion and spectrometry) and amino acid positron-emission tomography (PET) allow to be more accurate and could avoid a stereotactic biopsy for histological assessment, the only reliable but invasive method. We report the case of a patient who underwent surgery for a single, left frontal brain metastasis of a breast carcinoma, followed by adjuvant stereotactic radiotherapy in the operative bed. Seven months after, she presented a local change in the irradiated area on the perfusion-weighted MRI, for which the differentiation between a local tumour recurrence and radionecrosis was not possible. PET with 2-deoxy-((18)F)-fluoro-D-glucose (FDG) revealed a hypermetabolic lesion. After surgical resection, the histological assessment has mainly recovered radionecrosis with few carcinoma cells. The multimodal MRI has greatly contributed to refine the differential diagnosis between tumour recurrence and radionecrosis, which remains difficult. The FDG PET is helpful, in favour of the diagnosis of local tumour recurrence when a hypermetabolic lesion is found. Others tracers (such as carbon 11 or a fluoride isotope) deserve interest but are not available in all centres. Stereotactic biopsy should be discussed if any doubt remains.
磁共振成像（MRI）是随访经放疗的脑转移瘤的首选方法。在出现可疑的对比增强时，很难区分局部肿瘤复发与放疗引起的改变。新的先进MRI技术（灌注和波谱分析）以及氨基酸正电子发射断层扫描（PET）能提高诊断准确性，避免采用立体定向活检进行组织学评估，立体定向活检是唯一可靠但具有侵入性的方法。我们报告了一例患者，该患者因单一左额叶乳腺癌脑转移接受手术治疗，术后在手术床部位接受辅助立体定向放疗。七个月后，她在灌注加权MRI上显示放疗区域出现局部改变，无法区分是局部肿瘤复发还是放射性坏死。用2-脱氧-（（18）F）-氟-D-葡萄糖（FDG）进行PET检查显示有一个高代谢病灶。手术切除后，组织学评估主要显示为放射性坏死，仅有少量癌细胞。多模态MRI对细化肿瘤复发和放射性坏死之间的鉴别诊断有很大帮助，而这一鉴别诊断仍然困难。当发现高代谢病灶时，FDG PET有助于诊断局部肿瘤复发。其他示踪剂（如碳11或氟同位素）值得关注，但并非所有中心都能使用。如果仍有疑问，应考虑进行立体定向活检。
