Department of Neurosurgery, Osaka University Gradate School of Medicine, 2-2 Yamadoka, Suita, Osaka 565-0871, Japan.
J Neurooncol. 2012 Jan;106(2):417-25. doi: 10.1007/s11060-011-0688-0. Epub 2011 Aug 17.
Discriminating tumor infiltrative and vasogenic brain edema in malignant gliomas is important although challenging in clinical settings. This study challenged this issue by performing voxel-wise analysis of (18)F-fluorodeoxy glucose (FDG) and (11)C-methionine positron emission tomography (PET) in peritumoral brain edemas. The authors studied ten malignant glioma and nine meningioma patients with peritumoral brain edema. A voxel-wise analysis of FDG and (11)C-methionine PET was performed in order to quantify the correlation between uptake of these tracers in normal brain tissue and peritumoral brain edema. Decoupling score of the uptake of two tracers was calculated as the z-score from the estimated correlation between uptake of the two tracers in normal brain tissue. The decoupling score was also converted into images for visual inspection. Average decoupling score in the peritumoral brain edema was calculated and compared between those obtained from malignant gliomas and meningiomas. FDG and (11)C-methionine uptake showed a reproducible linear correlation in normal brain tissue. This correlation was preserved in peritumoral edema of meningioma, but not in that of malignant gliomas. In malignant gliomas, higher (11)C-methionine uptake compared to that estimated by the FDG uptake in normal brain tissue was observed, thus suggesting that decoupling was caused by tumor infiltration. Visual inspection of the decoupling score enabled discrimination of tumor infiltrative and vasogenic edema. The average decoupling scores of the peritumoral brain edema in malignant gliomas were significantly higher than those in meningiomas (2.9 vs. 0.7, P = 0.0003). As a conclusion, FDG/(11)C-methionine uptake decoupling score can be used for the discrimination of tumor infiltrative and vasogenic brain edema. The proposed method also suggests the possibility of accurately detecting tumor infiltration into brain tissues in gliomas, providing significant information for treatment planning and follow-up.
鉴别恶性胶质瘤中的肿瘤浸润性和血管源性脑水肿是非常重要的，尽管在临床环境中具有挑战性。本研究通过对瘤周脑水肿进行（18）F-氟脱氧葡萄糖（FDG）和（11）C-蛋氨酸正电子发射断层扫描（PET）的体素分析来解决这个问题。作者研究了 10 例恶性胶质瘤和 9 例脑膜瘤患者的瘤周脑水肿。进行了 FDG 和（11）C-蛋氨酸 PET 的体素分析，以定量测量这些示踪剂在正常脑组织和瘤周脑水肿中的摄取之间的相关性。计算了两种示踪剂摄取的去耦分数，方法是将两种示踪剂在正常脑组织中的摄取相关性的估计值转换为 z 分数。还将去耦分数转换为图像进行目视检查。计算了瘤周脑水肿中的平均去耦分数，并将其与从恶性胶质瘤和脑膜瘤获得的分数进行比较。FDG 和（11）C-蛋氨酸摄取在正常脑组织中显示出可重复的线性相关性。这种相关性在脑膜瘤的瘤周水肿中得以保留，但在恶性胶质瘤中则没有。在恶性胶质瘤中，与正常脑组织中 FDG 摄取相比，观察到（11）C-蛋氨酸摄取更高，因此表明去耦是由肿瘤浸润引起的。对去耦分数的目视检查能够区分肿瘤浸润性和血管源性水肿。恶性胶质瘤瘤周脑水肿的平均去耦分数明显高于脑膜瘤（2.9 对 0.7，P = 0.0003）。总之，FDG/（11）C-蛋氨酸摄取去耦分数可用于鉴别肿瘤浸润性和血管源性脑水肿。该方法还表明，有可能准确检测胶质瘤对脑组织的浸润，为治疗计划和随访提供重要信息。
