Methionine positron emission tomography of recurrent metastatic brain tumor and radiation necrosis after stereotactic radiosurgery: is a differential diagnosis possible?

• DOI: 10.3171/jns.2003.98.5.1056
• Publication Date: 2009-05-13T17:57:34Z
• Authors: Naohiro Tsuyuguchi; Ichiro Sunada; Yoshiyasu Iwai; Kazuhiro Yamanaka; Kiyoaki Tanaka; Toshihiro Takami; Yumiko Otsuka; Shinichi Sakamoto; Kenji Ohata; Takeo Goto; Mitsuhiro Hara
• Keywords: Stereotactic biopsy; Brain tumor; Standardized uptake value

Object. In this study the authors examined how to differentiate radiation necrosis from recurrent metastatic brain tumor following stereotactic radiosurgery by using positron emission tomography (PET) with l -[methyl- 11 C]methionine (MET). Methods. 21 adult patients suspected or injury, MET-PET scans were obtained. These had previously undergone and subsequent contrast-enhanced magnetic resonance (MR) examinations before nuclear medicine imaging. Positron images obtained as a static scan of 10 minutes performed 20 after injection 370 MBq MET. On scans, portion highest accumulation MET was selected region interest (ROI), ratio tissue normal (T/N) defined mean counts radioisotope per pixel in divided gray matter. The standardized uptake value (SUV) calculated same ROI tumor. accuracy evaluated correlating findings results histological analysis (11 cases) or, cases which surgery biopsy not performed, clinical course MR imaging (10 cases). Histological showed viable cells nine no two. Another characterized because exhibited stable neurological symptoms sign massive enlargement lesion on follow-up 5 months. T/N 1.15 group (12 1.62 recurrence (nine SUV 1.78 2.5 group. There statistically significant differences between groups SUV. Furthermore, borderline 1.42 according 2 × factorial table (high low T/N, necrosis). From result, sensitivity specificity scanning detecting determined be 77.8 100%, respectively. Conclusions. use is sensitive accurate technique for differentiating radiosurgery. This reveals important information creating strategies treat postradiation reactions.