RT Journal Article
SR Electronic
T1 Methionine PET Findings in the Diagnosis of Brain Tumors and Non-Tumorous Mass Lesions: A Single-Center Report on 426 Cases
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP ajnr.A8871
DO 10.3174/ajnr.A8871
A1 Shiba, Yoshiki
A1 Aoki, Kosuke
A1 Ohka, Fumiharu
A1 Deguchi, Shoichi
A1 Yamaguchi, Junya
A1 Shimizu, Hiroki
A1 Maeda, Sachi
A1 Takido, Yuhei
A1 Yamamoto, Ryo
A1 Nakamura, Akihiro
A1 Saito, Ryuta
YR 2025
UL http://www.ajnr.org/content/early/2025/06/11/ajnr.A8871.abstract
AB BACKGROUND AND PURPOSE: Differentiating between a brain tumor and a non-tumorous lesion remains a significant diagnostic challenge, particularly when conventional imaging modalities such as CT and MRI provide inconclusive results. While MET–PET has shown potential in neuro-oncology, its diagnostic performance across a broad spectrum of brain pathologies has not been comprehensively evaluated. This study therefore assessed the sensitivity, specificity, and uptake patterns of MET–PET in a large cohort of brain lesions.MATERIALS AND METHODS: This single-center retrospective study analyzed 426 consecutive patients with undiagnosed brain lesions who underwent MET–PET imaging between January 2019 and May 2024. TNRs were calculated using a threshold of 1.5 for positive findings. Histological diagnoses were established based on the World Health Organization 2021 criteria, IDH mutation status and 1p/19q-codeletion.RESULTS: Among the cohort, 342 cases (67.8%) were confirmed as having tumorous lesions, 76 (17.8%) as having non-tumorous lesions, and 61 (14.3%) remained undiagnosed. MET–PET exhibited high sensitivity (86.2%) but limited specificity (47.4%) for tumor detection. In multiple sclerosis cases, MET–PET showed a remarkably high positivity rate (n = 10/12) that was significantly higher than for other non-tumorous lesions. In terms of tumors, IDH-wildtype glioblastomas had significantly higher TNRs compared to IDH-mutant gliomas, while oligodendrogliomas had higher TNRs compared to astrocytomas, in which TNR values correlated with tumor grade.CONCLUSIONS: MET–PET demonstrated robust sensitivity for brain tumor detection, but was limited by low specificity due to false positives in inflammatory conditions and false negatives for low-grade tumors. These findings imply the importance of integrating MET–PET with other imaging modalities to enhance diagnostic accuracy.ABBREVIATIONS: MET–PET＝11C-methionine positron emission tomography; TNR＝Tumor/normal region ratio; IDH＝isocitrate dehydrogenase.