Abstract
BACKGROUND: The absence of contrast enhancement on magnetic resonance imaging (MRI) characterizes WHO grade II Low-Grade Gliomas. However, up to 30% of non-enhancing lesions are histologically diagnosed as anaplastic gliomas (WHO grade III). Identification of this subset of high-grade non-enhancing gliomas, as well as early detection of malignant transformation is essential in treatment decision. We investigated the role of L-3,4-Dihydroxy-6-[18F]fluorophenylalanine (FDOPA) PET/CT in tumor grading and in the evaluation of early progression in a population of non-enhancing gliomas. MATERIALS AND METHODS: We retrospectively analyzed 22 patients with non-enhancing gliomas (17 grade II, 3 grade III, 2 gliomatosis cerebri). All patients underwent F-DOPA PET/CT in addition to conventional MR surveillance. Static images of the brain were acquired on a Philips Gemini camera over 20 minutes, starting 15 minutes after the i.v. injection of 185 MBq F-DOPA. A low-dose CT scan was adopted for attenuation correction. SUVmax was recorded for all lesions and contralateral background. A tumor to contralateral background uptake ratio (T/B) >1.6 was used as the semiquantitative parameter identifying high grade or early progressive lesions. RESULTS: All non-enhancing lesions showed a T/B >1.1, thus were considered as PET-positive. Median SUVmax was 2.26 ± 1.12. T/B values were suggestive of high-grade and low-grade gliomas in 12 and 10 patients, respectively. All but one patients with T/B 1.6, 2 were gliomatosis cerebri, 4 showed anaplastic transformation within 6 months, 1 was histologically confirmed as grade III non-enhancing glioma, 1 progressed after 18 months. The remaining 4 patients are progression-free after a median of 9 months. CONCLUSION: In patients with non-enhancing gliomas, the presence of high FDOPA uptake is suggestive of high tumor grade (WHO grade III and gliomatosis) or predictive of an early anaplastic transformation. Therefore, FDOPA semiquantitative analysis may be useful to identify a subgroup of patients requiring a short follow-up.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
