Michael Torrens1, Julia Malamitsi2, Pantelis Karaiskos3, Varvara Valotassiou4, Fotis Laspas5, John Andreou5, Christos Stergiou1, Vassilis Prassopoulos4. 1. Department of Radiosurgery and Neurosurgery, Diagnostic and Therapeutic Centre 'Hygeia', Athens, Greece. 2. Department of Medical Physics, Medical School, National and Kapodistrian University of Athens, Athens, Greece j.malamitsi@yahoo.gr. 3. Department of Medical Physics, Medical School, National and Kapodistrian University of Athens, Athens, Greece Department of Medical Physics, Diagnostic and Therapeutic Centre 'Hygeia', Athens, Greece. 4. Department of Nuclear Medicine, Diagnostic and Therapeutic Centre 'Hygeia', Athens, Greece. 5. Department of CT and MRI, Diagnostic and Therapeutic Centre 'Hygeia', Athens, Greece.
Abstract
AIM: To re-evaluate the role of (18)F-fluoro-deoxy-D-glucose (FDG) positron emission tomography/ computer assisted tomography (PET/CT) co-registered with magnetic resonance imaging (MRI) in differentiating adverse radiation effect (ARE) from tumour recurrence after Gamma Knife radiosurgery of brain tumours. PATIENTS AND METHODS: Twenty-seven PET/CT studies co-registered with MRI were performed on 16 patients after radiosurgery, with 12/16 patients having multiple radiosurgery treatments. Long term follow-up was used for evaluation, with 3/16 patients being histopathologically confirmed. RESULTS: PET/CT was positive in all studies in 6/16 patients, negative in all studies in 6/16 and changed from negative to positive in one. In 2/16 patients, PET/CT was both positive and negative in separate tumour foci. In 9/16 cases with a positive PET/CT, tumour was confirmed. In 6/16 patients with a negative PET/CT, 3/6 had recurrence and 3/6 ARE. In 1/16, equivocal results became negative after retreatment. PET/CT/MRI identified tumour within ARE. Sensitivity of PET/CT/MRI proved to be 64.7%, and specificity 100%. CONCLUSION: PET/CT/MRI assists management, by revealing metabolism rather than histology.
AIM: To re-evaluate the role of (18)F-fluoro-deoxy-D-glucose (FDG) positron emission tomography/ computer assisted tomography (PET/CT) co-registered with magnetic resonance imaging (MRI) in differentiating adverse radiation effect (ARE) from tumour recurrence after Gamma Knife radiosurgery of brain tumours. PATIENTS AND METHODS: Twenty-seven PET/CT studies co-registered with MRI were performed on 16 patients after radiosurgery, with 12/16 patients having multiple radiosurgery treatments. Long term follow-up was used for evaluation, with 3/16 patients being histopathologically confirmed. RESULTS: PET/CT was positive in all studies in 6/16 patients, negative in all studies in 6/16 and changed from negative to positive in one. In 2/16 patients, PET/CT was both positive and negative in separate tumour foci. In 9/16 cases with a positive PET/CT, tumour was confirmed. In 6/16 patients with a negative PET/CT, 3/6 had recurrence and 3/6 ARE. In 1/16, equivocal results became negative after retreatment. PET/CT/MRI identified tumour within ARE. Sensitivity of PET/CT/MRI proved to be 64.7%, and specificity 100%. CONCLUSION: PET/CT/MRI assists management, by revealing metabolism rather than histology.