Differentiation of Cerebral Radiation Necrosis from Tumor Recurrence in Patients with Malignant Gliomas Using 18F-FDG Positron Emission Tomography.

Jung, Hee Won; Paek, Sun Ha; Kim, Dong Gyu

Original Article

Journal of Korean Neurosurgical Society 1997;26(2): 165-172.

Hee Won Jung, Sun Ha Paek, Dong Gyu Kim

¹Department of Neurosurgery, Seoul National University, College of Medicine, Seoul, Korea.
²Department of Neurosurgery, Gyeongsang National University, College of Medicine, Chinju, Korea.

ABSTRACT

The authors evaluated the usefulness of the positron emission tomography(PET) with fluorine-18-fluorodeoxy-glucose(18F-FDG) in diagnosing tumor recurrence and differentiating it from radiation necrosis following external beam irradiation of malignant gliomas. Patients were studied from the time they had first exhibited either clinical or radiological deterioration after an initial period of posttreatment stabilization. Ten studies were performed in ten patients, and 18F-FDG uptake by the lesion was then compared to uptake by adjacent normal gray matter. Four of ten cases demonstrated newly enhanced lesions on magnetic resonance imaging(MRI) and hypermetabolic foci in the PET examinations. All of these patients were diagnosed as tumor recurrence either clinically or histologically, during follow up period of the patients' progress. The remaining six cases had newly enhanced lesions on MRI and hypometabolic foci in the PET studies; five of them were diagnosed as radiation necrosis, but one lesion (0.8cm in diameter) was diagnosed clinically as a tumor recurrence. The overall accuracy of the PET study in differentiating the tumor recurrence from radiation necrosis was 90% and the sensitivity for detection of recurrence 80%. The authors conclude that the PET study with 18F-FDG is useful in differentiating the tumor recurrence from radiation necrosis in patients with malignant glioma and could be used to select the group of patients who may have benefits from antitumor therapy.

Key Words: 18F-FDG PET; Recurrence; Radiation necrosis; Malignant glioma