A 53 y.o. right handed man sought medical attention because of a grand mal seizure. Brain biopsy revealed grade IV astrocytoma. The MR demonstrates an area of mixed signal intensity on proton density (PD) and T2-weighted (T2) images in a right parietal-occipital region. The central rounded core of the lesion is seen after contrast enhancement to contain cystic elements. Glucose metabolism is very low on the first PET study, but has increased three months later. This suggests tumor recurrence, and effectively rules out radiation necrosis.

Like Thallium SPECT, the PET scan has been very useful in differentiating tumor recurrence and radiation necrosis. It also allows specific targeting of the area of recurrence, which may be surrounded by radiation necrosis in those patients who have received radiation.

Case contributed by Drs. C. D. Sturm and R. Bucholz, St. Louis University.

Some details have been altered to protect confidentiality.
Keith A. Johnson (, J. Alex Becker (