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FIG 3. Patient 4.
A–D, Serial contrast-enhanced gradient-echo images (26/6/1) and PRESS spectra (1000/144/1; voxel resolution, 1.0 cm3) of a cerebellar lesion 1 day before (A) and 3 months (B), 6 months (C), and 8 months (D) after treatment. The most irradiated voxel (almost completely within the red 15-Gy isodose line) received an average dose of 18.0 Gy, while the other three voxels received less than 10 Gy. At the time of radiosurgery low metabolite levels were noted in all voxels. Three months later, metabolite levels had increased, particularly within the radiation target. An increase in Cho is noted posterior to the radiation target at 3 and 6 months after treatment. At 8 months, these spectral abnormalities have become apparent radiologically, while the radiation target shows a necrotic spectrum. The development of a lactate/lipid peak within the high-dose region is also apparent from these serial observations. This patient was treated with gamma knife radiosurgery for a recurrence in the left superior frontal lobe 6 months after the initial treatment, and died 6 months thereafter.
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