Positron emission tomography with ([11C]methyl)-L-methionine, [11C]D-glucose, and [68Ga]EDTA in supratentorial tumors.

Sixteen patients with supratentorial tumors were examined with positron emission tomography (PET) using (( /sup 11/C)methyl)-L-methionine, (/sup 11/C)D-glucose, and (/sup 68/Ga)EDTA as well as CT. There were nine astrocytomas (grade II), three oligoastrocytomas (grade II), two anaplastic astrocytomas (grade III), and two meningiomas. Six patients with low-grade astrocytomas and all three patients with oligoastrocytomas had an accumulation of (/sup 11/C)methionine varying from slightly to intensely increased as compared with normal brain tissue. There was a markedly increased uptake of methionine in the anaplastic astrocytomas. Three of the low-grade astrocytomas had a decreased uptake of (/sup 11/C)methionine in at least part of the tumor as compared with normal brain tissue. Contrast enhancement on CT or uptake of (/sup 68/Ga)EDTA was not a prerequisite for increased accumulation of methionine. Uptake of (/sup 11/C)glucose was lower than or equal to that of normal brain tissue in the low-grade tumors and also in one of the two anaplastic astrocytomas and in the bulk of the other. In each individual case the methionine uptake tended to be higher--or less decreased--than the glucose uptake. In the low-grade tumors the uptake of methionine and that of glucose were often different, occasionally markedly different, as far as themore » tumoral-peritumoral areas involved. These differences were even more remarkable in the two anaplastic astrocytomas. An increased uptake of methionine was often seen in areas appearing normal on CT. It appears that PET with (/sup 11/C)glucose has limitations with regard to delineation of the low-grade astrocytomas, whereas PET with (/sup 11/C)methionine usually better reflects the extent of these tumors and, to a lesser degree, the extent of the high-grade neoplasms.« less