(99m)Tc-Tetrofosmin brain SPECT in the assessment of meningiomas-correlation with histological grade and proliferation index.

Meningiomas account for about 30% of all intracranial tumors. Evaluation of their proliferation rate is useful for assessing their biological behavior. We evaluated prospectively whether (99m)Tc-Tetrofosmin ((99m)Tc-TF) uptake in meningiomas correlates with cellular proliferative activity and with tumor grade. We prospectively studied 18 meningioma cases. Brain single-photon emission computed tomography (SPECT) by (99m)Tc-TF was performed within a week prior to surgical excision. In the excised tumor specimens we assessed Ki-67 antigen expression. 14 of 18 patients had benign meningiomas, while the remaining four had anaplastic meningiomas. A significant correlation was found between both (99m)Tc-TF uptake and tumor grade (r = 0.722, P = 0.001) and between (99m)Tc-TF uptake and Ki-67 expression (r = 0.930, P < 0.001). There was a significant correlation between the intensity of tracer uptake and tumor recurrence at 1 year postoperative (r = 0.574, P = 0.02). This pilot study implies that (99m)Tc-TF brain SPECT could prove useful in differentiating benign from anaplastic meningiomas and is a potential indicator of their proliferative activity.