Evaluation of pediatric CNS malignancies with (99m)Tc-methoxyisobutylisonitrile SPECT.

Abstract

SPECT has the potential to add valuable information to the diagnosis and management of central nervous system (CNS) malignancy. Radioactive tracers including (99m)Tc-methoxyisobutylisonitrile (MIBI), or sestamibi, have been shown to be sensitive markers for brain tumors; however, their role in imaging children is poorly defined. We undertook a pilot study of 29 pairs of (99m)Tc-MIBI and MRI images from 20 children to explore the clinical usefulness of this tracer in CNS malignancy. Tumor types that took up (99m)Tc-MIBI included brain stem glioma, fibrillary astrocytoma, other low-grade astrocytomas, and glioblastoma multiforme. Most tumors positive for (99m)Tc-MIBI uptake were astrocytomas, including those in the brain stem, cerebellum, and cortex. This method of nuclear imaging not only was able to identify the presence of a tumor but also could identify changes in the same tumor over time. Some correlation between histologic grade and (99m)Tc-MIBI uptake was observed. Several tumors, including craniopharyngioma, medulloblastoma, and optic glioma, were evident on MRI but not on (99m)Tc-MIBI SPECT. The results suggest that this modality is a potentially useful tool in the diagnosis and management of CNS malignancies, particularly higher-grade astrocytomas, in children.