Technetium-99m-MIBI SPECT in Intracranial Lesions

ABSTRACT

Thallium(T1) has recently been used as a pharmaceutical for tumor imaging and staging. The aim of this study was to evaluate the clinical significance of the T1 analogue, 99m-Tc-MIBI(methoxyisobutylisonitrile), for imaging of intracranial lesions. The advantages of MIBI were though to be a lower radiation exposure and better image quality than with T1. 99m-Tc-MIBI SPECT studies were done in 30 patients with brain tumors(14 astrocytomas, 7 meningiomas, 2 hemangioblastomas, 2 craniopharyngiomas, 1 ependymoma, 4 metastatic tumors) and in twelve patients with non-tumorous lesions(2 abscesses, 2 granulomas, 2 cysticercosis, 3 old intracerebral hemorrages, 1 infarction. 1 postoperative gliosis, 1 unknown pathology), and semiquantitative assessment of tracer uptake was made using a ratio of radioactivity for lesion to contralateral normal brain(Lesion/Contralateral normal brains ; L/C). Twenty six of thirty tumors showed high L/C ratios(>1.5) and another four tumors low L/C ratios(<1.5). Of 12 non-tumorous intracranial lesions, 11 showed little or no uptake, but one moderate uptake. In conclusion, it appears that brain tumors show more intense focal uptake than non-tumorous brain lesions. However, further studies would be warranted to evaluate the clinical significance of MIBI SPECT in tumor staging(grading) and in differentiating necrosis from tumor regrowth more clearly.