Timing of Examination Affects Reliability of 99mTc-Methoxyisobutylisonitrile SPECT in Distinguishing Neoplastic from Nonneoplastic

99mTc-Methoxyisobutylisonitrile (MIBI) SPECT has been re-ported to be 100 % sensitive and specific in the early differential diagnosis between neoplastic and nonneoplastic intraparen-chymal cerebral hemorrhage (ICH), because nonneoplastic ICH does not show 99mTc-MIBI accumulation on SPECT examina-tions performed within 48 h from the onset of clinical symptoms. The aims of this study were to investigate the behavior of nonneoplastic ICH on more delayed 99mTc-MIBI SPECT exam-inations and to determine how the timing of examination affects the reliability of 99mTc-MIBI SPECT in differentiating neoplastic from nonneoplastic ICH. Methods: We prospectively enrolled 32 patients with acute neurologic deterioration caused by non-traumatic ICH. Patients were randomly allocated to 4 groups of 8 patients each. Patients in the first, second, third, and fourth groups underwent 99mTc-MIBI SPECT 2, 5, 10, and 30 d, re