Technetium-99m-MIBI uptake in benign and malignant bone lesions: a comparative study with technetium-99m-MDP.

The potential of hexakis (methoxyisobutylisonitrile) technetium (1) (MIBI) for the imaging of various bone pathologies and for assessment of effectiveness of therapy were investigated in a prospective study. MIBI was evaluated in comparison to MDP bone scans in 73 bone lesions (31 benign, 42 malignant). With MIBI, all but six malignant lesions were clearly visualized and the mean lesion/contralateral (L/C) ratio (2.21 +/- 1.17) was significantly higher than that of benign counterparts (1.26 +/- 0.40) (p less than 0.0005). No such significance was detected on corresponding MDP bone scans (4.86 +/- 3.48 versus 3.11 +/- 1.52). Ten cases with malignant tumor underwent both pre- and post-therapy MIBI evaluation and it was demonstrated that radiotherapy and/or chemotherapy significantly inhibited MIBI uptake. Moreover, post-therapeutic MIBI uptake was a good reflection of the effectiveness of therapy as confirmed by histopathological evaluation. Thus, with a strikingly higher uptake in malignant bone lesions MIBI might have good potential for the detection of malignant bone pathologies as well as for assessing tumor response to therapy.