Interpretation of scintigraphic findings of oral malignant tumours with a new scanning agent of technetium-99m- hexakis-2-methoxy-isobutyl-isonitrile (Tc-99m-MIBI).

Objectives: The purpose of this study was to investigate the usefulness of a new scanning agent of technetium-99m-hexakis-2-methoxy-isobutyl-isonitrile (Tc-99m-MIBI) for the diagnosis of malignant tumours of the head and neck. Methods: Scintigraphy with Tc-99m-MIBI was performed in 19 patients with malignant turnouts of the head and neck. Factors of the early and delayed static scans (hot, warm or cold uptake), the early and delayed retention indexes, the blood flow index and the tumour retention index were obtained from Tc-99m-MIBI scintigraphy. Tumour retention indexes were classified into three grades; slightly (>0.9), moderately (0.9–0.8) and severely (0.8 >) decreased. Grade of tissue differentiation of tumour (well, moderately or poorly differentiated) and tumour size (T1 ∼ T4) were examined using the excised turnout. Scintigraphic indexes and tumour characteristics were compared. Results: The early static scan and tumour size showed a correlation with the blood flow index. However, the delayed static scan did not show any relationship with blood flow index and tumour size. The tumour retention index had a tendency to decrease in malignant turnouts, and showed a significant correlation with the grade of tissue differentiation of the tumour. Conclusions: The tendency of the tumour retention index to decrease in Tc-99m-MIBI scintigraphy showed the malignancy of tumour and would be useful for the diagnosis of malignant tumours of the head and neck. [ABSTRACT FROM AUTHOR]