TECHNETIUM-99M-MIBI IN PRIMARY AND RECURRENT HEAD AND NECK TUMORS - CONTRIBUTION OF BONE SPECT IMAGE FUSION

We prospectively investigated 200 patients with the clinical suspicion for head and neck tumors. The final diagnoses were 94 primary and 56 (37 confirmed, 19 excluded) recurrent squamous cell carcinomas (SCCs), 3 primary and 7 (4 confirmed, 3 excluded) recurrent adenoid cystic ca rcinomas (ACCs), 6 non-Hodgkin's lymphomas, 10 distant metastases, 6 o ther malignancies, 10 inflammatory and 8 other nonmalignant conditions . Methods: Bone (600 MBq Tc-99m-3,3-diphosphono-1,2-propane dicarboxyl ic acid tetrasodium salt) and hexakis-2-methoxyisobutyl isonitrile (MI BI) (600 MBq Tc-99m-MIBI) SPECT were both performed under identical co nditions (triple-head gamma camera; ultra-high-resolution, parallel-ho le collimators; three-dimensional postfiltering) and judged independen tly and after superimposition. The results were compared to the result s of biopsy, surgery and CT. Results: The overall sensitivity/specific ity of MIBI was 90%/78% for tumor detection and 90%/95% for the identi fication of malignant lymph node involvement (CT: 79%/66%, respectivel y 90%/79%). In the subgroup of recurrent SCC and ACC the sensitivity/s pecificity for tumor detection was 95%/71% for MIBI versus 78%/68% for CT. The isolated assessment of bone SPECT had a sensitivity/specifici ty of 100%/170% for osseous tumor spread, Image fusion of MIBI and bon e SPECT differentiated between regio-local bone involvement and inflam matory changes and increased the specificity of bone SPECT to 100% in primary staging. Tumor size, stage, histology and pretreatment had no statistically significant effect on tracer uptake or diagnostic utilit y of scintigraphy, Conclusion: We propose the combined Tc-99m-MIBI and bone ultra-high resolution SPECT as a highly useful imaging approach in the primary and secondary staging in patients with suspected malign ancies in the head and neck region. The high specificity for malignanc ies in the head and neck region may be used in the differential diagno sis between head and neck malignancies and inflammatory disease in pat ients with the accidental finding of enlarged lymph nodes and no clini cal signs of a primary tumor. Image fusion with bone scanning is manda tory for the topographical orientation and increases the specificity o f bone scanning to differentiate between inflammatory or malignant cau ses of increased bone metabolism.