THE ROLE OF MAGNETIC-RESONANCE-IMAGING AND SCINTIGRAPHY IN THE DIAGNOSIS OF PATHOLOGICAL-CHANGES OF THE MANDIBLE AFTER RADIATION-THERAPY

A prospective study of 85 patients with oral cancer, treated with high -dose radiation therapy, was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radia tion osteomyelitis occurred in 12 cases, tumor recurrences infiltratin g the mandible in five cases, and progressive periodontal disease in n ine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigrap hy with Tc-99m-HDP, all alterations of the mandible, such as osteoradi onecrosis, tumor infiltration, and periodontitis, showed a high uptake , resulting in a sensitivity of up to 100%, but a low specificity of 5 7%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography a nd clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy. (C) Munksgaard 1996.