Comparison of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography to detect recurrent or residual nasopharyngeal carcinomas after radiotherapy

The diagnostic accuracy of technetium-99m methoxyisobtuylisonitrile (Tc-MIB I) single photon emission computed tomography (SPECT) of head and neck to d ifferentiate between recurrent or residual nasophalyngeal carcinomas (NPC) and benign lesions after radiotherapy was evaluated, and compared with comp uted tomography, (CT). Thirty-six NPC patients 4 months after radiotherapy underwent Tc-MIBI SPECT and CT of head and neck, as well as histopathologic al examination of nasopharyngeal biopsies. Based on the biopsy results, the sensitivity, specificity, and accuracy of CT were 73%, 88%, and 83%, respe ctively. The sensitivity, specificity, and accuracy of Tc-MIBI SPECT were 6 4%, 96%, and 86%, respectively, The sensitivity, specificity, and accuracy of combined Tc-MIBI SPECT and CT were 100%, 88%. and 92%, respectively. Tc- MIBI SPECT had a better specificity and a lower sensitivity to differentiat e benign lesions from recurrent/residual NPC when compared with CT. The com bined use of CT and Tc-MIBI SPECT significantly increased accuracy. compare d with the single use of either Tc-MIBI SPECT or CT to differentiate benign lesions recurrent/residual NPC.