Detection of Recurrent Nasopharyngeal Carcinomas with Technetium-99m Methoxyisobutylisonitrile Single Photon Emission Computed Tomography in Patients with Indeterminate Magnetic Resonance Imaging Findings after Radiotherapy

The aim of this study was to evaluate the effectiveness of technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) for detecting recurrent nasopharyngeal carcinomas (NPCs) when magnetic resonance imaging (MRI) findings are indeterminate. Twenty-eight NPC patients who had received radiotherapy and had indeterminate MRI findings were included in the study. We performed MRI, Tc-99m MIBI SPECT, and biopsy at least 4 months after radiotherapy and within 1 week. The final results were based on histopathologic findings and clinical follow-up after 6 or more months. For detecting recurrent NPC in indeterminate MRI findings, the sensitivity, specificity, and accuracy of Tc-99m MIBI SPECT were 85.7%, 92.9%, and 89.3%, respectively. Our findings suggest that Tc-99m MIBI SPECT may be an effective tool for detecting recurrent NPC when MRI findings are indeterminate.