Clinical Value of Image Fusion from MR and PET in Patients with Head and Neck Cancer

Purpose  This study aimed to evaluate the clinical value of image fusion from magnetic resonance (MR) combined with positron emission tomography (PET) imaging, using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) in head and neck cancer. Methods  Sixty-five consecutive patients underwent MR and FDG-PET scans before or after the treatment of known or suspected head and neck cancer. T1-weighted and T2-weighted images were first assessed by MR interpretation, and then, the fused images of T2-weighted images from MR and PET were evaluated in a blind manner. Diagnostic performance was compared. Procedures  For initial staging, in 48 patients, malignant tumors were histologically confirmed in 45 patients. The interpretation sensitivities of MR alone and fused images for primary tumors were 98% and 100%, respectively. For lymph node metastasis, the sensitivity and specificity of both methods were 85% and 92%, respectively. Of 15 patients with suspected recurrence, ten patients had recurrent tumors, three patients developed second malignant tumors, and two patients had no recurrence. For these patients, the overall sensitivity of MR alone was 67%, whereas that of the fused images was 92%. Eight additional lesions were accurately diagnosed by image fusion only. In two patients with lymph node metastasis from unknown origin, the primary site was not detected in one patient, while tonsilar cancer was identified only by image fusion interpretation. Conclusion  Image fusion from MR with PET might be useful in evaluating head and neck cancer, especially in suspected recurrent cases rather than in fresh cases.