Usefulness of (18)F-FDG PET/CT in Locoregional Recurrence of Differentiated Thyroid Cancer: Comparison PET/CT to PET and Neck Ultrasonography for Biopsy-proven Lesions / 핵의학분자영상

ABSTRACT

PURPOSE: The aim of this study was to investigate the usefulness of (18)F-FDG PET/CT with neck ultrasonography (neck US) in patients with recurrent, papillary thyroid cancer. MATERIAL AND METHODS: This retrospective study (December 2006 to April 2008) enrolled sixty-one patients (ninety-one lesions) who underwent high-dose (131)I-ablation therapy after total thyroidectomy, and evaluated recurred papillary thyroid cancer. All lesions were confirmed by histopathology and compared histopathologic findings to PET, PET/CT, and neck US findings. RESULTS: In sixty-one patients (57 women, 4 men; age range, 24-81 years, mean 49 years; 61 papillary carcinomas), the sensitivity, specificity, accuracy of (18)F-FDG PET/CT was 87.2%, 64.0%, 78.1% on a patient basis and 92.3%, 66.7%, 80.9% on a lesion basis, respectively. The sensitivity, specificity, accuracy of (18)F-FDG PET was 71.8% (p=0.03), 59.0% (p=1.00), 67.2% (p=0.03) on a patient basis and 78.8% (p<0.01), 64.1% (p=1.00), 72.5% (p=0.02) on a lesion basis, respectively. The sensitivity, specificity, accuracy of neck US was 71.1% (p=0.07), 52.2% (p=0.75), 63.9% (p=0.05) on a patient basis and 71.2% (p<0.01), 61.5% (p=1.00), 67.0% (p=0.06) on a lesion basis, respectively. Combined (18)F-FDG PET/CT with neck US improved the sensitivity, specificity, accuracy to 94.7% (p=0.50), 82.6% (p=0.13), 90.2% (p=0.03) on a patient basis and 96.2% (p=0.50), 89.7% (p<0.01), 93.4% (p<0.01) on a lesion basis, respectively. CONCLUSION: (18)F-FDG PET/CT demonstrated significantly higher sensitivity than neck US for the detection of recurred papillary thyroid cancer lesions. Furthermore, combined (18)F-FDG PET/CT with neck US showed more improved sensitivity, specificity, accuracy for diagnosis of recurrent papillary thyroid cancer.