[Diagnostic values of ultrasound and (18)F-fluoro-2-deoxy-D-glucose-positron emission tomography/computerized tomography for patients with suspected thyroid carcinoma and lymph node metastasis].

Objective: To evaluate the diagnostic values of ultrasound (US) and (18)F-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG PET)/computerized tomography (CT) in diagnosing suspected thyroid carcinoma and lymph node metastasis.

Methods: The clinical data of 28 patients who had undergone total or subtotal thyroidectomy with or without neck dissection from December 2011 to December 2012 in PUMC Hospital and had undergone US and FDG PET/CT before surgery were retrospectively analyzed. In each patient, US and FDG PET/CT images were retrospectively reviewed to determine the presence of carcinoma with or without loco-regional metastasis by level-by-level analysis. The potential correlation between imaging results and histopathology were analyzed.

Results: There were 11 benign lesions,15 papillary carcinomas, one follicular carcinoma, and one medullary carcinoma. For thyroid carcinoma,the sensitivity and specificity were 88.2% and 63.6% for US and 76.5% and 54.5% for FDG PET/CT(P>0.05). For lymph node metastasis, the sensitivity was 68.0% for US and 60.0% for FDG PET/CT (P>0.05), and the specificity was 96.7% for US and FDG PET/CT.FDG PET/CT could provide more diagnostic information than US for patients with level 2 or 5 metastasis.

Conclusions: Combination of US and FDG PET/CT is typically not needed for differentiating thyroid lesions.However, for patients with suspected lymph node metastasis of infrequently involved levels, the combination of US and FDG PET/CT may be a good choice.