Comparison of ^sup 131^I whole-body imaging, ^sup 131^I SPECT/CT, and ^sup 18^F-FDG PET/CT in the detection of metastatic thyroid cancer

The aim of this study was to compare ^sup 131^I whole-body scintigraphy (WBS), WBS with ^sup 131^I single photon emission computed tomography/computed tomography (SPECT/CT), and ^sup 18^F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the detection of distant metastases of differentiated thyroid cancer (DTC). A total of 140 patients with 258 foci of suspected distant metastases were evaluated. ^sup 131^I WBS, ^sup 131^I SPECT/CT, and ^sup 18^F-FDG PET/CT images were interpreted separately. The final diagnosis was obtained from histopathologic study, serum thyroglobulin level, other imaging modalities, and/or clinical follow-up. Of the 140 patients with 258 foci, 46 patients with 166 foci were diagnosed as positive for distant metastasis. The sensitivity, specificity, and diagnostic accuracy of each imaging modality were 65, 55, and 59%, respectively, for ^sup 131^I WBS; 65, 95, and 85% for ^sup 131^I SPECT/CT, respectively; and 61, 98, and 86%, respectively, for ^sup 18^F-FDG PET/CT in patient-based analyses. Lesion-based analyses demonstrated that both SPECT/CT and PET/CT were superior to WBS (p