Clinical Value of 99mTc-3PRGD2 SPECT/CT in Differentiated Thyroid Carcinoma with Negative 131I Whole-Body Scan and Elevated Thyroglobulin Level

The aim of this study was to assess the usefulness of integrin imaging with Tc-99m-PEG(4)-E[PEG(4)- c(RGDfK)](2) (Tc-99m-3PRGD2) single photon emission computed tomography (SPECT)/computed tomography (CT) in detecting recurrent disease in patients with differentiated thyroid cancer (DTC), negative radioiodine whole-body scan (WBS) and high serum thyroglobulin (Tg). Thirty-seven patients who underwent total thyroidectomy followed by radioactive iodine ablation and had negative radioiodine WBS but elevated Tg levels were included. Tc-99m-3PRGD2 SPECT/CT was performed 1 week after the negative diagnostic(131)I WBS. Diagnostic performance indicators, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), for Tc-99m-3PRGD2 SPECT/CT was calculated. The correlations between SPECT/CT results and clinic-pathological characteristics were examined. In 30 (81.1%) of the 37 patients, Tc-99m-3PRGD2 SPECT/CT showed positive uptake. The sensitivity, specificity, PPV, and NPV of SPECT/CT to detect recurrent disease at follow-up were 96.6%, 75%, 93.3% and 85.7%, respectively. The sensitivity and PPV of SPECT/CT increased with increasing serum Tg levels. Tc-99m-3PRGD2 SPECT/CT showed high sensitivity and PPV in the detection of recurrence among DTC patients with hig her Tg levels and negative WBS, and the probability of obtaining a positive SPECT/CT result was related with the level of Tg.