Thyroid-stimulating hormone-stimulated fused positron emission tomography/computed tomography in the evaluation of recurrence in 131I-negative papillary thyroid carcinoma.

Fluorine-18 2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) detects recurrence of papillary thyroid carcinoma (PTC) in thyroidectomized patients with elevated thyroglobulin (Tg) levels and negative I'll-whole-body scans. This paper describes the utility of thyroid-stimulating hormone (TSH)-stimulated fused FDG-PET/computed tomography (CT) scanning on our first 1.5 patients of this population. Methods: Patients were prepared for PET/CT imaging with thyroid hormone withdrawal (n = 7) or recombinant human TSH (n = 8). All other imaging before the PET/CT did not demonstrate evidence of recurrence. Results: PET/CT scans revealed active foci in 9 patients, 4 prepared with hypothyroidism, and 5 with exogenous TSH. Positive results were demonstrated even in those with relatively low stimulated-TSH Tg values (13 and 14 mu g/L). Six patients with positive PET/CT scans were treated surgically, yielding malignant tissue for 5 of those patients. Conclusion: PET/CT scans performed under TSH stimulation are an effective method of detecting of recurrence of PTC and direct Surgical interventions, even in those with persistently elevated but relatively low Tg levels.