ECE2018 Poster Presentations: Thyroid Thyroid (non-cancer) (105 abstracts)
1University Hospital Arnau De Vilanova, Lleida, Spain; 2Idi-Nuclear Medicine University Hospital Arnau De Vilanova, Lleida, Spain.
Introduction: Up to 30% of the thyroid nodules studied with fine needle aspiration biopsy (FNAB) are reported as Bethesda III, a category that does not rule out malignancy. One technique that could help to decide if there is a surgical indication is (99 m) Tc-sestaMIBI scintigraphy (MIBI).
Material and methods: All patients with a Bethesda III result were prospectively included, and 99 Tc-MIBI scintigraphy was performed prior to surgery. All exams, including ultrasonography, FNAB, cytological diagnosis and scintigraphic exams were perfomed in our hospital. (99 m) Tc-sestaMIBI scintigraphy reports were based on contrast retention at 10 minutes and 3 hours after the radiolabeled compound injection, with gradation of intensity in both moments, considering pathological uptake a moderate-intense retention in any of them. These results were eventually compared with the histological results after surgical intervention.
Results: Eighty-four patients with a 99Tc-MIBI scintigraphy underwent surgery, 68 (80.9%) women, mean age 52.4±13.8 years. 99Tc-MIBI scintigraphies results were reported as benign in 39 (46.4%) and pathological in 45 (53.6%). After surgery 19 (22.6%) cases were reported as thyroid cancer (TC) (12 papillary, 5 follicular and 2 poorly differentiated) and 65 (77.4%) as benign. 38 (58.5%) patients with histological result of benignity did not show pathological uptake in MIBI and 27 (25.6%) did (59,2% at 10 minutes and the rest at both phases). Only one patient with TC (5.3%) did not show a pathological uptake in MIBI. With these results the pathological uptake in MIBI shows a sensitivity of 94.7% and a specificity of 58.5%, with a positive predictive value of 40% and negative predictive value of 97.44%(p <0.001 in chi square test).
Conclusion: We confirm that 99 Tc-MIBI scintigraphy is a useful technique for the identification of benign nodules after the Bethesda III result in cytology with a high negative predictive value. We think that patients with a Bethesda III cytological in a thyroid nodule FNAB and a non pathological MIBI uptake could be undergo clinical follow up without performing surgery.