title: Searching for the most effective thyrotropin (TSH) threshold to rule-out autonomously functioning thyroid nodules in iodine deficient regions.
abstract: The purpose of this study is to evaluate the distribution of thyrotropin (TSH) values in patients with autonomously functioning thyroid nodules and to set a TSH threshold above which thyroid scintigraphy would be obviated. Four hundred fifty one patients were included in the present study. Inclusion criteria were age > 18 years, TSH levels between 0.40 and 4.0 mIU/L, detection of a single solid or predominantly solid thyroid nodule >10 mm in the longest diameter. Thyroid ultrasound and thyroid scintigraphy with99mTc-pertechnetate were performed concurrently in all patients. Among 451 enrolled patients, 173 (38 %) had an autonomously functioning thyroid nodules, of which 137 (79 %) with a normal TSH level. Demographic data and nodules' volume were not significantly different in patients with autonomously functioning thyroid nodules and non-functioning nodules, respectively. However, TSH levels were nonetheless significantly lower in patients with autonomously functioning thyroid nodules compared to those with non-functioning nodules (p < 0.001). Adopting a TSH cutoff level at 2.38 mUI/L, all autonomously functioning thyroid nodules were correctly identified (i.e., 100 % sensitivity) with a 100 % negative predictive value. Our study showed a very high prevalence of autonomously functioning thyroid nodules in mildly iodine-deficient regions and confirmed that serum TSH is not an effective screening test to diagnose an autonomously functioning thyroid nodules. Our data add arguments in favor of the first-line use of thyroid scintigraphy to assess thyroid nodules, at least in iodine deficient areas. As all scintigraphically detected autonomously functioning thyroid nodules had a TSH level below 2.38 mUI/L, a thyroid scintigraphy should be omitted when higher TSH values are found in patients carrying a thyroid nodule.
authors.affiliation: Deparment of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland. luca.giovanella@eoc.ch.|Thyroid Committee - European Association of Nuclear Medicine, Vienna, Austria. luca.giovanella@eoc.ch.
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
authors.affiliation: Clinical Pathology Laboratory, Department of Laboratory Medicine, General Hospital "Santa Maria degli Angeli", Pordenone, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: D'Aurizio
authors.affiliation: Department of Nuclear Medicine, University Hospital Messina, Messina, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Campenni'
authors.affiliation: Department of Endocrinology Units, University Hospital Messina, Messina, Italy.
authors.forename: Rosaria Maddalena
authors.initials: RM
authors.lastname: Ruggeri
authors.affiliation: Department of Nuclear Medicine, University Hospital Messina, Messina, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Baldari
authors.affiliation: Thyroid Committee - European Association of Nuclear Medicine, Vienna, Austria.|Department of Nuclear Medicine, University Hospital Marburg, Marburg, Germany.
authors.forename: Frederik Anton
authors.initials: FA
authors.lastname: Verburg
authors.affiliation: Deparment of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Trimboli
authors.affiliation: Deparment of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Ceriani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007455:Iodine / Q000172:deficiency*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*; D013972:Thyrotropin / Q000097:blood*; D055815:Young Adult
chemical_list: D013972:Thyrotropin; D007455:Iodine
keywords: Fine-needle aspiration; Scintigraphy; Thyroid nodule; Thyrotropin