title: Clinical significance of thyroid uptake on F18-fluorodeoxyglucose positron emission tomography.
abstract: Significant uptake of the thyroid is often identified as an incidental finding on whole-body F18-fluorodeoxyglucose positron emission tomography (FDG-PET) for non-thyroid disease. Sometimes, it is a dilemma for radiologists to interpret clinical significance of thyroid uptake and give adequate recommendation for further evaluation. In general, diffuse uptake of the thyroid glands on FDG-PET is considered to be benign and very likely secondary to thyroiditis and/or hypothyroidism; a further correlation or investigation of the thyroid function and/or ultrasound is helpful. Focal uptake of the thyroid on FDG-PET is defined as an incidentaloma, which is more clinically significant owing to its high risk of malignancy ranging 25-50%. Although maximum standardized uptake value and corresponding computed tomographic finding may help to differentiate benign from malignant lesion, a cytological diagnosis is often advised. The clinical significance of diffuse plus focal uptake of the thyroid on FDG-PET is not well known; it may also be associated with an increased risk of malignancy when compared with a diffuse uptake pattern only.
authors.affiliation: Nuclear Medicine Service, Department of Radiology, University Hospital, University of Medicine and Dentistry of New Jersey, H-141, 150 Bergen Street, Newark, NJ 07103, USA. liuyl@umdnj.edu
authors.forename: Yiyan
authors.initials: Y
authors.lastname: Liu
mesh_terms: D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D033162:Incidental Findings; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013959:Thyroid Diseases / Q000175:diagnosis*; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000378:metabolism*; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18