The increasing role of PET-CT in oncological and non-oncological conditions has resulted in an increased detection of PET-CT incidentalomas, commonly involving the thyroid gland [1, 2 and 3]. The tracer 18-Fluorodeoxyglucose(18F-FDG) used in PET-CT can incidentally accumulate in the thyroid gland, either diffusely or focally. Incidental focal 18F-FDG uptake within thyroid gland has previously been found to occur in 1.2–4.3% of all PET-CT scans in patients scanned for an alternative indication [4, 5, 6, 7, 8, 9, and 11]. Patients with focal uptake within thyroid...

This is a retrospective study of all 18F-FDG PET-CT scans performed in a large teaching hospital between June 2010 and May 2019. We performed a CRIS (CDN Radiology Information System) database search and results filtered to include the word “thyroid” within the scan reports. All 18F-FDG PET-CT scans in our institution are double reported by four experienced Consultants, two of whom are also experienced in routine thyroid imaging. Studies with no thyroid uptake were excluded. We manually collected patient’s data including age and gender, primary...

Six thousand, one-hundred and seventy-nine (n=6179)18F-FDG PET scans were performed during study period. Three-hundred and forty-two (n=342) results contained word “thyroid” of which two-hundred and seventy (n=270) scans had increased uptake in thyroid gland. Eighty-seven (n=87) patients were excluded leaving a study group of one-hundred and eighty-three (n=183). Ninety-four (n=94) PET-CT scans had focal uptake and eighty-nine (n=89) had diffuse uptake. In those with focal uptake, twenty-five (n=25) patients had pathology results and fifty-two percent (52%, n=13/25) of these FNA biopsies confirmed malignancy. Thyroid malignancy...

Standardised approach needed for investigation of incidental 18F-FDG PET-CT focal uptake in thyroid gland due to high prevalence of malignancy and a combination of ultrasound with FNAC is advised. There is conflicting evidence at how to utilize SUVmax in focal thyroid tracer uptake but its use in combination with ultrasound and histopathological findings should be sought with further bigger studies. We established that SUVmax is relatively higher in follicular carcinoma than papillary carcinoma however further research in large patient groups is needed.

S. Roddy; Dundee/UK - nothing to disclose T. J. Biggans; Dundee/UK - nothing to disclose A. K. Raofi; Dundee/UK - nothing to disclose A. K. Kanodia; Perth/UK - nothing to disclose T. A. P. Sudarshan; Dundee/UK - nothing to disclose P. Guntur; Dundee/UK - nothing to disclose

1.The Royal College of radiologists. iRefer: Making the best use of clinical radiology, 7th edition. London: The Royal college of Radiologists, 2012. 2.Delivanis D.A., Castro M.R. (2018). Thyroid Nodules.Humana Press; Cham, Switzerland: 2017. Thyroid Incidentalomas; pp. 153–167. 3.Vassiliadi D.A., Tsagarakis S. Endocrine Incidentalomas—Challenges Imposed by Incidentally Discovered Lesions.National review of endocrinology, 2011; June 28th; 7:668–680. Doi: 10.1038/nrendo.2011.92 4. Kao YH, Lim SS, Ong SC, Padhy AK. Thyroid incidentalomas on fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography: Incidence, malignancy risk, and comparison of standardized uptake values. Cancer Associated...