Thyroid Incidentalomas detected by 68Ga-DOTANOC PET/CT - Correlation of clinical findings and maximum standardized value uptake (SUVmax)

Aim: In this retrospective study we investigated the clinical relevance of focal increased 68Ga‐DOTANOC uptake in the thyroid gland in patients with no previous history of thyroid disease. The aim was to assess the incidence of malignant disease in these incidental findings and to inspect the potential diagnostic SUVmax ability to differentiate malignant from benign lesions. Material and methods: A total of 954 68Ga‐DOTANOC PET/ CT scans acquired between August 2010 and July 2013 were reviewed and 43 cases were retrospectively studied in which incidental thyroid 68Ga‐DOTANOC increased uptake was reported. Eighteen patients (pts) were excluded due to previous history of thyroid disease. Patients found to have focal thyroid uptake were subsequently correlated with thyroid ultrasonography (US), US‐fine needle aspiration (FNA) cytology or pathology of the specimen from surgical excision. SUVmax of each focal abnormal thyroid uptake was calculated. Results: Thyroid incidentalomas was found by 68Ga‐DOTANOC PET/CT in 2.6% of pts (25/954). Demographics on these 25 pts included 18 women, 7 men, an age range of 36 to 79 years and mean age of 58 years. Five pts did not have clinical follow‐up and of the remaining 20 cases, 2 had an inconclusive FNA citology result and US did not reveal thyroid alterations in other 2. Conclusive diagnosis by US‐FNA cytology or pathology of the specimen was available in 16 cases: 7 (44%) revealed malignant lesions (SUVmax: 2.36 to 9.63; average: 6.10; median: 6.22) corresponding to six well‐differentiated papillary carcinoma and one case of secondary lesion, 9 (56%) were benign nodules (SUVmax: 2.59 to 11.59; average: 6.46; median: 6.27). No statistically significant difference was found between SUVmax of benign and malignant lesions (p=0.918, Mann‐ Whitney test). Conclusion: Our results showed that focal thyroid uptake in 68Ga‐DOTANOC PET/CT was related to a high incidence of malignancy (44%), which suggests that these findings should always be reported and investigated. In our study, SUVmax was not a reliable mean to differentiate malignancy from a benign process, but a larger sample is needed to further validate this statement.

URI

http://hdl.handle.net/10198/17726

Citation

Violante, L.C. Sobral; Teixeira, J.P.; Sampaio, I.L.; Duarte, A.; Soares, O.; Lopes, F.; Costa, L.; Fonseca, A.; Couto, J.; Duarte, H. (2014). Thyroid Incidentalomas detected by 68Ga-DOTANOC PET/CT - Correlation of clinical findings and maximum standardized value uptake (SUVmax). In Annual Congress of the European-Association-of-Nuclear-Medicine (EANM). Gothenburg, Swedem