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Value of fluorodeoxyglucose positron emission tomography in characterizing clinically‐significant thyroid carcinomas
Author(s) -
Chan Desmond KwanKit,
Lang Brian HungHin,
Law TszTing
Publication year - 2011
Publication title -
surgical practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.109
H-Index - 10
eISSN - 1744-1633
pISSN - 1744-1625
DOI - 10.1111/j.1744-1633.2011.00538.x
Subject(s) - medicine , incidentaloma , malignancy , standardized uptake value , positron emission tomography , radiology , fluorodeoxyglucose , thyroid cancer , thyroid carcinoma , occult , thyroid , nuclear medicine , pathology , alternative medicine
Background: Despite the rising incidence of thyroid incidentalomas, their clinical significance remains unclear. The present study aimed to determine whether fluorodeoxyglucose positron emission tomography (FDG‐PET) is associated with a significantly higher risk of clinically‐significant thyroid carcinoma (CSC) in incidentalomas than other non‐functional imaging modalities. Methods: Over a 2‐year period, 89 patients were identified as having a thyroid incidentaloma. All patients had either surgery or fine needle aspiration cytology (FNAC) with a 12‐month follow up to confirm the nature of the incidentaloma. Surgery was carried out for nodules with malignant or indeterminate FNAC result, or those with in a retrosternal location, with size > 4 cm or local symptoms. Results: A total of 21 (23.6%) patients had their incidentaloma detected by FDG‐PET (PET group) and 68 (76.4%) by non‐PET imaging modalities (non‐PET group). Differentiated thyroid carcinoma was confirmed in 18 (20.2%) patients. The rate of malignancy was 61.9% in the PET group and 7.4% in the non‐PET group ( P = 0.001). After excluding the occult microcarcinomas, the risk of malignancy reduced to 14.6%, but the difference in malignancy rate became more marked between the PET and non‐PET group (42.9% vs 2.9%, P = 0.001). The maximum standardized uptake value on FDG‐PET was similar between benign and malignant lesions ( P = 0.124). Conclusion: The overall risk of CSC in thyroid incidentalomas was 14.6%. Those detected by FDG‐PET were significantly more likely to harbour CSC than those by non‐functional modalities. Incidentalomas with focal FDG uptake should be thoroughly investigated with USG and FNAC.