Thyroid incidentalomas identified by 18F-FDG PET: sonographic correlation.
ABSTRACT The purpose of this study was to evaluate the risk of malignancy of thyroid incidentalomas detected on (18)F-FDG PET and the diagnostic accuracy of sonography for differentiating benign from malignant focal thyroid incidentalomas that were detected on FDG PET.
Retrospective review was performed of a database of 87 focal thyroid lesions seen on FDG PET and sonography. Forty-two focal lesions were malignant. We compared the accuracy of the maximum standard uptake value (SUV) to differentiate benign from malignant thyroid lesions. We classified the thyroid nodules as probably benign or suspicious for malignancy by the sonographic features. Statistical analyses compared two subgroups by sonographic classifications between benign and malignant thyroid lesions.
The maximum SUV of the malignant nodules was not significantly higher than that of benign lesions. Thirty-seven (75.5%) of 49 lesions with suspicious sonographic findings revealed malignancy on cytopathology, compared with five (13.2%) of 38 lesions that showed probably benign sonographic findings. These differences were statistically significant using a kappa test (kappa = 0.675, p = 0.001) and logistic regression (odds ratio = 26.2, p = 0.001).
The probability (48.3%) of malignancy of focal thyroid incidentalomas seen on FDG PET is high. The maximum SUV of thyroid cancer is not significantly higher than that of benign lesions. The probability (13.2%) of malignancy is much lower when the sonographic findings appear benign, as compared with a significantly higher probability (75.5%) of malignancy when the sonographic findings are suspicious for malignancy.
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ABSTRACT: Context:Thyroid incidentaloma diagnosed by 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (F-18-FDG-PET/CT) is defined as a thyroid uptake incidentally and newly detected in a patient studied for nonthyroid purpose. In this review, we have comprehensively analyzed the diagnostic and clinical significance of F-18-FDG-PET/CT thyroid incidentalomas revealed during studies performed for an unrelated and nonthyroid purpose.Evidence Acquisition:A comprehensive literature research of the PubMed/MEDLINE databases was conducted to find relevant published articles about the F-18-FDG-PET or F-18-FDG-PET/CT thyroid incidentalomas.Evidence Synthesis:All studies considered in this review have investigated a very large number of patients, achieving overall about 147,505 units. The pooled incidence of thyroid incidentalomas detected by F-18-FDG-PET or PET/CT was 2.46% (95% confidence interval, 1.68-3.39%). The malignancy ratio was 34.6% (95% confidence interval, 29.3-40.2%).Conclusion:F-18-FDG-PET/CT thyroid incidentaloma is a relevant clinical finding; diffuse uptakes and most focal uptakes are commonly caused by benign diseases, whereas about one third of focal uptakes are malignant; the most frequent malignant histological type responsible for F-18-FDG-PET/CT thyroid incidentaloma is papillary thyroid carcinoma.The Journal of clinical endocrinology and metabolism 08/2012; · 6.50 Impact Factor
Article: F18-FDG-PET/CT thyroid incidentalomas: a wide retrospective analysis in three Italian centres on the significance of focal uptake and SUV value.[show abstract] [hide abstract]
ABSTRACT: Thyroid incidental uptake is defined as a thyroid uptake incidentally and newly detected by imaging techniques performed for an unrelated purpose and especially for non-thyroid diseases. Aim of the study was to establish the prevalence and pathological nature of focal thyroid incidentalomas detected at F18-FDG-PET/CT in patients studied for oncological purposes and not for thyroid disease. Secondary end point was to establish a possible maximum standardised uptake value cut-off over which a malignant lesion should be suspected. We have retrospectively evaluated 49519 patients who underwent F18-FDG-PET/CT for oncologic purposes in three Nuclear Medicine Centres (N.1 = 11278, N.2 = 31076, N.3 = 7165). A focal incidental thyroid uptake was diagnosed in 729 (1.5 %) patients (287-39.4 % male and 442-60.6 % female; average age: 65.26). Of 729 thyroid incidentalomas 211 (28.9 %) underwent further investigation to determine the nature of the nodule; 124/211 (58.8 %) incidentalomas were benign, 72/211 (34.1 %) malignant, 4/211 (1.9 %) non-diagnostic at cytological examination in the absence of surgery and histological evaluation and 11/211 (5.2 %) were indeterminate at cytological examination. A centre-based receiver operating curve (ROC) analysis of the patients with a definitive diagnosis was performed to identify a SUVmax cut-off useful in differentiating benign from malignant incidentalomas. In the centre N.1 it was 4.8 (sensitivity = 95.7 %, specificity = 46.4 %, area under the curve = 0.758); 5.3 in the centre N.2 (sensitivity = 76.3 %, specificity = 72.5 %, area under the curve = 0.815); 7 in the centre N.3 (sensitivity = 57.1 %, specificity = 79.3 %, area under the curve = 0.627). F18-FDG-PET/CT thyroid incidentalomas are a relevant diagnostic reality which requires further investigations and clinical management especially considering that, despite mainly benign, approximately one third of focal thyroid uptakes are malignant.Endocrine 11/2012; · 1.42 Impact Factor