A prospective cohort study to assess the role of FDG-PET in differentiating benign and malignant follicular neoplasms

Abstract

BackgroundFollicular and Hürthle cell neoplasms are diagnostic challenges. This prospective study was designed to evaluate the efficacy of [18F]-2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) in predicting the risk of malignancy in follicular/Hürthle cell neoplasms.Materials and methodsFifty thyroid nodules showing follicular/Hürthle cell neoplasm on prior ultrasonography guided fine needle aspiration cytology (FNAC) were recruited into this study. A FDG-PET/CT scan, performed for neck and superior mediastinum, was reported by a single observer, blinded to the surgical and pathology findings. Receiver operating characteristic (ROC) curve analysis of maximum standardized uptake value (SUVmax) and the area under the curve (AUROC) were used to assess discrimination between benign from malignant nodules. Youden index was used to identify the optimal cut-off SUVmax for diagnosing malignancy. Sensitivity, specificity, predictive values and overall accuracy were used as measures of performance.ResultsOur study group comprises of 31 benign and 19 malignant thyroid nodules. After excluding all Hürthle cell adenomas, the AUROC for discriminating benign and malignant non-Hürthle cell neoplasms was 0.79 (95% CI, 0.64–0.94; p = 0.001); with SUVmax of 3.25 as the best cut-off for the purpose. PET/CT had sensitivity of 79% (95% CI, 54–93%), specificity of 83% (95% CI, 60–94%), positive predictive value (PPV) of 79% (95% CI, 54–93%), and negative predictive value (NPV) of 83% (95% CI, 60–94%). The overall accuracy was 81%.ConclusionsFDG-PET/CT can help in differentiating benign and malignant non-Hürthle cell neoplasms. SUVmax of 3.25 was found to be the best for identifying malignant non-Hürthle cell follicular neoplasms.

Performance of 18F-FDG PET/CT in Selecting Thyroid Nodules with Indeterminate Fine-Needle Aspiration Cytology for Surgery. A Systematic Review and a Meta-Analysis

“…Better diagnostic performance values of 18 F-FDG PET/CT are expected in patients with thyroid nodules with a diameter > 1 cm [37,40]; unfortunately, we were not able to perform a subgroup analysis including only patients with thyroid nodules with diameter > 1 cm due to limited data. False positive findings at 18 F-FDG PET/CT were due to nodule composition, with a higher standardized uptake value frequently reported for Hürthle cell adenomas according to the abundant intra-cytoplasmic mitochondria [34,36,39].…”

“…After removal of 113 duplicates, 673 articles were analyzed for title and abstract; 634 records were excluded (guidelines, reviews, meta-analyses, case reports, imaging modalities other than PET/CT (e.g., elastography), tracers other than FDG (e.g., choline), thyroid disease other than thyroid nodule with indeterminate FNA (e.g., thyroid carcinoma, non-diagnostic cytology), not within the field of the review, studies not in humans. The remaining 39 papers were retrieved in full-text and 8 articles were finally included in the systematic review ( Figure 1) [34][35][36][37][38][39][40][41]. No article was added after screening the references of these papers.…”

“…Three studies excluded nodules depending on size or TSH levels, thus patient selection applicability concerns item was rated as high. Particularly, in one study only nodules larger than 10 mm and with a TSH 0.5-4 mUI L −1 were included; in another one, only nodules larger than 5 mm were included; in the last one, only nodules larger than 10 mm and with a TSH 1-4 mUI L −1 were included [36,39,40]. Finally, since we used histology as reference standard, it implies that only surgically removed thyroid nodules were included, possibly leading to a further selection bias.…”

“…Overall, the most important finding is the moderate capacity of this method in discriminating between malignant and benign thyroid nodules with indeterminate FNA, according to the pooled DOR value. [35], Merten [38], Mitchell [34], Muñoz Pérez [37], Nguyen [41], Pathak [39], Piccardo [40]. [35], Merten [38], Mitchell [34], Muñoz Pérez [37], Nguyen [41], Pathak [39], Piccardo [40].…”

Usefulness of accessible imaging methods in thyroid nodules with indeterminate cytology

“…Thus, the sensitivity of 18 FDG-PET in identifying malignant tumors > 1 cm is high (Kresnik et al 2003, Kim et al 2007, Sebastianes et al 2007, Traugott et al 2010, Muñoz Pérez et al 2013, Buyukdereli et al 2016, Pathak et al 2016, Piccardo et al 2016.…”