Quantitative classification and radiomics of [18F]FDG-PET/CT in indeterminate thyroid nodules

Abstract

Purpose To evaluate whether quantitative [18F]FDG-PET/CT assessment, including radiomic analysis of [18F]FDG-positive thyroid nodules, improved the preoperative differentiation of indeterminate thyroid nodules of non-Hürthle cell and Hürthle cell cytology. Methods Prospectively included patients with a Bethesda III or IV thyroid nodule underwent [18F]FDG-PET/CT imaging. Receiver operating characteristic (ROC) curve analysis was performed for standardised uptake values (SUV) and SUV-ratios, including assessment of SUV cut-offs at which a malignant/borderline neoplasm was reliably ruled out (≥ 95% sensitivity). [18F]FDG-positive scans were included in radiomic analysis. After segmentation at 50% of SUVpeak, 107 radiomic features were extracted from [18F]FDG-PET and low-dose CT images. Elastic net regression classifiers were trained in a 20-times repeated random split. Dimensionality reduction was incorporated into the splits. Predictive performance of radiomics was presented as mean area under the ROC curve (AUC) across the test sets. Results Of 123 included patients, 84 (68%) index nodules were visually [18F]FDG-positive. The malignant/borderline rate was 27% (33/123). SUV-metrices showed AUCs ranging from 0.705 (95% CI, 0.601–0.810) to 0.729 (0.633–0.824), 0.708 (0.580–0.835) to 0.757 (0.650–0.864), and 0.533 (0.320–0.747) to 0.700 (0.502–0.898) in all (n = 123), non-Hürthle (n = 94), and Hürthle cell (n = 29) nodules, respectively. At SUVmax, SUVpeak, SUVmax-ratio, and SUVpeak-ratio cut-offs of 2.1 g/mL, 1.6 g/mL, 1.2, and 0.9, respectively, sensitivity of [18F]FDG-PET/CT was 95.8% (95% CI, 78.9–99.9%) in non-Hürthle cell nodules. In Hürthle cell nodules, cut-offs of 5.2 g/mL, 4.7 g/mL, 3.4, and 2.8, respectively, resulted in 100% sensitivity (95% CI, 66.4–100%). Radiomic analysis of 84 (68%) [18F]FDG-positive nodules showed a mean test set AUC of 0.445 (95% CI, 0.290–0.600) for the PET model. Conclusion Quantitative [18F]FDG-PET/CT assessment ruled out malignancy in indeterminate thyroid nodules. Distinctive, higher SUV cut-offs should be applied in Hürthle cell nodules to optimize rule-out ability. Radiomic analysis did not contribute to the additional differentiation of [18F]FDG-positive nodules. Trial registration number This trial is registered with ClinicalTrials.gov: NCT02208544 (5 August 2014), https://clinicaltrials.gov/ct2/show/NCT02208544.

Radiomics in Oncological PET Imaging: A Systematic Review—Part 1, Supradiaphragmatic Cancers

“…Six studies were available for thyroid tumors [ 222 , 223 , 224 , 225 , 226 , 227 ], all using 18F-FDG. The average number of patients was 89.0 (range 55–123); 3/6 (50.0%) studies included more than 100 patients, 1 was prospective and 1 used a validation cohort.…”

“…Among them, 3/6 (50.0%) studies focused on 18F-FDG thyroid incidentalomas, 2 studies were interested in risk stratification in indeterminate thyroid nodules. The only study with a QS above 3, a prospective study of 123 patients conducted by de Koster et al [ 225 ], reported no added value of radiomics for that purpose in 18F-FDG positive nodules.…”

Global thyroid cancer incidence trend and age-period-cohort model analysis based on Global Burden of Disease Study from 1990 to 2019

“…Previous studies used outdated data to explore the incidence of TC, while GBD 2019 provided the latest population-based cancer registration data, which estimated the burden of 285 diseases and disabilities using a uniform and standardized approach. This study will compare the data of different countries/regions and different periods through GBD 2019 in order to provide data support for the rational allocation of medical resources and the establishment of prevention and screening system ( 7 ).…”

Radiomics in [18F]FDG PET/CT: A leap in the dark?

“…Pathak et al reported a SUV max cut-off of 3.25 g/mL best differentiated 42 non-Hürthle cell nodules with 79% sensitivity and 83% specificity [297]. An additional analysis of the EfFECTS trial dataset assessed the added value of SUV metrics, SUV-ratios (node to contralateral normal thyroid) and radiomics for the preoperative differentiation [293].…”

“…None of these previous studies used ROC curve analysis to determine SUV cut-offs that corresponded to optimal test sensitivity, i.e., a NPV similar to a benign cytologic diagnosis (i.e., 96.3%) as per the ATA recommendations for a useful rule-out test [205]. De Koster et al performed quantitative analysis and ROC curve analysis of the EfFECTS dataset, including 123 patients who underwent [ 18 F]FDG PET/CT according to the EANM guidelines [293]. Quantitative [ 18 F]FDG PET/CT assessment ruled out malignancy in indeterminate thyroid nodules, optimising the rule-out ability when distinctive SUV cut-offs were applied to Hürthle and non-Hürthle cell nodules.…”