Diagnostic efficacy of CEUS TI-RADS classification for benign and malignant thyroid nodules

This study aims to evaluate the diagnostic efficacy of a novel system called contrasted enhanced ultrasound thyroid imaging reporting and data system (CEUS TI-RADS) for benign and malignant thyroid nodules. We also seek to assess inter-observer agreement.

The study recruited 433 patients who underwent thyroid ultrasound (US) and CEUS between January 2019 and June 2023 at Affiliated Hospital of Guangdong Medical University. A retrospective analysis of 467 thyroid nodules confirmed by fine-needle aspiration (FNA) and/or surgery was performed. Further, a CEUS TI-RADS classification was assigned to each thyroid nodule based on the CEUS TI-RADS scoring criteria for US and CEUS features of the nodule. The nodules were grouped based on their sizes, i.e., size≤1 cm for Group A, 1 cm < size≤4 cm for Group B, and size > 4 cm for Group C. Multivariate logistic regression was used to analyze independent risk factors for malignant thyroid nodules. Pathological assessment was the reference standard for establishing sensitivity (SEN), specificity (SPE), accuracy (ACC), positive predictive value (PPV), and negative predictive value (NPV) of CEUS TI-RADS for diagnosing malignant thyroid nodules. Receiver operating characteristic curve (ROC) analysis was performed to compare the diagnostic efficacy of the scoring system in predicting malignancy in three groups of nodules. The intragroup correlation coefficient (ICC) was adopted to assess the inter-observer agreement of the CEUS TI-RADS score.

Out of the 467 thyroid nodules, 262 were malignant and 205 were benign. Logistic regression analysis revealed that the independent risk factors for malignant thyroid nodules included punctate echogenic foci (P < 0.001), taller than wide (P = 0.015), extrathyroidal invasion (P = 0.020), irregular margins/lobulated (P = 0.036), hypoechoic (P = 0.038) on US and hypo-enhancement (P < 0.001) on CEUS. The ROC for CEUS TI-RADS diagnosis of malignant thyroid nodules was 0.898 (95% CI:0.867-0.924, P < 0.05) for all nodules, 0.795 (95% CI: 0.721-0.857, P < 0.05) for group A, 0.949 (95% CI: 0.916-0.971, P < 0.05) for group B, and 0.801 (95% CI: 0.644-0.910, P < 0.05) for group C with optimal cut-off values of CEUS TI-RADS 5 points (all nodules), CEUS TI-RADS 6 points (group A), CEUS TI-RADS 5 points (group B), CEUS TI- RADS 5 points (group C), respectively. Among these groups of nodules, group B had the highest ROC, with SEN, SPE, ACC, PPV, and NPV for diagnosing malignant nodules being 95.9%, 88.1%, 92.8%, 92.6%, and 93.2%, respectively. The ICC of the CEUS TI-RADS classification between highly senior and lowly senior physicians was 0.862 (P < 0.001).

In summary, CEUS TI-RADS demonstrated significant efficacy in distinguishing thyroid nodules. Nonetheless, there were variations in its capacity to detect malignant nodules across diverse sizes, demonstrating optimal performance in 1 cm to 4 cm nodules and providing important insights for clinical diagnoses.