Prospective validation of the ultrasound based TIRADS (Thyroid Imaging Reporting And Data System) classification: results in surgically resected thyroid nodules

• Published in: European radiology Vol. 27; no. 6; pp. 2619 - 2628
• Main Authors: Horvath, Eleonora, Silva, Claudio F., Majlis, Sergio, Rodriguez, Ignacio, Skoknic, Velimir, Castro, Alex, Rojas, Hugo, Niedmann, Juan-Pablo, Madrid, Arturo, Capdeville, Felipe, Whittle, Carolina, Rossi, Ricardo, Domínguez, Miguel, Tala, Hernán
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-06-2017; Springer Nature B.V
• Subjects: Adult; Aged; Biopsy; Biopsy - methods; Biopsy, Fine-Needle - methods; Cancer; Classification; Diagnostic Radiology; Female; Hashimoto Disease - diagnostic imaging; Hashimoto Disease - pathology; Hashimoto Disease - surgery; Head and Neck; Humans; Imaging; Internal Medicine; Interventional Radiology; Male; Medicine; Medicine & Public Health; Middle Aged; Neuroradiology; Pathology; Patients; Prospective Studies; Radiology; Risk Assessment; Sensitivity and Specificity; Thyroid gland; Thyroid Neoplasms - pathology; Thyroid Nodule - diagnostic imaging; Thyroid Nodule - pathology; Thyroid Nodule - surgery; Thyroidectomy; Thyroidectomy - methods; Thyroiditis - diagnostic imaging; Thyroiditis - pathology; Thyroiditis - surgery; Ultrasonic imaging; Ultrasonography; Ultrasound; Unnecessary Procedures; Chile; United States > US; Risk classification; Thyroid nodule; Thyroid cancer; Ultrasound; Thyroid neoplasm
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-016-4605-y

Objective
To assess performance of TIRADS classification on a prospective surgical cohort, demonstrating its clinical usefulness.
Methods
Between June 2009 and October 2012, patients assessed with pre-operative ultrasound (US) were included in this IRB-approved study. Nodules were categorised according to our previously described TIRADS classification. Final pathological diagnosis was obtained from the thyroidectomy specimen. Sensitivity, specificity, positive/negative predictive values and likelihood ratios were calculated.
Results
The study included 210 patients with 502 nodules (average: 2.39 (±1.64) nodules/patient). Median size was 7 mm (3–60 mm). Malignancy was 0 % (0/116) in TIRADS 2, 1.79 % (1/56) in TIRADS 3, 76.13 % (185/243) in TIRADS 4 [subgroups: TIRADS 4A 5.88 % (1/17), TIRADS 4B 62.82 % (49/78), TIRADS 4C 91.22 % (135/148)], and 98.85 % (86/87) in TIRADS 5. With a cut-off point at TIRADS 4–5 to perform FNAB, we obtained: sensitivity 99.6 % (95 % CI: 98.9–100.0), specificity 74.35 % (95 % CI: 68.7–80.0), PPV 82.1 % (95 % CI: 78.0–86.3), NPV 99.4 % (95 % CI: 98.3–100.0), PLR 3.9 (95 % CI: 3.6–4.2) and an NLR 0.005 (95 % CI: 0.003–0.04) for malignancy.
Conclusion
US-based TIRADS classification allows selection of nodules requiring FNAB and recognition of those with a low malignancy risk.
Key Points
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TIRADS classification allows accurate selection of thyroid nodules requiring biopsy (TIRADS 4–5)
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The recognition of benign/possibly benign patterns can avoid unnecessary procedures
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This classification and its sonographic patterns are validated using surgical specimens
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