Observer variability in the sonographic evaluation of thyroid nodules.

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Thyroid nodules are common, and accurate characterization is crucial for diagnosis and management.
• Ultrasonography (US) is the primary imaging modality for evaluating thyroid nodules.
• Standardized guidelines are needed to reduce variability in US interpretation.

Purpose of the Study:

• To evaluate inter- and intraobserver variability in the description and diagnostic categorization of sonographic features of thyroid nodules.
• To assess the diagnostic accuracy of the "Guidelines for diagnostic thyroid ultrasonography" proposed by the Thyroid Study Group of the Korean Society of Neuroradiology and Head and Neck Radiology (TSGKSNRHNR).

Main Methods:

• Analysis of US findings for 72 malignant and 61 benign thyroid nodules by five radiologists.
• Two separate analyses were performed at a 6-week interval.
• Inter- and intraobserver variabilities were calculated using Cohen's kappa statistics; sensitivity, specificity, PPV, and NPV were determined.

Main Results:

• Substantial agreement (k=0.64) was observed for internal content (solid vs. cystic).
• Moderate agreement was found for shape, echogenicity, calcification, and diagnostic categories (k=0.42-0.57).
• Fair agreement was noted for margin, echotexture, and capsule invasion (k=0.26-0.34); intraobserver agreement was moderate to substantial for most features.

Conclusions:

• High degrees of inter- and intraobserver agreement were achieved using the TSGKSNRHNR guidelines for thyroid nodule description and categorization.
• The guidelines facilitate consistent and reliable sonographic assessment of thyroid nodules.