Validation of American College of Radiology Bone Reporting and Data System (Bone-RADS) Version 2023 for diagnosis of malignant tumors of appendicular bone on conventional radiographs.

PURPOSE

To evaluate the diagnostic performance of the American College of Radiology(ACR) Bone Reporting and Data System (Bone-RADS) in diagnosis of malignant tumors of the appendicular bone on conventional radiographs.

METHODS

Primary and secondary tumors of appendicular bone in patients who underwent radiographic and MRI examinations were classified into benign, intermediate, and malignant using a reference standard of histopathology, imaging follow-up, or clinical-radiologic consensus. Two radiologists assessed five radiographic features (margin, periosteal reaction, endosteal erosion, pathologic fracture, and extra-osseous mass), scored point total (points from radiographic features and a history of cancer), and assigned Bone-RADS categories. The diagnostic performance of Bone-RADS and interreader agreements were calculated.

RESULTS

A total of 778 patients (507 benign, 45 intermediate, and 226 malignant tumors) were included. Bone-RADS showed high discrimination performance, with areas under the receiver-operating characteristics curve of 0.940-0.957 for point total and 0.895-0.900 for categorization. Bone-RADS had high sensitivity (95.2 %-99.1 %) and negative predictive value (NPV) (96.4 %-99.5 %), but relatively low specificity (65.0 %-68.6 %) and positive predictive value (PPV) (53.7 %-61.9 %). Interreader agreements were good to excellent for Bone-RADS point total (ICC = 0.850), categorization (k = 0.739), and most of the radiographic features (k = 0.621-0.822), except for endosteal erosion (k = 0.537) and extra-osseous mass (k = 0.234).

CONCLUSION

In diagnosis of malignant bone tumors, ACR Bone-RADS showed high discrimination performance, with high sensitivity and NPV, but relatively low specificity and PPV. Nevertheless, relatively low interobserver agreement in some radiographic features and the consensus-based points system in Bone-RADS warrant further research and possible updates.