Magnetic Resonance Imaging in Evaluation of Bone Tumor Matrix: Diagnostic Value and Matrix Characteristics

Objective: Plain radiographs are vital for initial evaluations of bone tumors. However, multiplanar imaging; like magnetic resonance imaging (MRI), is often necessary for inconclusive cases. Hence, we aimed to determine the diagnostic value of MRI in evaluating bone tumor matrix and analyzing MRI characteristics of the matrix.Material and Methods: This study reviewed 245 MRI and plain radiographs of pathologically confirmed bone tumors; including 123 mineralized and 122 non-mineralized bone tumors. A radiologist having 16 years of experience assessed tumor matrix characteristics, including border, signal intensity on T1-weighted (T1W), T2-weighted (T2W), and gradient-echo images, along with enhancement patterns. Sensitivity, specificity, and a 95% confidence interval were used to present diagnostic values.Results: MRI demonstrated a sensitivity and specificity of 78.1% and 87.7% in differentiating mineralized from non-mineralized matrices, compared to 75.6% and 92.6% for plain radiographs. Both modalities showed high sensitivity and specificity in evaluating osteoid and chondroid matrices (MRI: 80.3%/84.0%, 94.5%/96.8%; radiographs: 80.3%/72.0%, 95.1%/96.4% specificity). High specificity was noted in evaluating fibrous matrices (97.4%/99.6%) but with low sensitivity (23.5%/11.8%). MRI outperformed radiographs in subcategorizing fat, soft tissue, and cystic tumors. The chondroid matrix exhibited distinct characteristics on MRI (well-defined lobulated border with high/intermediate T2W and lobulated/peripheral enhancement), while osteoid and fibrous matrices showed similar features, except in T1W signal intensity. Non-mineralized tumors displayed varied characteristics.Conclusion: While plain radiographs are essential for initial bone tumor assessment, especially for mineralization, MRI is superior in evaluating tumor matrices and non-mineralized tissues in providing detailed characterization for staging and treatment planning.