Diffusion weighted imaging of extremity bone tumors-inter-reader analysis and incremental value over conventional MR...

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Accurate characterization of osseous tumors is crucial for appropriate patient management.
• Conventional MRI is a primary tool for bone tumor evaluation, but its diagnostic accuracy can be limited.
• Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping offer insights into tissue microstructure.

Purpose of the Study:

• To evaluate the incremental diagnostic value of DWI and ADC maps in characterizing bone tumors.
• To determine if adding DWI to conventional MRI improves diagnostic accuracy for osseous lesions.
• To assess the utility of the DWI/ADC ratio in differentiating benign from malignant bone tumors.

Main Methods:

• A multireader, cross-sectional validation study involving four musculoskeletal radiologists.
• Osseous tumors were evaluated in two rounds: first with conventional MRI, then with the addition of DWI and ADC maps.
• Readers provided binary classifications (benign/malignant), and diagnostic performance metrics, including AUC, were calculated.

Main Results:

• 133 osseous tumors (76 benign, 57 malignant) were analyzed.
• Diagnostic accuracy metrics (sensitivity, specificity, PPV, NPV) remained largely similar with and without DWI.
• Interreader agreement was good in both rounds, and radiologist confidence slightly increased with DWI (p < 0.001).
• ADC values and DWI/ADC ratios showed significant differences between benign and malignant tumors.

Conclusions:

• DWI and ADC parameters demonstrate statistically significant differences between benign and malignant osseous tumors.
• While DWI mildly enhances radiologist confidence, its incremental value in diagnostic accuracy is limited.
• Conventional MRI remains adequate for bone tumor characterization, suggesting limited added benefit from routine DWI use in this context.