Apparent diffusion coefficient can assist in differentiating between benign and malignant primary bone tumors in...

To evaluate differences in apparent diffusion coefficient (ADC) values between benign and malignant primary pediatric bone tumors and to assess their diagnostic accuracy in differentiating these tumors.

We retrospectively analyzed MRI scans of 96 pediatric patients (54 males, 42 females; mean age 12.97 ± 3.9 years) with primary bone tumors who underwent diffusion-weighted imaging, including 48 benign and 48 malignant tumors. We measured ADCmean, ADCmin, and ADCmax of the solid tumor part, carefully avoiding cystic, necrotic, or sclerosed tumor areas. The Wilcoxon rank-sum test was used to test the distributional difference of benign vs malignant tumors. ROC curve analysis was performed to assess the diagnostic accuracy. The optimal cutoff of ADC values to differentiate benign and malignant bone tumors was defined as the point at which the Youden index, the sum of sensitivity and specificity, was maximized.

The median values of the ADCmean, ADCmin, and ADCmax for benign bone tumors [1.34 (1.13-1.83), 0.98 (0.73-1.34), and 1.80 (1.57-2.46) × 10^-3mm²/s, respectively] were significantly higher compared to malignant bone tumors [0.93 (0.78-1.03), 0.59 (0.43-0.72), and 1.35 (1.22-1.66) × 10^-3mm²/s, respectively; all p < 0.05]. ADCmean yielded the highest diagnostic accuracy, with an optimal cutoff of 1.04 (0.94-1.15) × 10^-3mm²/s (sensitivity 77%, specificity 93%, AUC = 0.91). An ADCmin cutoff of 0.82 (0.65-0.98) × 10^-3mm²/s resulted in a sensitivity of 87.5%, specificity of 70.0%, and AUC of 0.85. An ADCmax cutoff of 1.48 (1.18-1.78) × 10^-3mm²/s achieved a sensitivity of 68%, specificity of 81%, and AUC of 0.80.

ADCmean, ADCmin, and ADCmax differ significantly between benign and malignant pediatric bone tumors, and the ADCmean provides the highest diagnostic accuracy.