Intravoxel incoherent motion diffusion-weighted MR imaging for differentiation of benign and malignant musculoskeletal tumours at 3 T

Objective: To evaluate the intravoxel incoherent motion (IVIM) diffusion-weighted (DW) MRI for differentiating between benign and malignant musculoskeletal tumours at 3 T. Methods: 65 patients with treatment-naïve musculoskeletal tumours (47 malignant and 23 benign lesions) who underwent 3 T MRI including IVIM DW imaging were included. IVIM-derived parameters included pure diffusion coefcient (D), perfusion related incoherent microcirculation (D∗, pseudodiffusion coefcient), and perfusion fraction (f). IVIM parameters and mono-exponential apparent diffusion coefcient (ADC) were retrospectively measured by two independent musculoskeletal radiologists. Results: D and ADC values of malignant tumours (923 ± 360, 965 ± 353 μm² s^-1, respectively) were signifcantly lower than those of benign tumours (1668 ± 546, 1689 ± 526 μm² s^-1) (p < 0.001). F values of malignant tumours (9.6%) were signifcantly higher than those of benign tumours (7.2%) (p = 0.021), whereas D∗ values showed no signifcant difference (p > 0.05). The area under the receiver operating characteristic (ROC) curve of D, ADC and f were 0.874, 0.880 and 0.671, respectively. Using cut-off values of D and ADC of 1200 μm² s^-1, the sensitivity, specifcity and accuracy were 92, 83, 89%, 92, 87 and 90%, respectively. Conclusion: D and ADC may be more accurate and reliable for differentiation of malignant from benign musculoskeletal tumours than f and D∗ at 3 T IVIM DW imaging. Advances in knowledge: Among IVIM-derived parameters, D is more accurate and reliable in differentiating malignant from benign musculoskeletal tumours than f and D∗ at 3.0T IVIM DW imaging. There was no signifcant difference in the diagnostic performance of D and ADC.