Improving diagnostic performance of differentiating ocular adnexal lymphoma and idiopathic orbital inflammation using intravoxel incoherent motion diffusion-weighted MRI

Abstract Purpose To investigate the utility of intravoxel incoherent motion diffusion-weighted MRI (IVIM-DWI) derived diffusion and perfusion parameters in differentiating ocular adnexal lymphoma (OAL) from idiopathic orbital inflammation (IOI), and to assess whether IVIM-DWI provides improved diagnostic performance for the distinction. Method Twenty-one patients with OAL and 24 patients with IOI underwent IVIM-DWI. Apparent diffusion coefficient (ADC) and IVIM-DWI parameters including true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were measured in lesions by two independent radiologists. The MRI parameter differences between OAL and IOI were tested using two-sample t-test. The receiver operating characteristic (ROC) analysis curves were used to determine the diagnostic performance of significant parameters for differentiation between OAL and IOI. Results The ADC, D, and f were lower in OAL than those in IOI (ADC = 0.78 ± 0.12 vs. 0.99 ± 0.16 × 10-3 mm2/s, P  0.05). The combination of D and f provided significantly higher AUC than ADC (AUC = 0.984 vs. 0.838, Z = 2.128, P =  0.033), and had higher sensitivity of 95.24%, specificity of 95.83%, and accuracy of 95.56%. Conclusions IVIM-DWI is valuable in differentiating OAL from IOI, and D combined f can improve the performance of differential diagnosis.