Diagnostic performances of intravoxel incoherent motion and conventional diffusion-weighted imaging in the differential diagnosis of benign and malignant portal vein thrombus

Abstract

To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) and diffusion-weighted imaging (DWI) parameters in the differential diagnosis of portal vein thrombus (PVT). Thirty-five patients with PVT were enrolled in this retrospective study. Precontrast axial in-phase and out-of-phase T1-weighted (W) turbo field echo (TFE), axial and coronal T2-W single-shot turbo spin echo, IVIM with b values between 0 and 1300 s/mm(2) and conventional DWI with b factors of 50, 400, and 800 s/mm(2) with single-shot echo-planar imaging, and postcontrast dynamic T1-W volumetric interpolated breath-hold examination images obtained with 1.5 T MR unit were evaluated. For quantitative analysis of conventional DWI, an ADC map was reconstructed from conventional DWI using all b values. For quantitative evaluation of IVIM, the SI was calculated from each b value. A specific software program was applied to calculate D (true diffusion coefficient), D* (pseudodiffusion coefficient associated with blood flow), and f (perfusion fraction). The differentiation between benign and malignant PVT was based on the criteria outlined in the study by Catalano et al. (Radiology 254:154-162, 2010). The ADC values of the malignant PVT were significantly lower than those of benign PVTs (p = 0.005). Malignant PVTs had a tendency to show higher f values in comparison with benign PVTs without statistical significance (p = 0.750). The best discriminative parameter was ADC values, which demonstrated a sensitivity of 80.0% and a specificity of 72.7% with cut-off value of 1.00 x 10(-3) mm(2)/s. ADC values might be more superior tool than IVIM parameters in differentiation between malignant and benign PVT.