The role of shear wave elastography in differentiation between benign and malignant portal vein thrombosis in hepatocellular carcinoma

Abstract Background Hepatocellular carcinomas (HCC) most commonly complicate liver cirrhosis and it may coexist with malignant portal vein invasion (PVI) that minimizes its possible treatment opportunities and negatively affects its prognosis. However, liver cirrhosis may also be associated with non-tumoral portal vein thrombosis (PVT) particularly in decompensated cirrhosis. Thus, discrimination between tumoral and non-tumoral PVT most preferably by non-invasive imaging techniques is mandatory before treatment decision. Based on the concept of changing tissue elasticity according to tissue pathological changes, Shear wave elastography (SWE) could quantitatively assess tissue stiffness in malignant PVI. We aimed in this work to evaluate the performance of SWE as a novel fast non-invasive diagnostic modality for malignant PVI in cirrhotic patients with HCC. Results Seventy-eight HCC patients with PVT included in this prospective cross-sectional study, tumoral and non-tumoral PVT were differentiated using triphasic CT and/or dynamic MRI, then SWE was blindly and independently done for all included patients. non-tumoral PVT was present in 21.8% of our HCC patients mostly in decompensated cirrhosis. All of our evaluated predictor factors were evaluated by univariate logistic regression analysis to identify the significant factors in prediction of malignant PVI (SWE, AFP, HCC size, HCC multi-focality, and PVD). By using the multivariate logistic regression we identified that the most independent significant factors were SWE and PVD (sig.: 0.012 and 0.045 respectively). SWE was evaluated versus the criteria of PVT and we found that malignant PVI has significant higher SWE values than benign non-tumoral PVT (sig: 0.012). Two cutoff values were calculated for SWE using ROC curve; the 1st cutoff point was selected to rule in malignant PVI for values ≥ 13 kps, while the 2nd cutoff point was selected to rule out malignant PVI for values ≤ 9 kps with a significant discriminatory performance (AUC: 0.984; sig: 0.000). Conclusions SWE could be used as a novel fast and non-invasive indicator of malignant portal vein invasion in cirrhotic patients with HCC especially for values ≥ 13 kps and particularly if coexists with larger values of PVD and AFP.