Differentiation of bland from neoplastic thrombus of the portal vein in patients with hepatocellular carcinoma: application of susceptibility-weighted MR imaging

BACKGROUND: Neoplastic and bland portal vein thrombi (PVT) are both common in patients with hepatocellular carcinoma (HCC). The correct discrimination of them is essential for therapeutic strategies planning and survival predicting. The current study aims to investigate the value of susceptibility-weighted imaging (SWI) in differentiating bland from neoplastic PVT in HCC patients. METHODS: 20 HCC patients with bland PVT and 22 HCC patients with neoplastic PVT were imaged with non-contrast SWI at 3.0 Tesla MRI. The signal intensity (SI) of the PVT and HCC lesions in the same patients was compared on SW images. The phase values of the PVT were compared between neoplastic and bland thrombi cohorts. Receiver operator characteristics (ROC) analysis was conducted to evaluate the diagnostic ability of the phase values for neoplastic and bland thrombi discrimination. RESULTS: 20 of 22 neoplastic PVT were judged similar SI and 2 were judged lower SI than their HCC. For 20 bland PVT, 19 were judged lower SI and 1 was judged similar SI as their HCC (P<0.001). The average phase values (0.361 ± 0.224) of the bland PVT were significantly higher than those of the neoplastic PVT (−0.328 ± 0.127, P<0.001). The AUC for phase values in differentiating bland from neoplastic PVT was 0.989. The best cut-off value was −0.195, which gave a sensitivity of 95% and a specificity of 95.5%. CONCLUSIONS: SW imaging appears to be a promising new method for distinguishing neoplastic from bland PVT. The high sensitivity and specificity suggest its high value in clinical practice.