Role of shear wave elastography in differentiating Bland vs tumoral portal vein thrombosis

To evaluate the diagnostic performance of shear wave elastography (SWE) in distinguishing bland from tumoral (malignant) portal vein thrombosis (PVT), using dynamic contrast-enhanced MRI (DCE-MRI) as the reference standard.

A prospective observational study was conducted on patients with ultrasound-confirmed PVT. SWE was performed, followed by DCE-MRI within 48 hours. Mean and median SWE values of the thrombus, liver parenchyma, and any focal hepatic lesions were calculated, and novel SWE ratios (liver-to-PVT and lesion-to-PVT) were derived. At least five RoI measurements were obtained to ensure reliability. Using MRI as the reference standard, diagnostic performance metrics for SWE, including sensitivity, specificity, PPV, NPV, and overall accuracy, were calculated. Fisher's exact test and Chi-square test were used to compare these parameters between bland and tumoral thrombus groups. A p value <0.05 was considered statistically significant.

Fifty patients (mean age: 54.3 ± 10.7 years; 82% males) were included. 16 patients (32%) had bland portal vein thrombosis (PVT), whereas 34 (68%) had tumoral PVT. The mean SWE of PVT was 8.74 ± 4.24 kPa, with significantly lower values in bland PVT (4.63 ± 3.31 kPa) compared with tumoral PVT (10.68 ± 3.11 kPa; p < 0.001). Significant differences were also observed in the ultrasound diameters of the main, right, and left portal veins. The liver SWE/PVT SWE ratio was significantly higher in bland PVT (3.47 ± 3.08 vs. 1.68 ± 0.70; p = 0.033), while the lesion SWE/PVT SWE ratio was higher in tumoral PVT (p = 0.041). ROC analysis showed excellent diagnostic performance of SWE for differentiation of bland versus tumoral thrombus, with AUROC values of 0.903 and 0.915 at cutoff values of ≥6.1 kPa and ≥5.7 kPa for mean and median SWE, respectively.

SWE is a reliable, non-invasive tool for differentiating tumoral from bland PVT, with diagnostic performance comparable to MRI.