Multifrequency Multiparameter Magnetic Resonance Elastography Applied to an In Vivo Porcine Model for Assessing Portal Hypertension

ABSTRACT Aims Portal hypertension (PH) is a serious complication of chronic liver disease, but its noninvasive assessment remains challenging. This study aimed to evaluate the potential of three‐dimensional magnetic resonance elastography (3D‐MRE) for predicting portal pressure in miniature pig models of PH, using hepatic venous pressure gradient (HVPG) as the gold standard. Methods In 20 male Bama miniature pigs, PH was induced via hepatic arterial embolization, obtaining HVPG measurements and 3D‐MRE scans at baseline and at 4, 8, 12, and 16 weeks post‐induction. Liver and spleen viscoelastic parameters (shear stiffness [SS], storage modulus [SM], loss modulus [LM], and damping ratio [DR]) were acquired by 3D‐MRE at 30/60/90 Hz. After 16 weeks, transjugular intrahepatic portosystemic shunt (TIPS) procedures were undertaken in the PH test pigs. Predictive models for HVPG were developed through stepwise multiple linear regression and evaluated using the area under receiver operating characteristic curve (AUC) values. Results HVPG showed significant independent correlations with splenic SS at 60 Hz ( β = 0.60; p = 0.003), splenic LM at 60 Hz ( β = 1.36; p = 0.020), and splenic SS at 30 Hz ( β = 0.43; p = 0.047). The multifrequency model reliably diagnosed PH (AUC = 0.92, 95% confidence interval [CI]: 0.80–0.98), and predicted HVPGs strongly correlated with actual HVPG measurements ( r = 0.86; p < 0.001), outperforming 90‐Hz MRE ( r = 0.68; p = 0.03) and 30‐Hz MRE ( r = 0.71; p = 0.05). Following TIPS procedures, values of splenic SS at 60 Hz correlated strongly ( r = 0.81; p < 0.001) with changes in HVPG. Conclusion Viscoelastic parameters measured by multifrequency multiparameter 3D‐MRE, particularly splenic SS at 30 and 60 Hz and splenic LM at 60 Hz, proved to be independently associated with HVPG, showing stronger correlations with actual HVPG readings than did single‐frequency determinations.