In this study we investigate the ability of MR elastography (MRE) and ultrasound shear wave elastography (SWE) to assess portal hypertension (PH) severity in patients with liver disease and hepatic venous pressure gradient (HVPG) measurement. 3D MRE spleen stiffness correlated with HVPG. 2D and 3D MRE of the spleen were significantly higher in patients with clinically significant PH (CSPH, HVPG>10mmHg) than those with no PH/PH (HVPG>5mmHg). 3D MRE spleen stiffness was significantly elevated in PH/CSPH patients compared to those with no PH and was an excellent predictor of CSPH. MRE spleen stiffness appears sensitive to hemodynamic changes associated with PH.