Acoustic radiation force impulse elastography of spleen – a new tool to assess the severity of portal hypertension

Background: The gold standard method considered to assess the severity of portal hypertension is the hepatic venous pressure gradient (HVPG). Patients with severe portal hypertension (HVPG ≥ 12 mm Hg) are at risk for variceal bleeding, with mortality rates ranging from 20% to 35%. However, due to its invasiveness, it is gradually getting replaced by Doppler ultrasound where, Damping index (DI) reflects portal pressure and liver dysfunction. Spleen stiffness measurements by acoustic radiation force impulse (ARFI) elastography have been proposed as a new, non-invasive parameter for assessment of portal hypertension. Objectives: To assess value of spleen stiffness measurements by acoustic radiation force impulse (ARFI) elastography in predicting the severity of portal hypertension. Materials and Methods: 130 clinically diagnosed cases of portal hypertension were included in the study. Spleen Elastography was performed by ARFI method to calculate the median shear wave velocity of the spleen. Results: In our series of 130 cases, the Spleen stiffness (SS) as measured by ARFI shear wave velocity ranged between 2.54 – 4.1 m/s with mean SSM of 3.14 ± 0.28 m/s. In our study, the Spleen stiffness cut-off value of 3.11 m/sec was considered as the better indicator to rule out the presence of severe portal hypertension with a sensitivity of 93.3% and specificity of 80% (p<0.05). Conclusion: Increased value of Spleen stiffness measurement by ARFI elastography has shown a strong association with the severity of portal hypertension.