Elastography for the Evaluation of Portal Hypertension

*Roxana Șirli, Iulia Rațiu and Ioan Sporea*

#### **Abstract**

Liver cirrhosis, regardless of its etiology, is an important health problem with a chronic evolution, characterized by the possibility of developing several important complications. The best management of these patients implies the correct and early diagnosis of the disease and of its complications. A major complication of cirrhosis is portal hypertension. The reference method for its diagnosis is the direct measurement of hepatic vein portal gradient, an invasive procedure. In the last years, several noninvasive techniques for the evaluation of liver fibrosis were developed, such as biological tests and elastographic methods. Ultrasound-based and MRI-based elastographic techniques have been assessed as predictive tools for the presence and severity of portal hypertension. This paper reviews published data regarding the value of ultrasound and MRI-based elastography (liver, spleen, or both) for the evaluation of portal hypertension.

**Keywords:** portal hypertension, clinically significant portal hypertension (CSPH), elastography, liver stiffness, spleen stiffness

#### **1. Introduction**

The prevalence of chronic hepatopathies in daily practice is increasing due to their multiple causes, such as chronic viral infections, alcoholic or non-alcoholic steatohepatitis, cholestatic or autoimmune chronic liver disease. Evaluation of such patients is important for therapeutical decisions, follow-up, and for prognosis assessment.

One main complication of advanced chronic liver disease is portal hypertension (PHT), and the exact evaluation of this entity is crucial for further steps. The direct measurement of hepatic vein portal gradient (HVPG) is the "gold standard" for portal hypertension assessment, but this procedure is invasive, and it is not available in all centers of hepatology. Upper endoscopy for the evaluation of possible esophageal varices or portal gastropathy is a surrogate used in daily practice. Ultrasound and other imaging methods that can reveal collateral circulation in the abdomen can be used to suggest portal hypertension.

Elastography techniques developed in the last 10–15 years mainly evaluate liver stiffness as a marker of fibrosis severity and, lately of portal hypertension. More recently, spleen stiffness was used for the assessment of liver disease severity and evaluation of portal hypertension. Ultrasound-based elastography techniques are the most used in practice, but some studies also evaluated magnetic resonance elastography (MR-E).
