Imaging of spontaneous portosystemic shunts in portal hypertension: clinical significance and structured reporting

Portal hypertension leads to the development of a complex and heterogeneous network of portosystemic collateral pathways, which represent adaptive responses to increased portal pressure. Although traditionally considered compensatory mechanisms, growing evidence indicates that Spontaneous Portosystemic Shunts (SPSS) are ineffective in normalizing portal pressure and may contribute to adverse clinical outcomes. In patients with cirrhosis, particularly those with preserved liver function, the presence and extent of SPSS are independently associated with hepatic encephalopathy, variceal bleeding, portal vein thrombosis, and reduced transplant-free survival, highlighting their prognostic relevance. Cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) plays a central role in the noninvasive assessment of portal hypertension by enabling comprehensive mapping of collateral circulation, including shunt size, anatomical course, and drainage pathways. These imaging characteristics are key determinants of clinical impact and therapeutic planning. This pictorial review illustrates the major portosystemic collateral pathways encountered in portal hypertension using representative clinical cases, emphasizing key imaging features and common diagnostic pitfalls, as well as highlighting the clinical significance in each context. Accurate recognition and standardized reporting of SPSS are essential to optimize risk stratification, guide management decisions, and improve outcomes in patients with portal hypertension.