Transient Hepatic Parenchymal Enhancement detected at dynamic imaging: A short instruction manual for the clinician

Basic knowledge in the interpretation of hepatic imaging is essential for the clinical hepatologist. In recent years, the availability of dynamic imaging studies of the liver using computed tomography or magnetic resonance has led to appreciate the importance of early changes in arterial perfusion for the interpretation of hepatic lesions. Transient Hepatic Parenchymal Enhancement (THPE) is defined as a normal area of liver parenchyma that enhances after injection of contrast agent during the arterial phase of perfusion. Appearance of this sign is mostly associated with a reduction in portal perfusion or with inflammation, and appears in different morphologic patterns. THPE should not be considered a radiological artefact, and its interpretation is essential to avoid misclassification of hepatic lesions that may have clinical significance, such as hepatocellular carcinoma or hepatic metastases. In this short review we provide essential information on the causes, pathophysiology and morphology of THPE, and discuss the relevance of these findings in a clinical perspective.