Liver Imaging

Liver lesions have a broad spectrum of pathologies, ranging from benign lesions such as hemangiomas to malignant lesions such as primary hepatocellular carcinoma and metastasis. Imaging is a crucial step in diagnosing these conditions, as liver enzymes can be elevated in up to 9% of individuals in the USA. A combination of medical history, serologic, and radiologic investigations can provide a diagnosis in most cases. Liver lesions can be categorized into focal and diffuse liver lesions. 1. Benign lesions that do not need treatment if they are asymptomatic, including hepatic hemangiomas, focal nodular hyperplasias, and benign liver cysts. 2. Benign lesions that require treatment, including hepatic adenoma, hepatic abscess, and hepatic adenomas. 3. Malignant lesions, including hepatocellular carcinoma, cholangiocarcinoma, hepatic angiosarcoma, and liver metastases. 1. Cholangiocellar: hepatic cyst, biliary cystadenoma, intraductal papillary neoplasm of the bile ducts, peribiliary cyst, intrahepatic bile adenoma (see Hepatic Biloma). 2. Hepatocellular: focal nodular hyperplasia, hepatic adenoma. 3. Mesenchymal: hemangioma, lipoma. Liver ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) are the primary imaging modalities to diagnose liver lesions. Postcontrast imaging can help distinguish lesions depending on their degree of vascularity and composition. Postcontrast hepatic imaging falls into 3 distinct phases: the arterial phase, the portal venous phase, and the delayed venous phase. Ultrasound can be a method of choice as a screening modality, and contrast-enhanced multidetector CT (MDCT) is a modality of choice in most hepatic imaging. MRI plays a role in better-characterizing lesions with equivocal features on US and CT.