State of the Art in Magnetic Resonance Imaging of Hepatocellular Carcinoma
Liver cancer is the sixth most common cancer worldwide and the second leading cause of cancer mortality. Chronic liver disease caused by viral infection, alcohol abuse, or other factors can lead to cirrhosis. Cirrhosis is the most important clinical risk factor for hepatocellular carcinoma (HCC) whereby the normal hepatic architecture is replaced by fibrous septa and a spectrum of nodules ranging from benign regenerative nodules to HCC, each one of them with different imaging features.
Multiple studies have demonstrated that magnetic resonance imaging (MRI) has excellent sensitivity and specificity for the detection and characterization of HCC in comparison with computed tomography (CT) and ultrasound. Beyond the standard protocol, the use of hepatobiliary contrast agents and the acquisition of additional sequences such as diffusion weighted imaging (DWI) with apparent diffusion coefficient mapping, subtraction imaging, multi-planar acquisition, and hepatobiliary phase, have been proposed to improve the detection of HCC, especially in the case of small, well-differentiated, and post-treatment HCC.
Furthermore, advanced techniques including the quantification of hepatic and intralesional fat and iron, magnetic resonance elastography, radiomics, radiogenomics, and positron emission tomography (PET)-MRI are highly promising for the extraction of new imaging biomarkers that reflect the tumor microenvironment and, in the future, may add decision-making value in the management of patients with HCC. This review summarizes well established and new techniques in MRI evaluation of HCC and highlights the main imaging findings and differential diagnosis of these techniques.