Fatty Liver Disease: Pathophysiology and Imaging Features

Abstract

Fatty liver is a benign condition to start with and is characterized by excess triglyceride in the hepatocytes. However, in the long term, it can lead to increased oxidative stress & inflammation, with resultant steatohepatitis. This can subsequently progress to cirrhosis and eventually an increased risk of developing hepatocellular carcinoma (HCC). Liver biopsy is the gold standard for quantification of fat and assessing the degree of fibrosis, however, it is invasive and cannot be applied to a wider patient population. Conventional modalities like ultrasound offer a qualitative assessment of fat and are more subjective. Non-enhanced CT scan has been effectively used for fat quantification based on Hounsfield values. MRI & more recently MRI PDFF (proton density fat fraction) offers accurate diagnosis, quantification, and monitoring of fatty liver disease in a noninvasive manner. This acts like an Imaging biomarker. Newer techniques like USG Elastography & MR Elastography help in the detection of fibrosis. Steatohepatitis and early liver fibrosis are reversible and it is crucial to detect and quantify to guide disease management. The radiologist can play a vital role in quantifying fat, detecting fibrosis, and early signs of chronic liver disease.

Practical Steps of Shear Wave Elastography for Nonalcoholic Fatty Liver Disease in an Adult Population

“…These include several imaging modalities like ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). 9 CT performs adequately in assessing significant fibrosis and cirrhosis and MRI studies exhibits great accuracy at all stages of chronic liver diseases but is costly.…”