Fat Quantification in the Abdomen.

Area of Science:

• Hepatology
• Radiology
• Medical Imaging

Background:

• Fatty liver disease, characterized by hepatic steatosis, is a growing cause of chronic liver disease and cirrhosis.
• Accurate assessment of hepatic steatosis is crucial for diagnosis and prognosis, as early detection allows for potential reversal.
• Liver biopsy, the current gold standard, has limitations including invasiveness and sampling errors, necessitating noninvasive methods.

Purpose of the Study:

• To review the advancements in noninvasive imaging techniques for assessing hepatic steatosis.
• To highlight the development of advanced magnetic resonance imaging (MRI) methods for accurate fat quantification.
• To discuss the application of these MRI techniques in the liver and other abdominal organs.

Main Methods:

• Review of existing literature on imaging modalities for hepatic steatosis assessment.
• Focus on chemical shift-encoded MRI techniques, including historical methods and recent advancements.
• Discussion of the measurement of proton density fat fraction (PDFF) as a standardized biomarker.

Main Results:

• Ultrasound and CT can suggest hepatic steatosis but cannot accurately quantify fat content.
• Traditional MRI methods (in-phase/out-of-phase) for signal fat fraction are limited by confounders affecting accuracy and reproducibility.
• Advanced MRI techniques enable accurate and reproducible measurement of proton density fat fraction (PDFF).

Conclusions:

• Advanced MRI offers a superior, noninvasive method for quantifying liver fat content compared to traditional techniques.
• Proton density fat fraction (PDFF) measured by advanced MRI is a standardized, accurate, and reproducible biomarker for hepatic steatosis.
• These advanced MRI techniques have potential applications beyond the liver, including the pancreas, adrenal glands, and adipose tissue.