Question

Evaluation of fatty liver.

Hint:

Ultrasound is the most commonly used first-line imaging tool for diagnosing fatty liver. MRI with PDFF offers the most accurate assessment of liver fat content.

Answer 1

Step 1: Understanding Fatty Liver.
Fatty liver, or hepatic steatosis, is a condition characterized by excessive fat accumulation within the liver cells. It is commonly seen in conditions such as obesity, diabetes, and chronic alcohol consumption. Imaging plays a crucial role in diagnosing fatty liver and assessing its severity.

Step 2: Imaging Techniques for Fatty Liver Evaluation.

1. Ultrasound (US):
- First-line imaging: Ultrasound is the most commonly used initial imaging modality to evaluate fatty liver. It is non-invasive and readily available.
- Findings: Fatty liver typically appears as a hyperechoic (brighter) liver compared to the kidney. There may be a loss of the normal distinction between the liver and the right kidney due to the increased fat content.
- Limitations: Ultrasound may not be able to detect early or mild fatty liver and is less accurate in obese patients due to difficulty in penetration.

2. CT Scan (Computed Tomography):
- Fatty Liver Sign: On a CT scan, the liver appears less dense than normal due to fat accumulation. It is often seen as a lower attenuation of the liver parenchyma compared to the spleen.
- Limitations: While CT can detect fatty liver, it is not as sensitive as ultrasound or MRI and involves radiation exposure.

3. MRI (Magnetic Resonance Imaging):
- MRI Proton Density Fat Fraction (PDFF): MRI, particularly with the use of PDFF, is the most sensitive method for quantifying liver fat content. MRI provides a non-invasive way to assess the degree of steatosis.
- Findings: Fatty liver shows hyperintensity (bright areas) on MRI, especially in T1 and T2-weighted images. PDFF mapping allows for quantitative assessment of liver fat content, providing accurate evaluation of the severity of steatosis.

4. Liver Biopsy (for confirmation):
- While imaging can diagnose fatty liver, a liver biopsy may be required to assess the degree of steatosis and to exclude other liver diseases, such as cirrhosis or liver fibrosis.

Step 3: Conclusion.
Ultrasound is the first-line imaging modality for evaluating fatty liver, while MRI provides the most detailed and accurate assessment. CT can be used, but it is less sensitive and involves radiation. Early diagnosis and appropriate follow-up are essential for managing fatty liver disease.