Please interpret the abdominal MRI showing diffuse loss of signal on opposed‑phase images consistent with hepatic steatosis and several small simple hepatic cysts.

MRI Interpretation: Hepatic Steatosis with Simple Hepatic Cysts

This MRI demonstrates diffuse hepatic steatosis (fatty liver) with incidental simple hepatic cysts—both benign findings that require risk stratification for underlying metabolic liver disease but no intervention for the cysts themselves.

Understanding the MRI Findings

Signal Loss on Opposed-Phase Imaging

The diffuse signal dropout on opposed-phase (out-of-phase) images is the hallmark MRI finding of hepatic steatosis. 1 This occurs because:

• In opposed-phase imaging, water and fat signals cancel each other, causing the liver to appear darker when intracellular fat is present 1
• Normal liver maintains similar signal intensity between in-phase and opposed-phase images since there is no fat-water interference 1
• MRI can detect hepatic fat content as low as 5% with 76.7-90% sensitivity and 87.1-91% specificity, making it superior to both ultrasound and CT for mild steatosis 1

The diffuse pattern indicates that fat accumulation affects the entire liver parenchyma rather than focal areas. 2

Small Scattered Hepatic Cysts

Simple hepatic cysts are benign, fluid-filled lesions that arise from aberrant bile duct cells during embryonic development and require no treatment when asymptomatic. 3 These are extremely common incidental findings on cross-sectional imaging. 3

Once definitively characterized as simple cysts on imaging, they do not require routine follow-up. 4 Simple cysts without enhancement exclude malignancy. 4

Clinical Significance and Next Steps

Immediate Risk Stratification for Hepatic Steatosis

Calculate the FIB-4 score immediately using age, AST, ALT, and platelet count to stratify fibrosis risk. 4

• FIB-4 <1.3: Low risk for advanced fibrosis 4
• FIB-4 1.3-2.67: Intermediate risk requiring additional testing 4
• FIB-4 >2.67: High risk requiring hepatology referral 4

Alternatively, calculate the Hepatic Steatosis Index (HSI) = 8 × (ALT/AST) + BMI + 2 (if female) + 2 (if diabetic). 5

• HSI <30: Excludes steatosis with 93.1% sensitivity 5
• HSI >36: Confirms steatosis with 92.4% specificity 5
• HSI 30-36: Gray zone requiring additional evaluation 5

Baseline Laboratory Evaluation

Obtain complete blood count, comprehensive metabolic panel, lipid panel, hemoglobin A1c, and fasting glucose to screen for metabolic syndrome components. 4 This identifies diabetes, dyslipidemia, and other cardiovascular risk factors that commonly coexist with hepatic steatosis. 1

Evaluate for secondary causes of steatosis by assessing alcohol use with validated screening tools. 4 The AST:ALT ratio is typically >2 in alcohol-induced fatty liver disease and <1 in metabolic disease-related fatty liver. 1

Consider testing for chronic hepatitis B and C if not previously done. 4

Primary Treatment: Lifestyle Modification

Prescribe a hypocaloric Mediterranean diet with 500-1000 kcal daily deficit targeting 7-10% weight loss. 4 Weight loss of 3-5% improves steatosis, while 7-10% is needed to improve inflammation and fibrosis. 4

Prescribe 150-300 minutes weekly of moderate-intensity aerobic exercise or 75-150 minutes of vigorous-intensity activity. 4 Physical activity improves hepatic steatosis independent of weight loss. 4

Pharmacologic Considerations

If type 2 diabetes is present, prioritize GLP-1 receptor agonists (semaglutide or liraglutide) or SGLT2 inhibitors, as these agents improve both glycemic control and liver histology. 4

If dyslipidemia is present, initiate or continue statin therapy. 4 Statins are safe and recommended in hepatic steatosis. 4

Follow-Up Strategy

For low-risk patients (FIB-4 <1.3), repeat liver function tests and FIB-4 calculation in 6-12 months, then reassess FIB-4 every 2-3 years if it remains low. 4

For intermediate or high-risk patients, refer to hepatology for consideration of advanced fibrosis testing (elastography or proprietary scores). 4

Critical Pitfalls to Avoid

Do not pursue rapid weight loss; recommend gradual loss of maximum 1 kg/week to prevent worsening of liver disease. 4

Avoid medications that worsen steatosis, including corticosteroids, amiodarone, methotrexate, tamoxifen, estrogens, tetracyclines, and valproic acid. 4

Do not biopsy or further image the simple hepatic cysts unless they develop symptoms, irregular walls, septations, calcifications, or daughter cysts. 3 These features would require enhanced CT or MRI to differentiate simple cysts from cystic neoplasms or hydatid cysts. 3

Do not assume MRI can differentiate simple steatosis from nonalcoholic steatohepatitis (NASH)—imaging cannot distinguish between these entities. 2 This is why fibrosis risk stratification with FIB-4 is essential. 4

Understanding the Disease Spectrum

Hepatic steatosis represents a spectrum of disease. 1 Simple hepatic steatosis occurs in 70-75% of cases without cellular injury, while nonalcoholic steatohepatitis (NASH) occurs in 25-30% with hepatocyte injury and inflammation. 1 Progressive inflammation can result in fibrosis leading to cirrhosis and hepatocellular carcinoma. 1

NAFLD is the most common liver disease in developed countries, with 20-30% prevalence in the general population, increasing to 70% with obesity and 90% with diabetes mellitus. 1