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--- leversteatos [2025/10/21 13:44] – skapad akestorck
+++ leversteatos [2025/10/31 07:55] (aktuell) – akestorck
@@ Rad 1: / Rad 1: @@
 ====== Leversteatos ======
+===== Summary =====
+Liver steatosis is characterized by excessive triglyceride accumulation within hepatocytes, either diffusely or focally. It may be alcoholic or nonalcoholic (NAFLD) in origin and can progress to steatohepatitis, fibrosis, or cirrhosis. The condition is often asymptomatic and detected incidentally on imaging. Accurate imaging evaluation allows both detection and quantification of hepatic fat content.
+==== Radiographic Features ====
+Ultrasound (First-line modality):
+Echogenicity: Diffuse increase in hepatic echogenicity (“bright liver”) with posterior beam attenuation.
+Vascular blurring: Poor delineation of portal and hepatic veins.
+Liver–renal contrast: Liver more echogenic than right renal cortex.
+Focal changes: Geographic areas of fatty sparing or deposition, commonly near the gallbladder fossa, porta hepatis, or falciform ligament.
+Grading (Qualitative):
+Mild (Grade I): Slight diffuse echogenicity; normal diaphragm and vessel visualization.
+Moderate (Grade II): Moderate echogenicity with mild vessel and diaphragm blurring.
+Severe (Grade III): Marked echogenicity with poor visualization of posterior structures.
+CT (Quantification on Non-contrast images):
+Attenuation: Decreased hepatic attenuation due to fat (normal ≈ 50–65 HU).
+Quantitative criteria (non-contrast):
+Mild steatosis: 30–39 HU.
+Moderate to severe: <30 HU.
+Liver–spleen attenuation difference: >10 HU (liver lower) diagnostic for steatosis.
+Contrast-enhanced CT:
+Not suitable for fat quantification due to variable enhancement.
+May show areas of relative hypoattenuation (focal steatosis) or hyperattenuation (fatty sparing).
+Useful to exclude mass effect or underlying focal lesions.
+MRI (Most sensitive and specific):
+In-phase/out-of-phase imaging:
+Signal loss on out-of-phase images indicates intracellular fat.
+Fat fraction >5% diagnostic.
+MR Proton Density Fat Fraction (PDFF):
+Quantifies hepatic fat accurately; normal <5.5%.
+Distribution patterns: Diffuse, geographic, or nodular; absence of mass effect and preserved vascular structures favor benignity.
+Elastography (US or MR):
+Evaluates coexisting fibrosis or steatohepatitis in NAFLD patients.