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--- leversteatos [2025/10/21 13:44] – skapad akestorck
+++ leversteatos [2026/01/13 09:28] (aktuell) – akestorck
@@ Rad 1: / Rad 1: @@
-====== Leversteatos ======
+====== Liver steatosis ======
+**Hepatic steatosis**, also known as **fatty liver disease**, refers to abnormal accumulation of fat within hepatocytes, most commonly manifesting as **non-alcoholic fatty liver disease (NAFLD)**.
+===== Epidemiology =====
+Hepatic steatosis affects up to 30% of the general population in Western countries, with rising prevalence linked to obesity, diabetes, and metabolic syndrome. Prevalence exceeds 70% in patients with type 2 diabetes and reaches 90% in those undergoing bariatric surgery.
+===== Clinical presentation =====
+Most cases remain asymptomatic and are detected incidentally on ultrasound or other imaging. Symptomatic patients may report right upper quadrant discomfort, fatigue, or elevated liver enzymes.
+===== Pathology =====
+Steatosis results from impaired fat metabolism, with triglycerides accumulating in >5% of hepatocytes. Macrovesicular steatosis predominates, featuring a single large cytoplasmic fat droplet displacing the nucleus.
+===== Radiographic features =====
+==== Ultrasonography ====
+  * **Hyperechoic liver parenchyma** ("bright liver") compared to kidney or spleen
+  * **Grading**:
+^ Grade     ^ Features                                      ^
+| Mild      | Slight echogenicity increase                   |
+| Moderate  | Impaired vessel wall visualization             |
+| Severe    | Poor diaphragm/portal vein visibility          |
+==== Computed tomography ====
+  * **Unenhanced CT**: Liver attenuation <40 HU absolute or >10 HU lower than spleen
+  * **Contrast-enhanced**: Focal sparing appears hyperdense relative to steatotic parenchyma (gallbladder fossa, segment IV)
+  * Dual-energy CT improves quantification
+==== Magnetic resonance imaging ====
+  * **Chemical shift imaging** (in/out-of-phase): Signal dropout on opposed-phase images (>5% fat)
+  * **Proton density fat fraction (PDFF)**: Gold standard for quantification
+  * **Spectroscopy**: Measures fat fraction directly
+===== Treatment and prognosis =====
+Management targets underlying causes (weight loss, diabetes control). Steatosis alone carries excellent prognosis without fibrosis; NASH risks progression to cirrhosis (20-30%).
+===== Differential diagnosis =====
+  * Glycogen storage disease (US: hyperechoic but vessels clear)
+  * Acute hepatitis (diffuse hypoechoic)
+  * Focal fat sparing/deposition mimics mass
+  * Iron overload (high attenuation on CT)
+===== References =====
+* [[https://pubs.rsna.org/doi/full/10.1148/rg.266065004|RadioGraphics 2006: Fatty Liver]]
+* [[https://pmc.ncbi.nlm.nih.gov/articles/PMC6824276/|Ultrasound Med 2019]]
+* [[https://ajronline.org/doi/10.2214/AJR.11.7838|AJR Am J Roentgenol 2012]]
+* [[https://pubs.rsna.org/doi/full/10.1148/radiol.2021204288|Radiology 2021]]
+* [[https://pmc.ncbi.nlm.nih.gov/articles/PMC4064084/|World J Gastroenterol 2014]]
+* [[https://www.sciencedirect.com/science/article/abs/pii/S0720048X06004451|Eur J Radiol 2007]]
+> **Medical Disclaimer**: Portions of this content were AI-generated to facilitate rapid knowledge synthesis. Radiologists and clinicians must independently verify all information against peer-reviewed literature, institutional protocols, and patient-specific factors before clinical application.