Fatty liver has various imaging patterns that can mimic other conditions, but careful assessment of features such as fat content, location, morphology, enhancement and mass effect can distinguish fatty liver from other lesions. The most common pattern is diffuse homogeneous fat deposition, but other patterns include focal deposits, diffuse with focal sparing, and perivascular or subcapsular deposits. Chemical shift MRI is the most reliable method to assess fat content when findings are equivocal. Recognizing fatty liver patterns can avoid unnecessary procedures by differentiating it from neoplasms, inflammation or vascular abnormalities.

1. Fatty Liver: Imaging Patterns and Pitfalls DR MAHIPAL REDDY INDUR CT SCAN &MRI

2. Introduction The image-based diagnosis of fatty liver usually is straightforward, but fat accumulation may be manifested with unusual structural patterns that mimic neoplastic, inflammatory, or vascular conditions. Leading to : Unnecessary diagnosis test and Invasive procedure

4. Risk Factors and Pathophysiologic Features Histologically Fatty liver: Triglyceride accumulation within the cytoplasm of hepatocytes. Term “fatty infiltration of the liver” is misleading because fat deposition is characterized by accumulation of discrete triglyceride doplets in hepatocytes and rarely, in other cell types. The term fatty liver is more accurate.

5. Conditions Associated with Fatty Liver

12. Normal Liver Fatty Liver To avoid false-positive interpretations, fatty liver should not be considered present if only one or two of these criteria are fulfilled

14. Normal Liver

15. Fatty Liver

20. Chemical shift gradient-echo(GRE) imaging opposed-phase in-phase

24. Diffuse Deposition

25. Diffuse Deposition

26. Diffuse Deposition

39. Perivascular Deposition

40. Perivascular Deposition Periportal fat accumulation in a patient with a chronic hepatitis B infection. Axial unenhanced and late portal venous phase

45. Periportal fat accumulation in a patient with a chronic hepatitis B infection. Axial unenhanced and late portal venous phase Axial opposed-phase Axial in-phase Differentiation of adenoma from fatty deposition in the liver in a woman with a long history of oral contraceptive use. T1-weighted GRE images obtained before and during the hepatic arterial phase

46. P ortal venous phase Axial unenhanced CT Differentiation of hepatocellular carcinoma from fatty deposition in the liver.

47. Differentiation of metastases from fatty liver deposition in a woman undergoing chemotherapy for breast cancer.

50. the upper mediastinum The level of the liver Differentiation of superior vena cava syndrome from fatty liver deposition.

51. Differentiation of hepatic venous congestion from fatty liver deposition.

52. CT images obtained at the same level in the liver. Iatrogenic postbiopsy arteriovenous fistula

54. Differentiation of periportal inflammation from fatty liver deposition. Axial contrast-enhanced CT images obtained during the portal venous phase and the equilibrium phase.

57. Differentiation of a fat-containing tumor from fat deposition in the liver.

60. The end. The end….