From the Guidelines
The starry sky appearance in liver radiology is a significant finding that is typically associated with biliary hamartomas, which are benign lesions characterized by multiple small, hypoattenuating lesions on CT and hypointense on T1-weighted MRI sequences, with markedly high intensity on T2-weighted sequences 1.
Key Characteristics
- The starry sky appearance is due to the presence of numerous small, round or irregularly shaped lesions scattered throughout the hepatic parenchyma, without communication with the bile ducts 1.
- On MRI, biliary hamartomas are hypointense on T1-weighted sequences and show markedly high intensity on T2-weighted sequences, with well-defined margins and an irregular shape 1.
- The lesions are typically small, ranging in size from 2 to 10 mm, and are predominantly located in the subcapsular and periportal areas 1.
Diagnostic Considerations
- The starry sky appearance can be confirmed using MR cholangiography, which has a high diagnostic sensitivity for detecting biliary hamartomas and ruling out communication with the biliary tree 1.
- Contrast-enhanced MR sequences may show different patterns of enhancement, including no enhancement, a thin and regular rim of enhancement, or a small enhancing mural nodule 1.
From the Research
Significance of Starry Sky Appearance in Liver Radiology
The starry sky appearance in liver radiology is a significant finding that can be associated with various liver conditions. Some of the key points related to this appearance are:
- The starry sky liver is characterized by clearly identified portal venules due to diminished parenchymal echogenicity 2.
- This appearance can be seen in diffuse liver disease, including conditions such as twin-to-twin transfusion syndrome (TTTS) 2, acute viral hepatitis 3, and biliary microhamartomas of the liver 4.
- The starry sky pattern can also be observed in horses with fibrosing hepatic granulomas, although it is likely incidental in most cases and not clinically significant 5.
- In humans, the starry sky appearance of the liver can be associated with hepatomegaly, ascites, and gallbladder wall thickening 3.
- Magnetic resonance cholangiopancreatography (MRCP) and computed tomography (CT) can be used to visualize the starry sky appearance of the liver, which can aid in the diagnosis of underlying liver conditions 4, 6.
- A multiparametric predictive modelling algorithm can be used to analyze CT and MRI images and distinguish between different liver parenchymal conditions, including liver steatosis, steatohepatitis, and cirrhosis 6.
Imaging Modalities
Different imaging modalities can be used to visualize the starry sky appearance of the liver, including:
- Ultrasound: can be used to identify the starry sky pattern in fetal liver sonograms 2 and in horses with fibrosing hepatic granulomas 5.
- Computed Tomography (CT): can be used to visualize the starry sky appearance of the liver and aid in the diagnosis of underlying liver conditions 6.
- Magnetic Resonance Imaging (MRI): can be used to visualize the starry sky appearance of the liver and aid in the diagnosis of underlying liver conditions, including biliary microhamartomas of the liver 4 and liver steatosis, steatohepatitis, and cirrhosis 6.
- Magnetic Resonance Cholangiopancreatography (MRCP): can be used to visualize the starry sky appearance of the liver and aid in the diagnosis of underlying liver conditions, including biliary microhamartomas of the liver 4.