CT Appearance of Hepatic Fibrosis
A fibrotic liver on CT demonstrates limited findings in early disease but shows characteristic morphologic changes and parenchymal heterogeneity in advanced stages, though CT has poor sensitivity for detecting fibrosis compared to MR elastography. 1
Key Limitations of CT for Fibrosis Detection
Noncontrast CT has minimal utility for assessing hepatic fibrosis because it only demonstrates gross structural changes that appear in very advanced disease stages. 1 Even when multiple morphologic features are evaluated together, CT sensitivity remains too low to exclude hepatic fibrosis. 1, 2
Contrast-Enhanced CT Findings
Contrast-enhanced CT performs better than noncontrast by revealing:
- Parenchymal heterogeneity with patchy or reticular enhancement patterns throughout the liver 1
- Lattice-like macroscopic bands of fibrosis that enhance during contrast phases 1
- Heterogeneous enhancement with mosaic patterns, particularly visible during late arterial and portal venous phases 1
Morphologic Features in Advanced Fibrosis/Cirrhosis
When fibrosis progresses to cirrhosis, CT may demonstrate these structural changes (though they indicate advanced disease): 1
- Liver surface nodularity, especially of the anterior left lobe
- Right lobe atrophy with caudate lobe and lateral segment hypertrophy
- Right hepatic posterior "notch" sign
- Enlarged caudate-to-right lobe ratio (modified ratio >0.90)
- Narrow hepatic veins (right hepatic vein <5 mm)
- Enlarged hilar periportal space (>10 mm thickness)
- Expanded gallbladder fossa
Important caveat: These morphologic features are subjective and only present in later fibrosis stages, making them unreliable for early detection. 1
Secondary Signs of Portal Hypertension
In advanced cirrhosis, CT may show: 3
- Splenomegaly
- Ascites
- Varices
- Portal vein flow abnormalities
Clinical Implications
CT-based surveillance for hepatocellular carcinoma in cirrhotic patients achieves only 62.5% sensitivity for early-stage HCC, highlighting significant limitations in nodular cirrhotic livers where fibrous septa and regenerative nodules mask small tumors. 2
Superior Alternative Modalities
The American College of Radiology states that MR elastography is currently the most accurate imaging modality for diagnosing and staging hepatic fibrosis, with superior performance compared to CT. 1, 2 When MRI is unavailable or contraindicated, ultrasound elastography (particularly ARFI) should be used instead of relying on CT morphology alone. 2
CT perfusion techniques can assess fibrosis by measuring increased arterial blood supply as fibrosis progresses, but these methods are highly technique-dependent, require substantial postprocessing, and are not clinically standard. 1, 2