What do CT (Computed Tomography) scans show in primary biliary cirrhosis?

CT Scan Findings in Primary Biliary Cirrhosis

CT scans in primary biliary cirrhosis (PBC) typically show morphological changes of the liver including surface nodularity, right lobe atrophy, caudate lobe hypertrophy, and heterogeneous liver parenchyma, though these findings are often not apparent until advanced stages of the disease. 1

Key CT Findings in PBC

Liver Morphology Changes

• Liver size varies depending on disease stage - enlarged or normal in early disease, small in advanced disease 2
• Heterogeneous liver attenuation, particularly in advanced disease 2
• Segmental hepatic atrophy (particularly right lobe) and hypertrophy (particularly caudate lobe) 1, 2
• Irregular liver surface due to regenerative nodules in advanced disease 2
• Lace-like fibrosis pattern in approximately one-third of cases, even in less advanced disease 2

Portal Hypertension Signs

• Portal and splenic vein enlargement 2
• Venous collaterals/varices (present in 62% of patients even before frank cirrhosis) 2
• Splenomegaly (common in advanced disease) 2
• Ascites (can be seen in 24% of patients even with less advanced disease) 2

Other Common Findings

• Lymphadenopathy (seen in up to 88% of patients) 2
• Periportal halo sign (rounded low signal intensity lesions centering portal vein branches) - better visualized on MRI but may be detected on CT 3
• Enhancement of lattice-like macroscopic bands of fibrosis throughout hepatic parenchyma on contrast-enhanced CT 1

Limitations of CT in PBC

• Noncontrast CT has limited utility in assessing hepatic fibrosis as it relies on gross structural changes typically not present until advanced disease 1
• CT is less sensitive than MRI for detecting early stages of PBC 3
• Morphologic changes on CT are not specific to PBC and can resemble other forms of cirrhosis in advanced stages 2

Contrast-Enhanced vs. Non-Contrast CT

• Contrast-enhanced CT is more useful than non-contrast CT as it can demonstrate:
  • Parenchymal heterogeneity 1
  • Enhancement of fibrotic bands throughout hepatic parenchyma 1
  • Vascular abnormalities related to portal hypertension 1, 2
• CT perfusion techniques have been described for assessing hepatic fibrosis but are highly technique-dependent and not considered standard clinical practice 1

Clinical Relevance

• CT can demonstrate complications like varices and ascites before frank cirrhosis is evident 2
• CT helps evaluate disease progression and complications 2
• CT can detect hepatocellular carcinoma, which occurs in approximately 8% of PBC patients 2
• CT findings should be correlated with clinical and laboratory findings for optimal diagnosis and management 1, 2

Alternative Imaging Modalities

• MR elastography is currently the most accurate imaging modality for diagnosis and staging of hepatic fibrosis in chronic liver diseases including PBC 1
• MRI with MRCP may provide additional value in evaluating PBC, particularly for assessing bile duct abnormalities and subtle parenchymal changes 1, 3
• Ultrasound is typically the first-line imaging modality for evaluating jaundice and suspected liver disease 1