Arterio-portal shunts in the cirrhotic liver: perfusion computed tomography for distinction of arterialized pseudolesions from hepatocellular carcinoma.

OBJECTIVES: To determine perfusion computed tomography (P-CT) findings for distinction of arterial pseudolesions (APL) from hepatocellular carcinoma (HCC) in the cirrhotic liver.

METHODS: 32 APL and 21 HCC in 20 cirrhotic patients (15 men; 65 ± 10 years), who underwent P-CT for evaluation of HCC pre- (N = 9) or post- (N = 11) transarterial chemoembolization, were retrospectively included using CT follow-up as the standard of reference. All 53 lesions were qualitatively (visual) and quantitatively (perfusion parameters) analysed according to their shape (wedge, irregular, nodular), location (not-/adjunct to a fistula), arterial liver perfusion (ALP), portal venous liver perfusion (PLP), hepatic perfusion index (HPI). Accuracy for diagnosis of HCC was determined using receiver operating characteristics.

RESULTS: 18/32 (56 %) APL were wedge shaped, 10/32 (31 %) irregular and 4/32 (12 %) nodular, while 11/21 (52 %) HCC were nodular or 10/21 (48 %) irregular, but never wedge shaped. Significant difference between APL and HCC was seen for lesion shape in pretreated lesions (P < 0.001), and for PLP and HPI in both pre- and post-treated lesions (all, P < 0.001). Diagnostic accuracy for HCC was best for combined assessment of lesion configuration and PLP showing an area under the curve of 0.901.

CONCLUSION: Combined assessment of lesion configuration and portal venous perfusion derived from P-CT allows best to discriminate APL from HCC with high diagnostic accuracy.

KEY POINTS: • Arterio-portal shunting is common in the cirrhotic liver, especially after local treatment. • Arterial pseudolesions (APL) due to shunting might mimic hepatocellular carcinoma (HCC). • Perfusion-CT allows for qualitative and quantitative assessment of liver lesions. • Lesion configuration fails to discriminate APL from HCC in locally treated patients. • Integration of quantitative perfusion analysis improves accuracy for diagnosis of HCC.