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Chulalongkorn Medical Journal

Abstract

Background : Most hepatocellular carcinomas (HCCs) occur in an underlyingcirrhotic liver. Some of which are difficult to diagnose becausethey do not show typical enhancement pattern, and cirrhoticnodules can mimic an HCC. Although multiphasic dynamiccomputed tomography (CT) has been used for detecting HCC,the usefulness of delayed phase scan is unclear.Objectives : To analyze CT appearances of HCCs and other associatedfindings in cirrhotic livers, and to determine the usefulness ofdelayed phase scan for detecting HCCs.Setting : Department of Radiology, Faculty of Medicine, ChulalongkornUniversityResearch design : Retrospective studyMaterials and Methods : Fifty-three cirrhotic patients with 109 hepatic lesions underwentmultiphasic dynamic CT scan. They were considered to haveHCCs according to the Barcelona EASL 2000 HCC guidelineand AASLD criteria. The combination of unenhanced, arterialand portal venous phase scans and the combination ofunenhanced, arterial, portal venous and delayed phase scans ofeach patient was reviewed separately by two independentradiologists. Each lesion was evaluated regarding its size,focalization, location, attenuation, enhancement pattern andconfidence level for diagnosing HCC.Results : Most HCCs showed wash out of contrast material on portalvenous phase scan (64.2 -66%). Approximately, one-fourth ofHCCs showed wash out on delayed phase scan, higherpercentage in small HCCs with a diameter of less than 2 cm(31.6 - 42.1%) compared to those with a diameter of more than2 cm (23.4 - 24.5%). On delayed phase scan, 40.4% of HCCsshowed capsular enhancement. There were tumor involvementof portal veins and hepatic veins in 17 patients (32.1%) and onepatient (1.9%), respectively. Arterioportal shunt was present in5 patients (9.4%) and bile duct dilatation was found in 3 patients(5.7%). Mean confidence level for diagnosing HCC by combinedunenhanced, arterial and portal venous phase scans was4.28-4.45 and 4.63 for combined unenhanced, arterial, portalvenous and delayed phase scans. The confidence levelincreased significantly after adding the delayed phase scan(P<.05).Conclusion : CT findings on delayed phase scan are helpful in the diagnosisof HCC, especially in small HCCs with a diameter of less than2 cm. Adding the delayed phase scan shows significantlyincreased confidence level and can confirm the diagnosis.

Publisher

Faculty of Medicine, Chulalongkorn University

First Page

347

Last Page

361

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