Objective: The purpose of this study is to determine the added diagnostic value of the delayed venous
phase in diagnosing hepatocellular carcinoma (HCC) using a multidetector helical CT scanning in
conjunction with hepatic arterial and portal venous phases.
Patients and Methods: Thirty six patients with suspected HCC after ultrasonographic examination
underwent MDCT imaging. A total number of 62 biopsy-approved HCC lesions were included in this
study, 58 lesions were sonographically detected, and extra four lesions were detected only after triphasic
MDCT scanning. Images were interpreted regarding the size, homogeneity, pattern of enhancement,
hypervascularity and washout, capsule, abnormal internal vessels, calcifications, fat and central scar.
Results: Most of the HCCs were hypervascular (91.2%) exhibiting mosaic pattern of enhancement
on the hepatic arterial and portal venous phases (82.5%, and 78.9% respectively). Portal venous phase
washout accounted for 76.9% of hypervascular HCCs. Capsulated lesions accounted for 27.1%; 37.5%
of these capsules were identified on the delayed phase only. The dual-phase MDCT detected 57 (91.9%)
out of the 62 lesions compared with the triple–phase MDCT where 59 (95.2%) lesions were detected. Two
hepatocellular carcinomas (3.4%) were seen only in the delayed phase as hypoattenuating nodules.
Conclusion: Delayed venous phase of hepatic CT is beneficial in detection and characterization of
hepatocellular carcinoma, as it detected small, hypoattenuating, and capsulated hepatocellular carcinomas
in a higher rate than biphasic imaging alone. Our results encourage the use of a triple-phase helical CT
technique for the evaluation of patients with hypovascular hepatic HCCs. This technique is recommended to
be performed especially in patients who are candidates for curative partial hepatic resection or interventional
management.