Background: This study aimed to investigate the diagnostic value of contrast-enhanced ultrasound (CEUS) of small hepatocellular carcinomas (HCC) (</=3cm) in patient with cirrhosis.
Materials and methods: Fifty-seven cases with 64 small HCC tumors (</=3cm) were analyzed in this study. In these cases, all patients had liver cirrhosis and surgical or biopsy histopathological diagnosis. Diagnosis of baseline ultrasound (US) and CEUS of each lesion was made separately using a 5-point scoring system based on the US and CEUS characteristics of the lesions and was compared with histopathological results.
Results: All of the 47 moderately to poorly differentiated (MD-PD) HCC presented the "fast-in and fast-out" (FIFO) pattern with fast enhancement within 25s and then a quick wash-out within 90s after contrast injection. Ten of 17 well-differentiated (WD) HCC (58.8%) had "fast-in and slow-out" (FISO) pattern which washed out after 90s and 1 WD HCC had "fast-in and no-out" (FINO) pattern which did not wash out till 360s. Three well differentiated clear cell carcinomas smaller than 1.5cm showed "slow-in and slow-out" (SISO) pattern which enhanced after 25s and washed out after 90s. On baseline US, only 36 lesions (56.3%) were diagnosed as definitely or possibly malignant lesions. After CEUS, 50 lesions (78.1%) with "FIFO" pattern were diagnosed as definitely malignant, while 15.6% (10 lesions) with "FISO" pattern as possibly malignant, only 4 lesions (6.3%) with "FINO" or "SISO" pattern could not be diagnosed by CEUS.
Conclusion: The typical enhancement patterns of "FIFO" or "FISO" of small HCC could improve the diagnostic ability of ultrasound in cirrhotic liver. Small HCC also had atypical enhancement patterns including "FINO" and "SISO". It shows that CEUS could be a useful imaging modality in small HCC diagnosis.