Tissue harmonic imaging in the diagnosis of small hepatocellular carcinoma: Usefulness for detecting posterior acoustic enhancement

We attempted to evaluate the usefulness of ultrasonic tissue harmonic imaging (HI) in the diagnosis of small hepatocellular carcinoma (HCC) and compare its effectiveness with that of conventional fundamental imaging (FI) prospectively. Nine patients with 16 nodules of HCC measuring less than 20 mm in diameter were evaluated with both FI and HI. The boundaries of 14 nodules were more clearly visualized on HI than on FI. Posterior acoustic enhancement, which is diagnostic of HCC, was not detected on FI, although it was detected in 5 nodules on HI (p<0.05); however, one nodule located in a section of the liver that was 8 cm below the abdominal wall was visualized only by FI. We conclude that HI is more useful than FI in the diagnosis of small HCC nodules, although HI has minor limitations of the applicable location.