Keiji Tohara

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.

Ultrasonographic diagnosis of hepatocellular carcinoma

The liver is the largest soft tissue organ in the body and, acoustically, it consists of roughly homogeneous parenchyma. Its position in the body allows negligible interference caused by gas in the digestive canal. Therefore, the liver is an excellent organ to evaluate by means of ultrasonography, especially for the detection of hepatocellular carcinoma (HCC). Normal hepatic parenchyma is seen as a homogeneous and fine echogenic pattern, and focal disorders in the liver cause focal alteration in acoustic impedance which are easily recognizable as abnormally and irregularly localized hypoechoic, isoechoic, hperechoic, or anechoic areas either alone or in combination.

Usefulness of power Doppler imaging in the diagnosis of small focal nodular hyperplasia of the liver

Abstract We evaluated the usefulness of power Doppler imaging (PDI) compared with conventional Doppler imaging (CDI) for the diagnosis of small focal nodular hyperplasia of the liver (FNH) prospectively. Four patients with five FNH lesions, which had been detected incidentally, were diagnosed histologically. All the lesions were less than 3 cm in diameter. In all four patients, the results of blood tests showed normal liver function, HBs antigen and Anti-HCV were negative, and AFP and PIVKA-II were normal. To visualize blood flow, CDI was applied to all these lesions, whilst PDI was additionally applied to four of the lesions. Using CDI, a stellate signal of arterial flow was visualized in only one lesion, while a linear signal of arterial flow was seen in the other four lesions. However, using PDI, a stellate signal of arterial flow was demonstrated in all of the four lesions. In conclusion, PDI was useful in the diagnosis of small FNH. The specific finding for FNH when using PDI was a stellate signal of arterial flow which probably corresponds with the characteristic vasculature present in FNH. Furthermore, it can be proposed that when PDI shows a stellate signal of arterial flow in the nodule found incidentally in a patient with a normal liver, a diagnosis of FNH can be made without requiring invasive procedures, such as angiography or percutaneous target biopsy.