Usefulness of High-Resolution Sonography for Assessement of Hepatocellular Carcinoma in the Transgenic Mice Expressing Hepatitis B Virus X-protein: A Preliminary Study

PURPOSE: To determine the value of high resolution ultrasonography (US) for the detection of hepatocellular carcinoma in the HBx transgenic mice. MATERIALS AND METHODS: Forty-two HBx transgenic mice aged 8-20 (mean, 14) months underwent high-resolution ultrasound using a 10 -12 MHz linear transducer. US findings indicating the presence or absence, number, size and echogenicity of each hepatic tumor were analyzed, and inaddition, color or power Doppler US was used to analyse tumoral vascularity. In each animal, sacrificed less than five hours after US examination, sonographic and pathologic findings were correlated. RESULT: On gross pathologic examination, 20 hepatocellular carcinomas measuring 1.5 -15 (mean, 4.7) mm in diameter were found in 16 mice; US revealed that 17 of the tumors were homogeneous hypoechoic nodules. With regard to tumor detection, sensitivity was 85%, specificity 96%, positive predictive value 0.944, negative predictive value 0.897, and overall accuracy 90%. Doppler US revealed that in three nodules, intratumoral vessels were present. Inthe other 26 mice, gross examination showed that no mass was present; microscopically, however, four nodules measuring 0.3 -1.2 mm were found in four of these animals. Tumoral vascularity detected by color Doppler US corresponded to the intratumoral vessel within the nodules. One peritoneal nodule, confirmed as a metastatic tumor, was found at the greater omentum. CONCLUSION: In HBx transgenic mice, high-resolution US is valuable for the detection of hepatocellular carcinoma.

A Study of Doppler Waveform Using Pulsatile Flow Model

PURPOSE: Through the construction of a pulsatile flow model using an artificial heart pump and stenosis to demonstrate triphasic Doppler waveform, which simulates in vivo conditions, and to evaluate the relationship between Doppler waveform and vascular compliance. MATERIALS AND METHODS: The flow model was constructed using a flowmeter, rubber tube, glass tube with stenosis, and artificial heart pump. Doppler study was carried out at the prestenotic, poststenotic, and distal segments; compliance was changed by changing the length of the rubber tube. RESULTS: With increasing proximal compliance, Doppler waveforms show decreasing peak velocity of the first phase and slightly delayed acceleration time, but the waveform itself did not change significantly. Distal compliance influenced the second phase, and was important for the formation of pulsus tardus and parvus, which without poststenotic vascular compliance, did not develop. The peak velocity of the first phase was inversely proportional to proximal compliance, and those of the second and third phases were directly proportional to distal compliance. CONCLUSION: After constructing this pulsatile flow model, we were able to explain the relationship between vascular compliance and Doppler waveform, and also better understand the formation of pulsus tardus and parvus.