Masahiko Yamada

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AIM To determine whether the findings of microflow imaging (MFI), composed of a flash replenishment and a maximum intensity holding sequence, using contrast-enhanced sonography, correlate with the degree of histological differentiation of hepatocellular carcinoma (HCC). METHODS This study was approved by the institutional review board; patients gave(More)
Of the 692 patients with hepatocellular carcinoma (HCC) who were admitted to our hospital between 1976 and 1990, 60 (8.8%) had small HCC with a maximal diameter of below 2 cm. The outcome of these 60 cases was analyzed after they had been divided into 4 groups based on the therapeutic method used: operation group (17 cases), percutaneous ethanol injection(More)
We report two cirrhotic patients with gastric antral vascular ectasia (GAVE) in whom chronic blood loss presented a major problem. Case 1, a 69-year-old man, had alcoholic liver cirrhosis, and case 2, a 75-year-old woman, had liver cirrhosis associated with hepatitis C virus. The patients required repeated blood transfusions but still exhibited persistent(More)
AIM To verify whether arterial-phase contrast-enhanced ultrasonography (CEUS) of tumor parenchymal tissue is useful for evaluation of anti-angiogenesis agents. METHODS Rabbits with liver tumor were subjected to CEUS, and images of the nodular maximal diameter in vascular phase were recorded. Image analysis was performed to plot the time intensity curve(More)
OBJECTIVE The purpose of this study is to compare the accuracy of ultrasound-guided puncture using new real-time 3D (4D) ultrasound and conventional 2D ultrasound for focal hepatic masses using a liver phantom. MATERIALS AND METHODS A 4D ultrasound system equipped with a 5-MHz 4D probe displayed both axial and orthogonal images parallel to a puncture line(More)
Heat shock proteins (HSPs) induced by thermal ablation therapy may help presenting tumor antigen to the host immune system and be a valuable adjuvant in the ablation therapy of liver cancer. This paper described our preliminary study on the expression of HSP70 in rabbit liver after contrast-enhanced ultrasound (CEUS) and radiofrequency (RF) ablation.(More)
Flash-replenishment (FR) utilizes destruction of microbubbles in the scan volume by high-power ultrasound and enables to observe reperfusion at a low acoustic power. In this paper, we introduced theoretic equation between probability density function (PDF) of the transit time in the scan volume and time intensity curve (TIC) measured by FR method. From the(More)
Computed tomography (CT), performed in a healthy 28-year-old man after minor head injury, detected a frontal base tumor. Neurological examination revealed left hyposmia. On magnetic resonance imaging scans, there was a heterogeneously enhanced tumor located in the left paramedian frontal base with extension into the left ethmoid sinus. Angiography showed a(More)
PURPOSE To investigate the behavior of perflubutane microbubbles outside and inside Kupffer cells during diagnostic ultrasound (US) examination, and to determine the thresholds of the acoustic pressure of different kinds of behavior. METHODS Acoustic behavior of perflubutane microbubbles inside and outside Kupffer cells in an acoustic field induced by a(More)
AIM To compare the difference between tumor-induced lymph node enlargement and inflammation-induced lymph node enlargement by contrast-enhanced ultrasonography and pathological findings. METHODS A model of tumor-induced lymph node metastasis was prepared by embedding a VX2 tumor into the hind paws of white rabbits. A model of inflammation-induced(More)