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Biomedical subjects

F Moriyasu

Publications and source records attributed to F Moriyasu.

At least 37 records · Page 2Linked to original sources
PubMed1997

Change in hepatic arterial hemodynamics induced by hepatocellular carcinoma detected with Doppler sonography.

PURPOSE: To understand the hemodynamic differences between the hepatic arterial branches that supply hepatocellular carcinomas (HCCs) and those that do not, we compared the velocity waveforms of both types of arteries. METHODS: Using duplex color Doppler sonography, we examined 38 patients with HCC localized within a single lobe of the liver and 34 patients with chronic liver disease but without HCC (controls). We measured angle-corrected peak systolic velocity and the pulsatility index (PI) of color-coded hepatic arteries along the right anterior segmental portal branch and the vertical segment of the left portal vein. RESULTS: There was no significant difference in peak systolic velocity and PI between the arterial branches tested in the controls. In contrast, we found a significantly lower PI and a higher peak systolic velocity in the arterial branches supplying the tumor than in those not supplying the tumor in patients with an HCC 3 cm or larger in diameter (p < 0.05). The degree of these hemodynamic changes correlated with the tumor size and the presence or absence of tumor thrombus in the major portal branches. CONCLUSIONS: These results indicate that the hepatic arterial branch supplying an HCC has a lower impedance than the branch not supplying the tumor.

Adult↗
PubMed1997

Gray scale second harmonic imaging of the liver: a preliminary animal study.

Gray scale second harmonic imaging (2.5 MHz/5.0 MHz) was evaluated in preliminary animal studies with a new ultrasound contrast agent (FS069). FS069 was administered intravenously in 10 rabbits (6 with normal liver, and 4 with implanted VX-2 tumors) and two woodchucks with hepatocellular carcinomas. The vasculature (including tumor vessels) and liver parenchyma were clearly enhanced at a low dosage (optimal dose was from 0.1 to 0.2 mL/kg) in all cases. Enhancement was reproducible and generally dose-dependent. Tumors were enhanced well during the early phase and tumor enhancement disappeared earlier than that of surrounding normal liver. Arterial phase and portal phase were easily distinguished and patterns of enhancement were diagnostic of the tumors. Gray scale second harmonic imaging is useful in the detection of hepatic tumors and in diagnosis of their hemodynamics.

Albumins↗
PubMed1997

Clinical application of hepatic venous hemodynamics by Doppler ultrasonography in chronic liver disease.

The phase differences of the hepatic vein (HV) Doppler waveform might be influenced by fibrosis and steatosis of the liver when using HV Doppler and pressure curve analysis. Because HV catheterization is invasive, we have advocated the noninvasive comparative index (QXs ratio) of the HV Doppler waveform phases recorded simultaneously with electrocardiography and phgonocardiography. Forty-three controls and 169 patients with a variety of liver diseases were enrolled in this study. The mean QXs ratio was 0.75 in the controls, 0.6 in the chronic hepatitis patients, 0.45 in the cirrhosis patients, and 0.90 in the fatty liver patients. There were significant differences between all pairs of these groups (p < 0.001). The QXs ratio may be used to assess the degree of hepatic fibrosis or steatosis.

Adult↗
PubMed1997

Phase shift of the hepatic vein flow velocity waveform in chronic liver disease: experimental and clinical studies.

We examined animal models and studied patients with chronic liver disease to evaluate phase shift of the flow-velocity waveform of the hepatic vein (HV). We decided the Doppler-Pressure (DP) ratio using electrocardiography, the HV Doppler waveform and HV pressure curves, and we calculated the DP ratios. In animal models, the mean DP ratio was 1.04 in controls, 0.68 in cirrhosis, and 1.22 in fatty liver. There were significant differences among these groups (p < 0.005). In the clinical study, the mean DP ratio was 1.03 in controls, 0.95 in chronic hepatitis and 0.79 in cirrhosis. The DP ratio in the Cirrhosis Group was significantly different from that in the Control Group (p < 0.001) and that in the Chronic Hepatitis Group (p < 0.05). We conclude that the DP ratio is decreased in certain hepatic disease states.

Adult↗
PubMed1997

Gray-scale second harmonic imaging of the liver with galactose-based microbubbles.

RATIONALE AND OBJECTIVES: The authors evaluate the efficacy of SHU 508A, a galactose-based contrast agent used in gray-scale second harmonic imaging in vitro and in vivo experiments. METHODS: A Toshiba prototype harmonic imaging system (2.5/5.0 MHz) was used with SHU 508A in a phantom experiment and to image the liver in five healthy rabbits and one rabbit that had VX-2 tumors in the liver. RESULTS: In the second harmonic imaging, most of the fundamental components of the backscattered echo were eliminated, and good images with high contrast were obtained in the phantom experiment. Liver parenchyma was enhanced clearly in all rabbits at 0.3 mL/kg, an effect that lasted for 90 seconds. The tumor, which was mostly necrotic, was depicted clearly as a negative enhanced area surrounded by enhanced healthy liver. CONCLUSIONS: Gray-scale second harmonic imaging is a promising new method for visualization of perfusion of organs.

Animals↗
PubMed1997

Sonographic detection of tumor blood flow using a new contrast agent in woodchuck hepatomas.

The aim of this study was to assess the ability of perfluoropropane-filled albumin microspheres to visualize tumor blood flow in woodchuck hepatomas. Ten tumors in five woodchucks with hepatomas were imaged before and after intravenous injection (dosages of 0.01 ml/kg to 2.0 ml/kg) of an agent using color Doppler sonography and gray scale ultrasonography. Both enhanced imaging modalities demonstrated blood flow around and within all tumors. Enhanced gray scale ultrasonography demonstrated sonographic "tumor blush" in seven tumors (70%). In conclusion, tumor blood flow in woodchucks was visualized more clearly using the agent on both color Doppler and gray scale ultrasonography.

Albumins↗
PubMed1997

Hepatic arterial complications in pediatric segmental liver transplantations from living donors: assessment with color Doppler ultrasonography.

To investigate the clinical utility of color Doppler ultrasonography in detecting hepatic arterial complications in pediatric living-related liver transplantation, we studied peak systolic velocity (Vp) and pulsatility index (PI) intrahepatic artery during and after surgery in 122 transplants. Six cases with hepatic artery thrombosis were detected by Doppler studies. In 2 cases with dampened waveforms at intraoperative flowmetry (Vp < or = 23 and PI < or = 0.6), thrombosis occurred soon after surgery. A further 2 cases had a rapid decrease in Vp and PI values postoperatively, leading to absence of arterial signals. Follow-up Doppler studies suspected collateral formation after thrombosis in 2 survivors. Normal Doppler waveforms were obtained in all of the 116 cases without arterial complications. Among them, 6 cases had absent signals or dampened waveforms at initial intraoperative flowmetry (Vp < or = 30 and PI < or = 0.9), and maneuvers such as re-reanastomosis of the artery improved flow signals with an increase in Vp and PI values. Serial intra- and post-operative Doppler examinations are useful for early detection of arterial complications.

Adolescent↗
PubMed1996

Experiences of 120 microsurgical reconstructions of hepatic artery in living related liver transplantation.

BACKGROUND: We reviewed 120 microsurgical reconstructions of a hepatic artery in living related liver transplantation and discussed the problems encountered. METHODS: From January 1991 to July 1994 we performed a series of 105 living related liver transplantations on children with end-stage liver disease. Arterial reconstruction was performed under the optical field of a continuous zoom magnification of approximately 10 times with an operating microscope. RESULTS: Twenty-six percent of the graft arteries were less than 2 mm in diameter. The time required for an arterial reconstruction was 49.5 +/- 1.8 minutes. In 15 of the 31 cases in which there were two graft arteries, two arterial reconstructions were required. The caliber differences between the graft artery and the recipient artery in 30 instances was dealt with by cutting an undersized artery obliquely (17 instances), by fish-mouth method (10 instances), by end-to-side anastomosis (1 instance), or by funnelization method (2 instances). In one case we performed an intimal dissection of a recipient hepatic artery and substituted a splenic artery. Consequently, hepatic arterial thrombosis occurred in only two cases (1.7%). CONCLUSIONS: Microsurgical technique has overcome the high risk of hepatic arterial thrombosis in cases of fine graft arteries, enabled the reconstruction of arteries with caliber difference, and decreased arterial complications with its delicate manipulation.

Adolescent↗
PubMed1995

Influence of spontaneous portosystemic collateral pathways on portal hemodynamics in living-related liver transplantation in children. Doppler ultrasonographic study.

We investigated the influence of spontaneous portosystemic collateral pathways on the portal hemodynamics and examined the necessity for ligating these vessels in pediatric liver transplantation from living donors. We assessed portal blood flow before, during, and after surgery in 82 pediatric recipients (mean age, 4.2 years), using Doppler ultrasonography. When blood flow in the reconstructed portal vein was decreased (< 10 ml/min/kg body weight) and portosystemic collaterals persisted during surgery, those vessels were ligated and Doppler flowmetry was examined again. Spontaneous portosystemic collaterals were detected at one or more sites in 67 patients before transplantation. These collaterals had been ligated in 17 patients before intraoperative flowmetry. Among the remaining 50 patients, initial Doppler studies revealed a decrease in portal blood flow in 22 patients. Nine patients had hepatofugal splenic venous flow and 6 had no significant flow signals from the intrahepatic portal vein. Ligation of collaterals resulted in a remarkable increase in portal blood flow in 20 patients, all of whom are alive. The remaining 2 patients died of graft failure due in part to portal hypoperfusion. On the other hand, the collaterals were not ligated in 24 patients because adequate portal blood flow was confirmed by intraoperative flowmetry. Postoperatively, flow signals from the unligated collateral vessels gradually diminished, but they still persisted in 3 patients at 12 months after transplantation. Hepatofugal blood flow through the portosystemic collateral pathways may persist after implantation of a normal graft. If the patent collaterals significantly reduce the effective portal blood flow, these vessels should be ligated in order to avoid graft failure.

Adolescent↗
PubMed1995

Evaluation of protective effects of prostaglandin E1 on ischemic liver damage with in vivo 31P-MR spectroscopy.

The cytoprotective effect of prostaglandins (PG) was evaluated by in vivo 31P MR spectroscopy. Twenty rabbits were divided into two groups; the control group given physiological saline, and the PG group given prostaglandin E1 (0.5 microgram/kg/min). Each solution was infused for 8 min, after which complete hepatic ischemia was induced for 20 min, followed by reperfusion for 40 min. During ischemia, beta-ATP decreased to 23.6% and 42.3%, phosphomonoester increased to 260% and 200% of their initial values in the control and the PG groups, respectively. Inorganic phosphate also increased. After reperfusion, beta-ATP recovered to 65.2% and 96.5%, phosphomonoester to 130% and 110%, inorganic phosphate to 140% and 120% in the control and PG groups, respectively. The changes during ischemia were significantly smaller and the recoveries during reperfusion were more complete in the PG group. These results may confirm the cytoprotective effect of prostaglandins by in vivo 31P-MR spectroscopy.

Adenosine Triphosphate↗
PubMed1995

Recovery of graft circulation following percutaneous transluminal angioplasty for stenotic venous complications in pediatric liver transplantation: assessment with Doppler ultrasound.

Percutaneous transluminal angioplasty was performed for venous stenosis after living related liver transplantation in three children. Two of them had hepatic vein stenosis and one had stenosis of both the hepatic and portal veins. Progressive development of ascites and deterioration of liver function were found in all cases. Serial Doppler ultrasound studies showed that the flow velocity in the hepatic vein gradually decreased with a flattened velocity waveform, followed by a decrease in portal blood flow. After a successful hepatic vein angioplasty, the velocity in the hepatic and portal veins increased and the Doppler waveform in the hepatic vein became pulsatile in two cases. In the remaining case, a remarkable recovery of both graft perfusion and clinical findings was achieved via combined hepatic vein and portal vein angioplasty. We conclude that balloon angioplasty is an effective alternative to surgery for post-transplant vascular stenosis and that Doppler ultrasound is useful in monitoring graft circulation.

Angioplasty, Balloon↗
PubMed1995

Vascular complications in living related liver transplantation detected with intraoperative and postoperative Doppler US.

BACKGROUND/AIMS: The purpose of this study was to clarify changes in the graft hemodynamics induced by vascular complications in living related liver transplantation. METHODS: This study included 46 pediatric recipients who underwent partial liver transplantation from living related donors. The blood flow was evaluated in the portal system, the hepatic artery and the hepatic vein with serial intra- and post-operative Doppler ultrasound (US). RESULTS: In 12 patients, intraoperative Doppler US showed a decrease in portal venous inflow (< 9 ml.min-1.kg-1) toward the liver graft and could act as a guide for ligation of collaterals in seven patients, portal re-construction in two, thrombectomy in one and relief of hepatic venous outflow obstruction in two for increasing the portal venous inflow. In five patients, intraoperative Doppler US showed poor arterial inflow, i.e. dampened arterial waveforms which involved both low pulsatility index (< 0.90) and low peak-systolic velocity (< 31 cm/s). In three of them, the waveform was more pulsatile after re-anastomosis or relief from stretching of the hepatic artery. The remaining two patients developed hepatic artery thrombosis. Most of the hepatic venous outflow obstruction (four of five patients) had flat waveforms, low flow velocity (< 10 cm/s) of the hepatic vein, and poor portal inflow (flow velocity < 14 cm/s). Postoperative Doppler US showed hepatic venous outflow obstruction in three patients, hepatic artery thrombosis in three (twice in one patient), portal vein stenosis in two and portal vein thrombosis in one. These complications were successfully managed with surgical procedures in three patients, transhepatic angioplasty in three and conservative treatments in four. Six patients died of non-vascular complications. CONCLUSIONS: Serial intra- and post-operative Doppler US was a useful technique for making an early diagnosis of abnormal hemodynamics of the graft circulation. Furthermore, intraoperative Doppler US could assess reconstructed vessels objectively and would reduce the incidence of vascular complications following transplantation.

Adolescent↗
PubMed1995

Azygos venous blood flow: measurement with direct bolus imaging.

PURPOSE: To evaluate a magnetic resonance (MR) imaging technique for measurement of azygos blood flow volume, which is an important indicator of superior collateral circulation in patients with portal hypertension. MATERIALS AND METHODS: Azygos blood flow was measured by means of direct bolus (DB) imaging, an MR flow measurement technique. A presaturation pulse was applied in combination with electrocardiographic gating. RESULTS: The measured flow volume was 320 mL/min +/- 30 (mean +/- standard error of mean) in the control subjects, 550 mL/min +/- 130 in patients with cirrhosis of the liver and without varices, and 660 mL/min +/- 60 in patients with cirrhosis of the liver and with varices. The flow volume was significantly higher in each of the groups with cirrhosis of the liver than in the control group (P < .01). Furthermore, a significant correlation was shown between DB imaging and continuous thermodilution measurements (r = .707, P < .01). CONCLUSION: DB imaging, which is noninvasive, was useful in the monitoring of the effect of treatment and in determination of the prognosis in patients with portal hypertension.

Aged↗
PubMed1994

Pneumonitis associated with natural and recombinant interferon alfa therapy for chronic hepatitis C.

We report three cases of chronic hepatitis C (HC) with pneumonitis, suspected to be caused by natural and recombinant interferon (INF) alfa treatments. The patients were administered INF through intramuscular injection. All three patients developed acute respiratory failure (PaO2 < or = 60 mm Hg) with bilateral lung infiltration. One of the patient's condition improved after the cessation of INF treatment, without any other therapy. The other two patients were administered corticosteroids, and one patient's condition improved, while in the other patient the pneumonitis persisted, even after a high dose of corticosteroids. To our knowledge, these three cases are the first report of pneumonitis associated with INF alfa in patients with chronic HC.

Aged↗
PubMed1994

Color Doppler sonography of hepatic tumors with a galactose-based contrast agent: correlation with angiographic findings.

OBJECTIVE: The purpose of this study was to evaluate the clinical usefulness of a galactose-based, IV sonographic contrast agent for assessing tumor vascularity and diagnosing hepatocellular carcinoma. SUBJECTS AND METHODS: We used color Doppler sonography with the sonographic contrast agent to examine 22 patients with 26 hepatic nodules (18 hepatocellular carcinomas, four hemangiomas, two adenomatous hyperplasias, and two metastatic tumors). In all 26 lesions, intratumoral arterial flow signals were examined before and after IV injection of the sonographic contrast agent at three concentrations (200, 300, and 400 mg/ml), and the findings on color Doppler sonograms of each lesion were correlated with angiographic findings. RESULTS: Conventional color Doppler sonograms showed flow in nine hepatocellular carcinomas (50%) and one hemangioma (25%). When the contrast agent was used, color Doppler sonograms showed intratumoral arterial flow in 11 hepatocellular carcinomas (61%) and one hemangioma (25%) at a concentration of 200 mg/ml, in 14 hepatocellular carcinomas (78%) and 1 hemangioma (25%) at 300 mg/ml, and in 15 hepatocellular carcinomas (83%) and two hemangiomas (50%) at 400 mg/ml. The detectability of intratumoral arterial flow was improved by the contrast agent, especially in hepatocellular carcinomas smaller than 30 mm in diameter. Angiography revealed neovascularization or staining in 15 hepatocellular carcinomas, four hemangiomas, and none of the adenomatous hyperplasias or metastatic tumors. Among 15 angiographically hypervascular hepatocellular carcinomas, the detection rate of intratumoral arterial flow with contrast-enhanced color Doppler sonography was 73% at 200 mg/ml, 93% at 300 mg/ml, and 100% at 400 mg/ml. No intratumoral Doppler signals were depicted with the use of contrast agent in any angiographically undetected tumors. CONCLUSION: Preliminary findings on contrast-enhanced color Doppler sonograms correlate well with angiographic findings for evaluating tumor vascularity. This noninvasive technique may be useful in diagnosing hypervascular hepatocellular carcinomas.

Adenoma↗
PubMed1994

Effects of dobutamine on hepatosplanchnic hemodynamics in patients with chronic liver disease.

BACKGROUND: It is said that catecholamines increase hepatic blood flow in patients without liver diseases, although several reports have suggested a blunted response to catecholamines in patients with liver cirrhosis. METHODS: We investigated changes in splanchnic blood flow distribution induced by the infusion of dobutamine into peripheral veins of healthy adults (NC group), patients with chronic hepatitis (CH group), and patients with liver cirrhosis (LC group), using a Doppler duplex system (protocol 1). We also investigated changes in hepatic hemodynamics induced by dobutamine infusion in patients with liver cirrhosis (cirrhosis group) and patients without liver diseases (control group), using hepatic catheterization (protocol 2). RESULTS: In protocol 1 the average increase in portal venous blood flow during dobutamine infusion was significant in the NC and CH groups but was not significant in the LC group. Changes in the blood flow in the splenic artery and vein, superior mesenteric artery and vein, and femoral artery were similar to those in the portal vein in each of the three groups. Infusion did not cause a change in the common hepatic arterial flow in any of the three groups. In protocol 2 the portal venous flow, cardiac index, and hepatic venous pressure gradient increased significantly during dobutamine infusion in both the cirrhosis and the control groups. Hepatic vascular resistance in the cirrhosis group increased slightly, whereas, in contrast, that in the control group increased significantly. The rate of change in almost all variables was lower in the cirrhosis group than in the control group. CONCLUSION: These results indicate that dobutamine has less effect on hepatic circulation in patients with liver cirrhosis than in those without liver diseases, indicating that the value of dobutamine in increasing hepatic blood flow in cirrhotic patients is very limited.

Aged↗