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Biomedical subjects

M Onoe

Publications and source records attributed to M Onoe.

88 records · Page 5Linked to original sources
PubMed1984

[Computerized processing of two-dimensional echo-cardiograms: its application for quantitating left ventricular regional contractility and three-dimensional echocardiography].

This study assessed the computerized processing of two-dimensional echocardiograms for quantitating left ventricular regional contractility and for computer reconstruction of the left ventricle; so-called three-dimensional echocardiography. Computer analysis of two-dimensional echocardiograms for quantitative evaluations of the left ventricular regional contractility in myocardial infarction: A new practical method for computer digital image processing of two-dimensional echocardiograms was developed for quantitating left ventricular regional contractility. Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve (MV), papillary muscles (PM) and the apex (AP) were recorded using a phased array sector scanner in thirty patients with healed myocardial infarction and fifteen normal control subjects. The echocardiographic data were recorded on the video tape and transferred to a minicomputer via interface circuits, digitized, and processed automatically. Each digitized image consisted of 256 X 256 pixels with a gray scale of 256 values. The edges of the endocardial and epicardial walls were detected by applying sequential steps including smoothing, dynamic thresholding, region growing, and filling of small holes. The rationale of edge detection depended on assuming that abrupt changes in gray levels occurred at the boundary, and that the points with maximum gradient values were boundaries of the left ventricular wall. Best-fit contours of endocardial and epicardial edges were drawn by fitting a spline. Besides this automatic edge tracing, endocardial and epicardial edges were also manually traced using a digi-pen system, whose results coincided well with automatic tracings. After detection of edges of endocardial and epicardial walls, the short-axis cross sectional left ventricular wall at each level was divided into eight segments. The geometric center of the end-diastolic left ventricular cavity and the axis connecting this with the posterior end of the right side of the septum was used as the reference point and line (fixed reference system). End-diastolic and end-systolic segmental hemiaxes, segmental area, segmental wall thickness and changes during the cardiac cycle were measured and calculated automatically in each segment using a computer. Regional contractility of the left ventricle was evaluated by percent systolic changes of the segmental hemiaxis, area and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and coronary angiography.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Three dimensional reconstruction of the left ventricle from multiple cross sectional echocardiograms. Value for measuring left ventricular volume.

The accuracy of a system for reconstructing a three dimensional image of the left ventricle from randomly recorded multiple short axis images was tested by comparing the calculated left ventricular volume with the directly measured left ventricular volume in 11 excised porcine hearts. The system comprised a real time phased array sector scanner, a transducer locating system, and a computer system for digitising outlines of the left ventricle, displaying the reconstruction image, and calculating the left ventricular volume. The reconstructed image was similar to the real image and the calculated left ventricular volume showed a high correlation with the directly measured left ventricular volume. This method was accurate in vitro and is expected to be available for clinical measurement of left ventricular volume.

Animals↗
PubMed1982

[Computer analysis of wo-dimensional echocardiogram for the quantitative evaluation of left ventricular asynergy in myocardial infarction].

Quantitative assessment of left ventricular asynergy in myocardial infarction was made by computer analysis of the two-dimensional echocardiogram. Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscle and apex were recorded by a phased array sector scanner in 20 patients with myocardial infarction and ten normal controls. End cardial and epicardial outlines at end-diastole and end-systole were traced and analyzed by a computer system. Short-axis cross-sectional images of the left ventricle were divided equally into octants and analyzed with a fixed external reference system, using the center of gravity of end-diastolic left ventricular cavity and the axis intersecting this and the right side of the posterior interventricular septum as the reference point and line. Segmental hemiaxis, area, wall thickness and those changes during cardiac cycle were measured and calculated in each octants. Regional contractility of the left ventricle was evaluated by systolic percent change of segmental hemiaxis, area and wall thickness. These parameters were significantly reduced in the infarcted segments documented by left ventriculography and electrocardiography. The area method is better than the hemiaxis system in both reproducibility and variability. The center of gravity of the left ventricular cavity determined by the computer shifted slightly towards the anterior wall during systole in normal subjects, possibly reflecting anterior swinging motion of the entire heart. The center of the gravity of the left ventricular cavity in myocardial infarction showed the tendency to shift towards the infarcted region, suggesting the possibility that the location of asynergic area can be detected by determining the direction of the gravity center shift during systole in patients with a single infarction. This finding gives a basis of using the fixed reference system for the detection of asynergy. The use of computers for the analysis of short-axis two-dimensional echocardiographic images is very useful for the quantification of regional contractility of the left ventricle in a clinical setting.

Computers↗
PubMed1981

[Digital image processing of the two-dimensional echocardiogram for the evaluation of regional contractility of the left ventricular wall (author's transl)].

Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscles and apex were recorded on video tape by using a phased-array sector scanner. Endocardial and epicardial outlines of the cross-sectional left ventricular wall were determined automatically by a computer tracing process including digital image processing system. Short axis cross-sectional left ventricular walls of upper-, middle- and lower parts of the left ventricle were divided into eight segments, the center of gravity of end-diastolic left ventricular cavity being used as the reference point. Various parameters such as segmental radius, segmental wall thickness, cross-sectional area, left ventricular circumference and those changes during the cardiac cycle were determined in eight segments at three levels of the left ventricle. Regional contractility of the left ventricular wall was evaluated by systolic shortening of segmental radius and systolic thickening of segmental wall thickness. Contractility and pumping function of the overall left ventricle was assessed by shortening velocity of left ventricular circumference and fractional changes of cross-sectional area at three levels of the left ventricle. These were significantly and diffusely reduced in a patient with congestive cardiomyopathy (CCM), contrasting with a normal subject. Systolic changes in segmental radius and segmental wall thickness were significantly reduced in infarcted myocardium. Digital image processing system and segmental analysis of the left ventricular short-axis two-dimensional echocardiogram are very useful to evaluate the regional contractility of the left ventricle, quantitatively and automatically, especially in patients with myocardial disease including CCM and myocardial infarction with left ventricular asynergy.

Computers↗
PubMedDate not supplied

Supravalvular stenotic mitral ring with ventricular septal defect.

BACKGROUND: Supravalvular mitral ring is exceedingly uncommon. METHODS: We report a 4-year-old girl with supravalvular stenotic mitral ring and ventricular septal defect (VSD). The VSD was closed by a Dacron patch and the supravalvular ring was excised. For treatment of supravalvular mitral ring with obstruction, surgical resection is commonly performed. RESULTS: There are no reports of long-term follow-up after resecting the supravalvular mitral ring. CONCLUSION: In our case, no mitral stenosis was evident on postoperative echocardiogram performed 3 years after surgery.

Child, Preschool↗
PubMedDate not supplied

Refractoriness to platelet transfusion following double valve replacement in an ITP patient who had undergone splenectomy.

Reports of patients with idiopathic thrombocytopenic purpura (ITP) undergoing cardiac surgery are rare, and almost all of the reported cases required platelet transfusion. ITP patients, especially those having a history of splenectomy or a history of heavy bleeding, may have to undergo multiple platelet transfusions. Such transfusions may induce alloimmunization against the human leukocyte antigen (HLA) and result in refractoriness to subsequent platelet transfusions. We report a case of a 63-year-old female with ITP, with a history of splenectomy and multiple platelet transfusions, who underwent aortic and mitral valve replacement. Although corticosteroid administration, high-dose immunoglobulin therapy, and repeated platelet transfusion led to a temporary increase in platelet count and successful hemostasis, refractoriness to platelet transfusion occurred postoperatively because of the presence of the anti-HLA antibody. In addition, the patient showed complications of pyothorax. Corticosteroids might have exerted an inhibitory influence on the occurrence of pyothorax.

Aortic Valve↗
PubMedDate not supplied

Disseminated cholesterol embolism after coronary artery bypass grafting.

Blue toe syndrome caused by cholesterol emboli is a relatively benign disease. However, disseminated cholesterol embolism is a life-threatening condition. We describe here the case of a 71-year-old female admitted because of anterior chest pain and intermittent claudication. Following cardiac catheterization, warfarin potassium was administered. However, the patient's toes soon darkened bilaterally, and BUN and creatinine levels increased from the normal value. Skin discoloration and renal failure were improved after stopping warfarin potassium administration. The patient underwent coronary artery bypass grafting and left femoropopliteal bypass. Cerebral infarction and renal failure occurred postoperatively due to disseminated cholesterol embolism. The patient died from renal failure on the 16th postoperative day without regaining consciousness following surgery. For high risk patients, interventional procedures to the ascending aorta must be avoided. When CABG cannot be avoided for coronary revascularization, off-pump bypass and use of arterial grafts are recommended.

Aged↗
PubMedDate not supplied

Effects of pulsatile cardiopulmonary bypass on carbohydrate and lipid metabolism.

The influence of pulsatile perfusion on carbohydrate and lipid metabolism was examined in 40 patients (20 pulsatile and 20 non-pulsatile) who underwent open-heart surgery. The pulsatile assist device was used for pulsatile cardiopulmonary bypass during aortic cross-clamping only, and samples of the mixed venous blood were taken every 20 minutes. There were no statistically significant differences between pulsatile and non-pulsatile groups with respect to plasma levels of glucose, insulin, glucagon, free fatty acids and ketone bodies. However, an increase in the plasma level of noradrenaline was significantly suppressed in the pulsatile group, and triglyceride levels were significantly higher in the pulsatile than in the non-pulsatile group. These data suggest that pulsatile flow attenuates the catecholamine stress response to cardiopulmonary bypass and has a protective effect on liver function during bypass.

Adolescent↗