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Biomedical subjects

T Kozuka

Publications and source records attributed to T Kozuka.

At least 343 records · Page 19Linked to original sources
PubMed1982

Angiographic consideration of rheumatic mitral valvular disease.

An angiocardiographical analysis of the rheumatic mitral valvular changes was performed on 344 patients examined during the period from October, 1977 to July, 1980. The following results were obtained: 1) In the analysis of the mitral apparatus, the mitral orifice projection which enables us to observe the mitral annulus as en face and the long axial projection enabling us to observe the profile was particularly useful for the diagnostic validity. 2) Mitral orifice projection was useful for the diagnosis of stenosis dominant lesion, while long axial projection was beneficial for the diagnosis of regurgitation dominant lesion. 3) The measurements of mitral apparatus were carried out through these projection methods. It was found that the diameter of annular ring as well as the area of posterior leaflet were markedly increased in the mitral regurgitation group.

Adult↗
PubMed1982

[Evaluation of myocardial ischemia by (RAO) long-axial myocardial imaging using slant-hole collimator].

Myocardial perfusion imaging with thallium chloride has been found to be effective in the clinical evaluation of patients with myocardial infarction. However, conventional myocardial perfusion imaging of the myocardium showing the postero-septal and antero-lateral wall cannot be obtained clearly by the conventional collimator due to the inevitable distance between the collimator and the heart. In contrast, 30, 60-degree RAO images were obtained clearly using slant-hole collimator with the collimator closely contact with the heart, which enables us to observe the postero-septal and antero-lateral walls of the myocardium. As a result, we obtained myocardial perfusion images every 30-degrees in a radial direction. By dividing RAO images into 12 segments, we compared perfusion defect in the myocardial scintigram with akinesis detected by echocardiography and contrast left ventriculography segmentally and referred to the character and accuracy of these three examinations. As a result, these three methods well agreed in cases with myocardial infarction of single vessel disease, but did not always agree in cases with triple vessel disease. The character of each method was as follows: 1) Left ventriculography, which gives direct information concerning wall motion of the left ventricle, was most sensitive to detect ischemic lesions, but had a tendency to overestimate hypokinesis of wall motion due to its invasive nature. 2) In myocardial scintigraphy, when hypoperfusion is associated with perfusion defect, we occasionally diagnose mistakenly the hypoperfusion area as normal because the scintigraphic evaluation is based on the relative distribution of perfusion. To avoid such underestimation, exercise myocardial scintigraphy should be performed and myocardial ischemia should be evaluated by comparing exercise images with redistribution images. Moreover, we studied extension of perfusion defect in the anterior and infero-posterior infarction groups. In anterior myocardial infarction, perfusion defect extended beyond the apex and reached the point one-third away from the apex to the base. In infero-posterior myocardial infarction, perfusion defect extended into the apex but did not exceed the apex. It seemed that the most suitable point to make the boundary between apical and infero-posterior areas was the point one-third away from the apex to the base along the inferior half of the RAO image of the myocardium.

Coronary Disease↗
PubMed1982

[Evaluation of left ventricular wall characteristics in ischemic heart disease by cardiac CT examination].

Sixty-one cases with ischemic heart disease were examined with ECG-gated computed tomography (CT), and left ventricular (LV) wall properties were evaluated by the end-diastolic and end-systolic images of LV slices in terms of LV inner wall motion, LV wall thickness change in cardiac cycle and LV wall thinning. 1) Inner wall motion abnormalities of LV were detected by superimposing ED and ES images, and these coincided with angiocardiographic findings in 82% of LV segments, while assessment was difficult in the septal side because of its poor wall motion even in normal cases. In CT examination, both "hypokinesis" and "dyskinesis" in left ventriculography (LVG) were likely to be expressed as "akinesis" due to poor time resolution, causing difficulty in assessing the severity of abnormality. 2) In CT examination, changes in LV wall thickness during cardiac cycle were easily evaluated, especially in the septal segments. LV segments of a poor thickness change were well correlated with those of the abnormal wall motion assessed by LVG in 72% of LV segments. 3) In CT, LV wall contractility was finally evaluated by the combination of inner wall motion and wall thickness change, and the final assessments agreed with those observed in LVG in 84% of LV segments. 4) LV segments of abnormal motion evaluated by both inner wall motion and wall thickness change in CT image were well correlated with those observed by LVG (75%), and were thought to imply severe myocardial ischemia. 5) A great part of LV segments with wall thinning corresponded to the severely impaired wall motion observed in LVG (83%) and clinically identified myocardial infarction (87%). Wall thinning was well correlated with infarction.

Adult↗
PubMed1982

[Myocardial imaging in patients with Kawasaki disease: exercise stress imaging and serial studies].

Thallium-201 myocardial imaging was performed in 80 children with coronary arterial lesions due to Kawasaki disease in order to assess the value of serial and exercise myocardial imagings. In eight of these children, abnormalities of the image were noted. Twenty children had serial thallium studies with an interval of three to 18 months, and five of these showed changes in the image including appearance of a new perfusion defect in one patient and improvement of perfusion defects in four. These changes of the myocardial image were correlated well with coronary angiographic findings obtained within a few days of the isotope studies. It was noted that the changes of the myocardial image were more frequently observed at relatively recent period recovered from Kawasaki disease. Exercise myocardial imaging using a bicycle ergometer was performed in eight children with coronary arterial lesions. In three an evidence of improvement of the myocardial perfusion was noted immediately after exercise as well as on the delayed image. In one patient, a decrease of the perfusion in the apex and inferior wall was noted immediately after exercise. On the observed image, image of the apex improved but that of the inferior wall remained hypoperfused. Thus thallium-201 myocardial imaging was considered to permit the best noninvasive documentation of ongoing myocardial perfusion abnormalities in patients with Kawasaki disease. Exercise myocardial imaging was found to be useful in differentiating the viable from nonviable myocardium. It was to be emphasized that quantitative evaluation by computer-assisted analysis was particularly valuable in detecting small areas and in a comparison of the myocardial images.

Adolescent↗
PubMed1982

[Evaluation of left ventricular morphology and function by cardiac computed tomographic examination].

Usefulness of cardiac computed tomography (CT) in the evaluation of left ventricular (LV) morphology and function was studied in clinical practice. One hundred and forty-nine adult cases of various heart diseases were examined by GE scanner with ungated scans covering whole LV and ECG-gated scans. In gating examination, "long-axial" and "short-axial" slices were scanned and end-diastolic area (EDA), end-systolic area (ESA) and "mean" area (MA) were obtained in each slices. 1) With regard to LV morphology, wall thickening in HCM and wall thinning and mural thrombus in myocardial infarction were easily visualized. 2) LV "mean" volume (LVMV) was easily calculated from the sum of sliced LV volume of ungated scans. The LVMV was well correlated with end-diastolic volume (EDV) obtained by LV angiocardiography (LVG) (r = 0.91), though the former was somewhat smaller than the latter. EDV by CT obtained after the correction with MA/EDA from gating examination showed a better correlation (r = 0.95) and both EDV showed almost the same value. 3) LV ejection fraction (EF) was calculated by exchanging ESA/EDA to ESV/EDV in "long-axial" and "short-axial" gated slices, and "long-axial" EF, "short-axial" EF and mean of both were well correlated with LVEF of LVG (r = 0.73-0.79). 4) LVEF calculated from "long-axial" EDA and ESA by application of "area-length" method was also correlated with EF of LVG (r = 0.68), but these EDV and ESV were smaller than those of LVG due to shorter long-diameter of LV in CT. 5) LV muscle volume was calculated from sum of sliced muscle volumes of ungated scans covering LV, and LV mass was easily evaluated from LV muscle volume and specific gravity of LV muscle. This LV mass was well correlated with that of LVG (r = 0.90) and the absolute values were almost the same.

Adult↗
PubMed1982

[Myocardial imaging in patients with transposition of the great arteries: comparison between Mustard and Rastelli operations].

Thallium-201 myocardial imaging was performed in 21 patients with transposition of the great arteries (TGA). Thirteen patients were studied before operation, eight patients after Mustard operation and five patients after Rastelli operation. Five patients were studied sequentially before and after the surgery. Each image was compared with hemodynamic and angiographic findings in order to assess the usefulness of this method. In the 13 patients with preoperative TGA, it was possible to differentiate TGA with the intact ventricular septum from TGA with associated anomalies such as patent ductus arteriosus or ventricular septal defect, and also TGA with pulmonary hypertension or pulmonary stenosis from TGA without them by evaluating the degree of thallium uptake in the free wall of the pulmonary ventricle (anatomical left ventricle). The degree of thallium uptake was well correlated with systolic pressure of the pulmonary ventricle (r = 0.98). In the 13 patients with postoperative TGA, it was less correlated with the pulmonary ventricular systolic pressure (r = 0.83). Four cases sequentially studied showed a marked decrease in thallium uptake in the pulmonary ventricle 10 to 16 months after Rastelli operation. But the corrected thallium uptake (thallium activity/ventricular systolic pressure) was more increased compared with the uptake of the systemic ventricle after the surgery. This was probably related to a decrease of the pressure load to the pulmonary ventricle following the surgery and to the fact that there should be some delay of a decrease of the ventricular mass. An increased lung uptake of thallium was noted in the cases of tricuspid regurgitation after Mustard operation, but the degree of regurgitation was not clearly correlated with the increase of thallium uptake in the lung. In five cases after Rastelli operation, one patient showed a high degree of thallium uptake of the pulmonary ventricle (anatomical right ventricle), and the conduit valve calcification and severe pulmonary stenosis were confirmed by cardiac catheterization and angiography. Thus myocardial imaging provides a reliable mean for the qualitative and quantitative assessment of TGA before and after operation.

Child, Preschool↗