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Biomedical subjects

T Kozuka

Publications and source records attributed to T Kozuka.

At least 325 records · Page 18Linked to original sources
PubMed1983

[Late results of coronary heart surgery. Late graft patency in coronary bypass procedure].

The graft patency was evaluated by a contrast enhanced computed tomography (CT) and/or digital subtraction angiography (DSA) in the follow up of aorto-coronary bypass surgery. One hundred and eighty-four patients included in this study received a total of 331 grafts. The Elipse S/200 Scanner for CT and Siemens Angiotron system for DSA were used for this study. Early in the study, selective coronary angiography were performed and the results were interpreted in 331 grafts and 86 grafts to evaluate the diagnostic reliability of CT and DSA for graft patency, respectively. While the CT scans correlated with angiographic assessment of graft patency showed 98% of sensitivity, 100% of specificity, and 98% of predicted accuracy, the DSA showed 95% of sensitivity, 100% of specificity and 95% of predicted accuracy, respectively. The patency rate in the early postoperative period was 94%, and the cumulative patency rate during follow up of 5 years was 93%, respectively. In summary, CT and DSA can provide useful information regarding graft patency in the long term follow up of aorto-coronary bypass surgery.

Adult↗
PubMed1983

[Diagnosis of dissecting aortic aneurysm by digital subtraction angiography].

The aim of the study was to determine whether digital subtraction angiography (DSA) can be used in the diagnosis of aortic dissection. The study group consisted of six patients with aortic dissection including one of type 2 and five of type 3 by the DeBakey classification. DSA findings were compared to cineangiographic findings. The results were as follows; In all the patients, the diagnosis of aortic dissection was possible using DSA. Especially as to the entry, which was not detected by other non-invasive methods, there was an excellent correlation between cineangiograms and DSA (sensitivity 100%). Of the 20 vessels in the abdomen, which included the celiac, superior mesenteric, and right and left renal arteries, three vessels (15%) were not identified by DSA. Causes of the failure were the low spatial resolution and the artifact due to the motion of the patients and intestinal gas movement. The accuracy rate of the abdominal branch involvement was 70%. While using a prototype equipment, the preliminary study showed that DSA is a safe and very useful method not only for diagnosing aortic dissection, but for evaluation of the entry, extension of the dissection, and involvement of major branches of the abdominal aorta and for a follow-up study.

Adult↗
PubMed1983

[Application of computed tomography to cardiovascular system: present status and perspective].

In spite of major limitation in the application of computerized transmission tomography to the cardiovascular system, it has several unique advantages. The aim of this lecture is to give the recent advance and perspective of cardiac CT examination. The advantages include excellent spatial and contrast resolution and obtaining three dimensional images of the heart and the great vessels. Although CT scanning of the heart without contrast medium provides vague differentiation of the cardiac structures, with contrast medium injection it gives more precise information. Rapid sequential scanning with table movement may be useful to give tomographic images covering the whole heart. Since temporal resolution is improved with rapid sequential scanning at the fixed position, functional analysis of the cardiovascular system in a slice, for example patency of the aorto-coronary bypass graft, can be easily examined with excellent accuracy. ECG-gated scanning provides anatomical information with good temporal resolution, as well as functional values, such as left ventricular mass, left ventricular volume, left ventricular ejection fraction and cardiac output. These values obtained from cardiac CT showed a good correlation with the values from cine left ventriculography and a dye-dilution study. Thrombi or tumors in the cardiovascular lumen could be detected with CT examination. Attenuation of left ventricular wall motion, thinning of the ventricular wall and reduced regional myocardial thickness seemed to be major landmarks for computed tomographic diagnosis in ischemic heart disease. Cardiac CT examination may give the comparable information with echocardiography in this field. In the future, ultra-fast CT scanners will be developed to give the multiple section capacity for three dimensional imaging and to improve temporal resolution for cardiac functional analysis.

Cardiac Output↗
PubMed1983

[Evaluation of pulmonary regurgitation with a catheter-tip electromagnetic velocity probe].

Pulmonary regurgitation appeared after the surgical repair of pulmonary stenosis was investigated with an electromagnetic catheter-tip velocity probe in seven patients. Postoperative catheterization was performed by placing the probe in the pulmonary trunk transvenously and a velocity curve was recorded on a photographic recorder at a paper speed of 150 or 200 mm/sec with electrocardiograms and pulmonary arterial pressure pulse. The velocity curves were recorded under the baseline throughout diastole in patients with pulmonary regurgitation, while the curves in the normal controls were just on the baseline. The amount of regurgitation was evaluated with the ratio of the negative to positive area of velocity curves. The negative area (NA) was defined as an area circumscribed by the diastolic negative velocity curve and the baseline, and the positive area (PA) as an area circumscribed by the systolic positive curve and the baseline. The amount of the regurgitation was also evaluated from either the pulmonary cineangiogram or the volume measurement using the right arteriogram. The results were as follows: The severity of pulmonary regurgitation estimated by the pulmonary arteriogram (grade I to III) tended to be correlated with the ratio of the NA/PA. Right ventricular end-diastolic volume index (RVEDVI) and the NA/PA showed a fair correlation with a coefficient of 0.80. Right ventricular volume overload resulting from pulmonary regurgitation was reflected on the NA/PA. The subtraction of right and left ventricular systolic ejection indices (RVSI-LVSI) or its ratio (RVSI-LVSI)/RVSI, which were considered as the indices of the severity of pulmonary regurgitation from the volume measurement, had fairly good a correlation with the NA/PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

[Measurement of four chambers' volumes and ventricular masses by cardiac CT examination].

Using cardiac computed tomography (CT), the "mean" volume of each cardiac chamber and both ventricular masses were calculated from summation of a sliced volume by ungated scans obtained using rapid sequential scanning covering the whole heart. Estimation of a normal value of each chamber's volume was attempted in 20 patients with ischemic heart disease and with normal heart function. The "mean" volume of the right atrium (RAMV), right ventricle (RVMV), and left atrium (LAMV) was 22.3 +/- 6.5, 40.3 +/- 6.5 and 28.7 +/- 8.2 ml/m2, respectively. In 54 patients with valvular heart diseases, each chamber's volume obtained by CT was compared with the grade of tricuspid regurgitation (TR) estimated by ultrasonic Doppler technique or the grade of mitral regurgitation (MR) by left ventriculography (LVG). The RAMV (234 +/- 119 ml/m2) and the RVMV (101 +/- 39 ml/m2) were markedly increased in patients with severe TR (grade 3 to 4) (p less than 0.01). The LAMV (487 +/- 231 ml/m2) was also increased in patients with severe mitral regurgitation (grade 3 to 4) (p less than 0.01). In 46 patients with valvular heart diseases, the LVMV by CT was well correlated with end-diastolic volume (EDV) obtained by LVG (r = 0.92), and the LVEDVs by ECG gated CT and by LVG showed a fairly good correlation (r = 0.95). CT examination was performed before and after surgery in 17 patients with MR or TR for evaluation of the change of chamber volumes. The mean reduction ratio (MRR) of the RAMV after tricuspid annuloplasty, the LVMV after mitral valve plasty, and the LAMV after left atrial plication was 44%, 41%, and 60%, respectively.

Cardiac Volume↗
PubMed1982

Evaluation of tricuspid regurgitation by pulsed Doppler and two-dimensional echocardiography.

We analyzed tricuspid regurgitation noninvasively using ultrasonic pulsed Doppler and two-dimensional echocardiography in 66 patients in whom tricuspid regurgitation was suspected from routine clinical evaluation. All of the patients also underwent right ventriculography. Ten healthy subjects served as controls. In 62 of 66 patients, the study was adequately performed. In 58 of 62 patients, pansystolic abnormal Doppler signals were detected in the right atrial cavity, and were interpreted to indicate tricuspid regurgitant flow. Two-dimensional echocardiograms in the parasternal four-chamber view demonstrated that the region in which the abnormal Doppler signals were detected was spindle-shaped and extended from the tricuspid orifice toward the right atrial posterior wall parallel to the interatrial septum. The severity of regurgitation was graded on a four-point scale, based on the distance reached by the abnormal signals from the tricuspid orifice toward the posterior wall. For comparison, the right ventriculograms were evaluated on a four-point scale similar to the Sellers classification of mitral regurgitation. The grades by the two methods matched exactly in 36 cases, differed by one level in 23 and by two levels in three. Thus, the two methods showed a good correspondence. Similar results were obtained for the grading based on the area covered by the abnormal signals. We conclude that noninvasive grading of tricuspid regurgitation by ultrasonic pulsed Doppler and two-dimensional echocardiography is practicable.

Adult↗