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Biomedical subjects

G Osakada

Publications and source records attributed to G Osakada.

At least 19 recordsLinked to original sources
PubMed1995

Transesophageal echocardiography in the diagnosis of thoracic saccular aortic aneurysm. The value of transesophageal echocardiography during the course of treatment.

Transesophageal echocardiography (TEE) was performed in 17 cases of aortic aneurysms referred to our hospital for further examination and treatment. All 17 cases were treated surgically and TEE was performed as a preoperative examination. In nine of the 17 cases, there were already some signs of bleeding upon admission and in all of these nine cases, rupture of the aneurysm was confirmed during surgery. Measurement on cross-sectional TEE imaging disclosed large aneurysmal diameters in eight of these nine cases, suggesting a close relationship between diameter and rupture. Moreover, observation of the lesions by TEE suggested a relationship between the risk of rupture and morphological characteristics of the thrombus. In seven of the nine bleeding cases, TEE imaging revealed destructive features of the aneurysmal thrombus, such as exfoliation from the aortic wall and/or tearing-off, suggesting expansion of the aortic diameter. Detailed findings of the aneurysm and thrombus on TEE corresponded with surgical findings. Thus, we concluded that TEE is a useful method of obtaining information about aortic aneurysms not only as a preoperative examination but also as an independent examination to determine treatment options and prognosis.

Aged↗
PubMed1992

[The pitfalls in the clinical diagnosis of dissecting aortic aneurysm].

It is sometimes very difficult to diagnose dissecting aortic aneurysms (DAA), particularly in its early stage, due to manifold signs and symptoms. The purpose of this study is to clarify the reasons for such erroneous diagnoses. A total of 41 patients with DAA were referred to our hospitals for further examination and/or surgery from April 1986 to August 1989. In 18 of these patients, the diagnostic possibility of an underlying DAA was overlooked by the referring physicians. Among these 18 patients, 2 were mistakenly diagnosed as uncomplicated myocardial infarction (MI), one as pneumonia, 2 as cerebral infarction, 6 as acute abdominal disease, one as cholelithiasis, 5 as thrombosis of the lower extremities, and one as malignant metastasis to the pericardium. The following is the detail: In 2 cases thought to be uncomplicated MI, an expanding dissecting ascending aorta had crushed the lumen of the left coronary artery, causing MI, in turn, wasting clinical treatment and consuming precious time. In one case, enlargement of the descending aorta on the chest radiography was overlooked and the patient's symptoms were mistakenly attributed to pneumonia. In 2 cases in which symptoms of cerebral ischemia were thought to be attributed to cerebral thrombosis, the real cause turned out to be occlusion of the brachiocephalic artery following aortic dissection. Among 6 cases which were initially considered to have only acute abdominal disease, 3 presented with symptoms and signs of ileus, and their exploratory laparotomies yielded no positive findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Transesophageal Doppler echocardiography in the diagnosis of atrial septal defect].

To assess the usefulness of transesophageal Doppler echocardiography (TEE) in diagnosing atrial septal defect (ASD), we studied eight cases with secundum type ASD, in which the diagnosis was confirmed by cardiac catheterization and surgery. In all cases, TEE provided clear images of the interatrial septum with its defect. Shunt flow through the defect was observed by color Doppler technique, and its velocity was measured using the FFT mode. In two cases, right-to-left shunt blood flow was detected. Two types of probes were used in this study, a lateral scanning probe and a longitudinal scanning probe. The scanning plane of the former was perpendicular to the axis of the probe, and that of the latter was parallel to it. The two probes facilitated the measurement of the two right-angled dimensions, with which we could calculate the defect area, assuming the defect to be an ellipse. The volume of a left-to-right shunt was obtained by multiplying the defect area by the integration of flow velocity against time. Shunt volume per cardiac cycle obtained by this method correlated well with that obtained by the Fick's method during cardiac catheterization. In six cases without a right-to-left shunt, the coefficient of correlation was 0.98, and in all eight cases it was reduced to 0.72. Thus, we concluded that TEE is useful for diagnosing and evaluating ASD.

Adolescent↗
PubMed1990

[Clinical usefulness of transesophageal Doppler echocardiography].

The usefulness of transesophageal Doppler echocardiography (TEE) was assessed in patients with various cardiovascular diseases including 15 patients with dissecting aortic aneurysm (DAA), two with thoracic aneurysm, 16 with ischemic heart disease and 14 with acquired valvular diseases. In dissecting aortic aneurysms, TEE provided clear images of the intimal flaps even in the aortic arch and descending aorta in which clear images could not be obtained by conventional external Doppler echocardiography. The entry site was detected in 11 of the 15 (73%) cases using TEE, but in only three of the 15 cases using conventional Doppler technique. In two cases of true aortic aneurysms, TEE provided clear images of the aneurysm in the descending thoracic aorta, which was discriminated precisely from DAA. In valvular disease, all four valves (aortic, pulmonary and atrio-ventricular valves) were easily observed without disturbance by any other tissues using a transesophageal approach. In addition, valve aneurysms in the posterior mitral leaflets were detected using TEE in two cases. In two cases of mitral stenosis, a thrombus was observed in the left atrial appendage. These findings were confirmed during surgery, but could not be obtained by the conventional external studies. In 16 cases, TEE was performed during aorto-coronary bypass surgery under general anesthesia. In two of these cases, left ventricular assist devices were applied after surgery. In these cases, where conventional Doppler echocardiography was not applicable, cardiac function could be monitored by TEE. Thus, TEE is useful not only in evaluating morphological function in the cardiovascular system but also in monitoring cardiac hemodynamics during and after heart surgery.

Adult↗
PubMed1990

[Pathophysiological analysis of cardiac function by computer processing of echocardiograms].

Automatic image processing system has been developed for analysis of cardiac function with echocardiograms. Echograms of apical long axis view were transferred to microcomputer system and processed to display three dimensional images of left ventricular myocardium. With this technology, analysis of left ventricular wall thickness in three dimensional manner revealed pathophysiological changes in ischemic heart disease.

Coronary Disease↗
PubMed1990

[Computer analysis of echocardiograms].

Owing to its non-invasive nature, echocardiography, is widely used in many fields of clinical sciences. Especially in cardiology, real-time pictures of the beating heart are now essential in clinical practice. With recent developments of computer technology, various aspects of computerization have been introduced into echocardiography. Analysis of cardiac function became easier by automated echocardiography with three dimensional framework, length-tension-velocity. A 3-dimensional view of the heart could also be obtained by computerized image processing of serial echocardiograms. The results of the automated analysis by computer were in good agreement with those with manual measurements. Therefore, the computer processing is valid. These kinds of computer image processing of echocardiograms would be useful in various clinical settings.

Computer Systems↗
PubMed1989

Assessment of transesophageal Doppler echography in dissecting aortic aneurysm.

To assess the clinical value of transesophageal Doppler echography in the diagnosis of dissecting aortic aneurysm, both transesophageal and conventional echograms were performed in 22 cases of dissecting aortic aneurysm. Of the 22 patients, 17 underwent angiography; 8, X-ray computed tomography; 4, both; and 12, surgery. The performance of each method was assessed in the following four segments: A, ascending aorta; B, aortic arch; C, thoracic descending aorta; and D, upper abdominal aorta. The results by angiography were presumed to be correct. In the group of 17 patients who underwent angiography, the rate of correct detection of an intimal flap using the transesophageal approach was 100% in all four segments, significantly better than detection by the conventional approach (segment A, 65%; segment B, 47%; segment C, 35%; segment D, 53%) (p less than 0.01), and the rate of correct detection of the entry sites using the transesophageal approach was 100%, significantly better than that by conventional approach (42%) (p less than 0.05). X-ray computed tomography was not capable of detecting the site of entry in all cases. The presence of thrombus, aortic regurgitation and pericardial hemorrhage were all revealed clearly by the transesophageal approach, and the results were partly proved by other methods. In conclusion, transesophageal Doppler echography provides a rapid and accurate method of diagnosing and evaluating dissecting aortic aneurysm and permits prompt initiation of appropriate treatment.

Adult↗
PubMed1989

[Transesophageal Doppler echocardiography in the diagnosis of dissecting aortic aneurysm].

Transesophageal Doppler echocardiography (TEDE) was performed in three patients with proven or suspected DeBakey type I and type III aortic dissection. Case 1: A 66-year-old woman, with DeBakey type I aortic dissection. Clear images of a widened dissected aorta and an intimal flap were obtained in both the ascending and descending aorta, including the aortic arch. The site of an entry into the false lumen was identified by the defect of the intimal flap and the pulsatile entry flow through it. The reentry into the true lumen was also identified near the orifice of the celiac trunk. In this case, the observation was performed using this technique during the operation; i.e., replacement of the ascending aorta with an artificial graft. Case 2: A 77-year-old man, DeBakey type III aortic dissection. The study was performed after surgery which consisted of replacement of the descending aorta with an artificial graft. TEDE provided clear images of the artificial graft, the aorta, and their boundaries. The remaining intimal flap was clearly confirmed. Case 3: An 80-year-old man, DeBakey type III aortic dissection. In this case, though abdominal echography suggested aortic dissection, angiography and X-ray CT failed to facilitate the diagnosis. Only TEDE confirmed the diagnosis. The abnormal flow via the entry directing toward the false lumen was clearly demonstrated on the color Doppler images. We therefore conclude that TEDE is a useful and reliable means of diagnosing dissecting aortic aneurysm.

Aged↗
PubMed1988

[Left ventricular wall thickness in hypertrophic cardiomyopathy: comparisons of measurements by magnetic resonance imaging, cineangiography, and echocardiography].

To evaluate the usefulness of magnetic resonance imaging (MRI) in measuring regional wall thickness of the left ventricle, 11 patients with hypertrophic cardiomyopathy (HCM) were imaged. The measurements were compared with those obtained by two-dimensional echocardiography (2D-echo) and cineangiography. Regional wall thickness was ascertained at six locations including the base, middle, and apex of the interventricular septum (IVS) and left ventricular posterior wall (LVPW) from the two selected transverse sections. All of these six locations were also measured for the IVS by biventriculography and for the LVPW by left ventriculography with the left anterior oblique view. Only the base was measured for both the IVS and LVPW using 2D-echo because of the difficulty in obtaining good images for the middle and apex of the left ventricle. The measurements by MRI correlated well with those obtained by 2D-echo and cineangiography in the majority of locations. At the base, where the wall thickness was measured by the three methods, the measurements of the IVS correlated well each other (r = 0.63 to 0.81). However, a good correlation was obtained only between 2D-echo and MRI for the LVPW r = 0.75. The correlation between MRI and cineangiography was generally good for the IVS at any levels (r = 0.76 to 0.87), but not for the LVPW. This was partially due to the narrow range of data for the LVPW as well as to the difficulty in determining the epicardial border in left ventriculograms. In conclusion, regional wall thickness can be correctly measured by MRI in any locations of the left ventricle even at the apex, where measurement is difficult by other methods.

Adolescent↗
PubMed1986

Detection and evaluation of tricuspid regurgitation using a real-time, two-dimensional, color-coded, Doppler flow imaging system: comparison with contrast two-dimensional echocardiography and right ventriculography.

To detect and evaluate regurgitant flow in tricuspid regurgitation (TR) with a newly developed, realtime, 2-dimensional (2-D), color-coded, Doppler flow imaging system (Doppler 2-D echo), 27 patients (18 with suspected TR and 9 normal subjects) were examined and the findings were compared with those obtained using contrast 2-D echocardiography (contrast 2-D echo) and right ventriculography. In 16 of 18 patients with suspected TR, Doppler 2-D echo easily visualized the color-coded regurgitant flow in the right atrium and estimated the severity of TR from the distance of the visible TR jet. On the basis of the QRS synchronized appearance of contrast in the inferior vena cava by the subxiphoid approach or of the negative contrast effect above the tricuspid valve just after the contrast entered the right ventricle with its subsequent back-and-forth movements across the tricuspid valve, Doppler 2-D echo was more sensitive and specific in detecting TR (100% and 100%) than contrast 2-D echo (75% and 82% in the subxiphoid view, 56% and 100% in the 4-chamber view) when the fast Fourier transformation frequency analysis was used as the standard of TR, and it was more sensitive in detecting TR (85%) than contrast 2-D echo (69% in the subxiphoid approach, 46% in the 4-chamber view) when right ventriculography was used as the standard of TR. Additionally, the severity of TR as shown by Doppler 2-D echo correlated fairly well with that shown by right ventriculography. Thus, Doppler 2-D echo is clinically useful for detecting and evaluating TR.

Adult↗
PubMed1986

Dynamic changes in left ventricular regional wall thickness during premature ventricular contraction in conscious dogs.

The contractile pattern of the regional left ventricular wall during premature ventricular contraction was analyzed in conscious dogs instrumented with an ultrasonic dimension gauge across the anterior and posterior left ventricular walls. Aortic flow was measured with an electromagnetic flow probe. A single premature ventricular contraction was induced by stimulating either the anterior or posterior wall with varied coupling intervals from 380 to 650 msec. Stroke volume of premature ventricular contraction was significantly smaller than that of premature atrial contraction with identical coupling intervals. In premature contractions, stroke volume was linearly related to coupling intervals. Though there was no isovolumic wall thickening in premature atrial contraction, the wall started to thicken during isovolumic ventricular systole in premature ventricular contraction. There was a clear inverse correlation between the ratio of the isovolumic wall thickening to the total wall thickening and coupling intervals. In premature ventricular contractions with identical coupling intervals, the deformation of thickening characteristics was more pronounced in regions with closer proximity to the ectopic focus. Thus it is concluded that the pump function is depressed in premature ventricular contraction, in part due to the increased ratio of wall thickening during isovolumic systole before the opening of the aortic valve. Isovolumic wall thickening increases along with the shorter coupling intervals and closer proximity to the ectopic focus. These alterations in left ventricular mechanical function due to ectopic contraction might induce serious sequelae, depending upon the ectopic focus in the presence of already depressed regional function.

Animals↗
PubMed1985

Detection of intracardiac shunt flow in atrial septal defect using a real-time two-dimensional color-coded Doppler flow imaging system and comparison with contrast two-dimensional echocardiography.

To evaluate the noninvasive detection of shunt flow using a newly developed real-time 2-dimensional color-coded Doppler flow imaging system (D-2DE), 20 patients were examined, including 10 with secundum atrial septal defect (ASD) and 10 control subjects. These results were compared with contrast 2-dimensional echocardiography (C-2DE). Doppler 2DE displayed the blood flow toward the transducer as red and the blood flow away from the transducer as blue in 8 shades, each shade adding green according to the degree of variance in Doppler frequency. In the patients with ASD, D-2DE clearly visualized left-to-right shunt flow in 7 of 10 patients. In 5 of these 7 patients, C-2DE showed a negative contrast effect in the same area of the right atrium. Thus, D-2DE increased the sensitivity over C-2DE for detecting left-to-right shunt flow (from 50% to 70%). However, the specificity was slightly less in D-2DE (90%) than C-2DE (100%). Doppler 2DE could not visualize right-to-left shunt flow in all patients with ASD, though C-2DE showed a positive contrast effect in the left-sided heart in 9 of 10 patients with ASD. Thus, D-2DE is clinically useful for detecting left-to-right shunt flow in patients with ASD.

Adolescent↗
PubMed1985

Nonuniformity of inner and outer systolic wall thickening in conscious dogs.

Transmural differences in systolic wall thickening were analyzed in 13 conscious dogs by implanting sonomicrometers to continuously measure total wall thickness (WT) and outer WT approximately half the distance through the myocardium at a closely adjacent location. Inner WT was derived by subtraction of outer WT from total WT. Outer wall measurements spanned, on average, the outer 44 +/- 10% (+/- SD) of the wall; derived inner wall measurements spanned the remaining 56 +/- 10%. At rest the fractional contribution (FC) of the outer wall to total systolic wall thickening was 29 +/- 9%, which was significantly less than the FC of the inner wall, 71 +/- 9%. These data are in good agreement with simplified modeling of a cross section of the left ventricle as two concentric rings that predicts that the FC of inner and outer halves of the wall should be approximately 67 and 33%, respectively. During treadmill exercise, the extent of both inner and outer thickening increased significantly (30 and 29%, respectively) but the relative FC of the inner and outer wall remained the same. The data indicate that systolic wall thickening is nonuniform and that this nonuniformity remains constant during the increased inotropic and chronotropic stimulation associated with exercise.

Animals↗
PubMed1985

[Determination of left ventricular center of contractile motion by two-dimensional echocardiography].

To quantify left ventricular (LV) regional wall motion using two-dimensional echocardiography, reference points such as the center of left ventricular gravity or an intersecting point of radial grids were conventionally used, assuming that they were near or at the center of LV contractile motion. However, since the LV does not contract homogeneously, their positions might be quite different. Endocardial high density spots in two-dimensional echocardiograms were used as markers for LV regional wall motion, and we determined the center of LV contractile motion (C) at papillary muscle level in the parasternal short-axis view for 10 normal subjects (control group) and eight patients with aortic regurgitation (left ventricular volume overload; LVVO group). In one subject, each of six endocardial high density spots extracted from different LV regions, and were traced frame by frame throughout one cardiac cycle using a video motion analyzer, and their systolic movements were shown by six vectors. Using the method of least squares, the point of convergence of vectors (C) was determined from the point toward which the six vectors were directed. The LV centers of gravity at end-diastole (Ged) and at end-systole (Ges) were also determined by tracing the endocardial surface on video frames. The distributions of C, Ges, and Ged were compared. In the control group, point C was at the point 35% distant from Ged toward the middle of the interventricular septum (IVS). Ges deviated from Ged in the same direction as point C, but the distance was one third of C(11%). In the LVVO group, the distribution of Ges referred to Ged was similar to that of the control group, however, point C was closer to Ged, since its deviation was 16% of the radius. These results suggest that point C, which is determined by the directions of regional wall motion, reflects the contractile pattern of the whole LV. This might be termed the center of LV contraction. Using it as a reference, we were able to obtain more accurate quantitative data about LV regional wall motion.

Aortic Valve Insufficiency↗
PubMed1984

Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: comparison with two-dimensional echocardiography.

The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 +/- 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 +/- 0.20 and 0.98 +/- 0.11, respectively; p less than 0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 +/- 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 +/- 0.38 and 1.04 +/- 0.09, respectively; p less than 0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC.

Adult↗
PubMed1984

Progression from hypertrophic obstructive cardiomyopathy to typical dilated cardiomyopathy-like features in the end stage.

An autopsied patient who had shown typical dilated cardiomyopathy (DCM)-like feature in the end stage of familial obstructive hypertrophic cardiomyopathy (HCM) is presented. The patient, a 38-year-old male, had 2 sisters with HCM. Six years before death, the echocardiogram revealed marked asymmetric septal hypertrophy (ASH) with systolic anterior motion (SAM). The ventricular septum (VS) to left ventricular posterior wall (LVPW) ratio was 19 mm/10 mm and LVEDd was 47 mm. Subsequently, the signs and symptoms of congestive heart failure became progressively worse and DCM-like findings appeared insidiously. Two months before death, the echocardiogram revealed LV dilatation (LVEDd = 55 mm) with diffuse poor contraction, no ASH (VS/LVPW = 7 mm/9 mm) and no SAM. At autopsy, the heart weighed 480g and showed dilated LV hypertrophy with normal wall thickness (VS/LVPW = 9 mm/13 mm). Massive fibrosis (30% in the VS), diffuse disarray (18% in the VS) and severe narrowing of the intramural small arteries and arterioles were found in the middle and outer thirds of the VS and the anterior LV wall. The extramural coronary arteries were not stenosed. The insidious progression from HCM to typical DCM-like feature related to the chronic progression of necrosis and massive fibrosis, due to severe stenosis of the intramural coronary artery. The data indicate that patients diagnosed clinically as DCM may be HCM, especially in those with family history of HCM.

Adult↗
PubMed1984

Improvement of pacing induced regional myocardial ischemia by Solcoseryl in conscious dogs with coronary stenosis.

The effects of Solcoseryl on regional myocardial function were studied in 5 conscious dogs with partial coronary constriction, in which temporary ischemia was induced by rapid cardiac pacing. During the coronary artery constriction, the percent shortening of the ischemic segment decreased by 9%. When the heart rate was increased by pacing, the percent shortening of the ischemic segments was further reduced by 57%. On cessation of cardiac pacing, the early potentiation of dP/dt and of control segment shortening became evident and was followed by exponential decay in the subsequent several beats. In the ischemic segment, the percent shortening was significantly improved in the first post-pacing beat but was more severely depressed at five seconds. Thirty minutes after administration of Solcoseryl, the cardiac pacing was repeated in the same manner but the pacing-induced hypokinesia of the ischemic segment were less marked, the percent shortening being at an average of 9.1% during control pacing and 12.7% during the second pacing after Solcoseryl (p less than 0.05). Postpacing deterioration of the ischemic segment shortening was also significantly improved from 9.8 to 11.8% at 5 seconds (p less than 0.05). These findings indicate that Solcoseryl exerts protective effects on the ischemic myocardium by promoting a rapid recovery from ischemia, probably due to the improvement of oxygen utility through activated cellular respiration.

Actihaemyl↗