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Biomedical subjects

H Inagaki

Publications and source records attributed to H Inagaki.

At least 181 records · Page 10Linked to original sources
PubMed1984

A computational aspect of kinetic depth effect.

A method is proposed to determine the rigid structure as well as the three dimensional motion of an object from a sequence of orthographically projected images. It is assumed that the velocities as well as the positions of the points attached to the object are observable in the images. The "instantaneous rigidity condition" wich states that the relative position vector between any two points is orthogonal to the corresponding relative velocity vector is derived from the condition of rigidity. Assuming further that the rotational velocity component is constant throughout the period of observation, each of the projected relative velocity vectors is shown to move along one of the elliptical trajectories, all of which are similar to one another. The orientations of the longer axes are common to every trajectory. Then one can determine the equations of the ellipses by observing only two points in three views or three points in two views. The solution is obtained from a set of linear equations. The length of the longer axis enables one to determine the relative velocity. The instantaneous rigidity condition is then used to obtain the relative position. The special cases where the rotational axis is either perpendicular to or parallel with the image plane are discussed. The above results are discussed in relation to the relevant psychophysical observations as well as theoretical studies.

Depth Perception↗
PubMed1983

Postnatal development of circadian rhythm in serum cortisol levels in children.

High-pressure liquid chromatography was used to study the development of blood adrenocortical circadian rhythm in a total of 64 children, ranging in age from 1 month to 15 years. Patients with endocrine diseases, congenital anomalies, and diseases of the central nervous system were excluded from this study. Determination of corticosteroid concentration was possible with 20 to 100 microL of serum. Twenty-four hour patterns were determined at six-hour intervals. A distinct circadian rhythm with an amplitude comparable to that of an adult emerged at approximately 6 months of age.

Adolescent↗
PubMed1982

Correlative studies between Frank vectorcardiograms and thallium-201 myocardial perfusion images in patients with old anterior myocardial infarction.

A correlative study was performed on 70 patients with old anterior myocardial infarction between each of the orthogonal components of instantaneous QRS vectors and the anterior-wall, lateral-wall and septal myocardial uptake ratios (A-MUR, L-MUR, and S-MUR, respectively). These MURs were calculated from the thallium-201 myocardial perfusion images at 5 projections and used as the index of the infarct size of the respective LV wall. The Z components of the 14-msec and 24-msec instantaneous QRS vectors significantly correlated with the S-MUR (r = -0.51) and the A-MUR (r = -0.66) respectively. The X component of the 32-msec instantaneous QRS vector also showed a significant correlation with the L-MUR (r = 0.59). The regression equations obtained in the present study seemed also applicable to patients with complete right bundle branch block. It is concluded that the quantitative analysis of the Frank vectorcardiograms could afford valuable information as to the size as well as the site of myocardial infarctions.

Adult↗
PubMed1981

The quantitative diagnosis of thallium-201 myocardial perfusion images and vectorcardiograms in myocardial infarction and hypertrophic cardiomyopathy.

Correlation studies were carried out between thallium-201 myocardial perfusion images and vectorcardiograms in 77 patients with myocardial infarction (48 anterior and 29 inferior infarctions) and 30 patients with hypertrophic cardiomyopathy. A quantitative method was developed; myocardial 201Tl uptake index (a relative myocardial activity to background, MUI) and myocardial 201Tl uptake ratio (a ratio of regional myocardial counts to maximal myocardial counts, MUR) were utilized to differentiate myocardial infarction from hypertrophic cardiomyopathy, and evaluate them. A fairly good agreement between left ventriculograms and myocardial perfusion images was obtained in myocardial infarction (diagnostic accuracy 95.1% in anterior and 75.6% in inferior infarction). In anterior infarction the linear relationship of r = -0.58 (p < 0.001) was obtained between asynergy index and mean anterior MUR. A highly significant correlation was observed between anterior MUR and the instantaneous 24 msec Z component (r = -0.80, p < 0.001). In inferior infarction, Qy/Ry was correlated to inferior MUR (r = -0.58, p < 0.001). In hypertrophic cardiomyopathy, four types of hypertrophic sites were classified with 201Tl images (septal, apical and anterior, apical and septal, and anterior dominant types). Azimuth angles of instantaneous 10 msec vector were directed right-anteriorly (mean 114.5 degrees) in septal hypertrophy, and left-anteriorly (mean 84.9 degrees) in apical and anterior hypertrophy. Elevation angle of maximal T vector in apical hypertrophy was deviated superiorly (mean 102.6 degrees). There was a good correlation (r = 0.60, p < 0.001) between the magnitude of spatial maximal QRS vector and lateral wall MUR.

Adolescent↗
PubMed1980

Diagnostic value of body surface map in myocardial infarction: assessment of location, size and ejection fraction as compared with coronary cineangiography and 201Tl myocardial scintigraphy.

The diagnosis of the location and size of old myocardial infarction was made by the map and various indices obtained from the map were correlated with coronary arteriography, left ventriculography, and 201Tl myocardial scintigraphy. Diseased coronary arteries were presumed from Q30, Q40 area and/or peak voltage map and left ventricular wall motion was estimated from subtraction map. There were significant correlations between ejection fraction and sigma R in anterolateral MI (r = 0.51, p less than 0.001) and between ejection fraction and nQ30 in anterolateral (r = -0.47, p less than 0.001) and inferoposterior (r = -0.63, p less than 0.01) MI. Negative correlation was observed between myocardial uptake ratio (MUR) and nQ30 (r = -0.69, p less than 0.001) and positive correlation between MUR and sigma R (r = 0.50 p less than 0.01) in anterolateral MI. Those cases which could not be diagnosed by either ECG or 201Tl scintigraphy were correctly diagnosed by the map and it proved to have an excellent diagnostic accuracy for myocardial infarction.

Adult↗