Masao Yokota

A method to estimate cardiac volume by two-dimensional echocardiograms recorded from one extracorporeal point

This paper presents a method for estimating the volume of a cardiac region from its oblique sectional images recorded with a sector scanner. The probe of the scanner is attached to the chest wall and an ultrasonic beam is cast from a fixed intercostal space. In a previous paper a method of calculation for the above recording technique was reported. The present method is superior to the previous one because it minimizes calculation error and is applicable to organs of intricate shape.

A Method to Estimate Volume and Surface Area of Organ by Two-Dimensional Echocardiography

Two-dimensional echocardiography has recently facilitated production of cardiac sectional images. This paper describes a method to estimate volumes and surface areas of various cardiac regions from their oblique sectional images. Cardiac oblique sectional images are recorded with a sector scanner probe which is tilted gradually on an intercostal point. The contour of a particular region on the recorded image is traced manually to put into a computer. The computer calculates the volume and the surface area using a triangular pyramid as the fundamental segment. The accuracy on this calculation method was evaluated by two types of phantoms constructed in the computer. The method is applicable to determine the volume and the surface area not only of the heart, but also of other organs even though they have indents or protrusions on the surface.

Knowledge-based picture understanding of weather charts

Abstract This paper describes a knowledge-based weather chart understanding system named WERP, which is working as a picture processing part of our Information understanding System Of BAsic weather Report (ISOBAR). WERP is designed to extract necessary information from a weather chart for generating weather report sentences explaining the chart. This system is based on a structural model of the weather charts. Here, we study what problems are involved in weather chart understanding, how they are solved and how an actual system is organized. Also, picture-processing techniques for weather chart processing and some experimental studies are considered.

Language-Picture Question-Answering Through Common Semantic Representation And its Application to the World of Weather Report

This paper presents some methodologies for constructing systems which can understand both natural languages and pictorial patterns, and describes an application system of the weather report world.

A method for volume estimation by two-dimensional echocardiography: examination with excised animal left ventricles.

Applicability of a newly developed volume estimation method was examined with excised left ventricles of pigs and dogs. Serial oblique-sectional images of a left ventricle were recorded with a two-dimensional echocardiograph. The probe of the echocardiograph was fixed at one point and was tilted stepwise. Contours of the left ventricle in the images were traced to put into a computer and volume was calculated. Calculated volume of 19 left ventricles agreed well with true volume in wide range (r = 0.982 for left ventricular myocardium and r = 0.989 for left ventricular cavity).

A computer program for detection of segmental contraction abnormalities by the left ventricular cineangiogram

A computer program which enables detection of segmental abnormalities of the left ventricular contraction was developed using the principles of Leighton et al. [Circulation 50 (1974) 121-127]. A film projector, a digitizer, a graphic display and a mini-computer are used. The end-diastolic (ED) and end-systolic (ES) left ventricular silhouettes are traced from 30 degrees right anterior oblique cineangiograms projected on a screen of the film projector. The program determines semi-automatically both apexes and longitudinal axes of the left ventricle. Lines [(N-1) less than or equal to 60] are drawn perpendicular to longitudinal axes, dividing longitudinal axes into equal N segments, respectively. These perpendicular lines are extended to intersect ED and ES silhouettes at 2(N-1) points, respectively. The distances along each of 2(N-1) hemiaxes are defined as short axes [S-EDi and S-ESi, i = 1-2(N-1)]. Segmental wall contractions are expressed as a percentage of the distance from S-EDi to S-ESi, and displayed as a graph with normal values (mean +/- 2 SD). The presence and extent of segmental contraction abnormalities can be evaluated quantitatively by observing a percentage of segmental wall contractions. This program greatly facilitates a correct diagnosis in clinical use.

A beat-to-beat calculator for the diastolic pressure time index and the tension time index

We have developed a beat-to-beat calculator which can calculate in real-time the ratio of the diastolic pressure time index (DPTI), and the tension time index (TTI) as an index of the myocardial oxygen supply/demand balance. Physicians set up presumed value for the left ventricular endodiastolic pressure, a search area for the dicrotic notch, a threshold for the onset of the up-slope and the corresponding value of the calibration signal on the digital switches of the calculator. Next, the arterial pressure analog signal is input into the calculator. The calculator searches automatically for both the onset of the up-slope and the dicrotic notch. The arterial pressure curve is displayed beat-to-beat with the recognized onset and the dicrotic notch on the CRT to be confirmed by physicians. When physicians do not agree with the automatic recognition they can fit the automatic recognition to the observation. If the recognition of the onset is inadequate, the threshold can be re-adjusted to trigger the onset. If recognition of the dicrotic notch is inadequate, the physician can adjust the search-area. Therefore, physicians who operate the calculator can rely on the calculated DPTI/TTI. This calculator can continuously monitor the myocardial oxygen supply/demand balance in patients with acute myocardial infarction or just after open-heart surgery.

An electrocardiogram database incorporated into the hospital information system

A database system was developed for storing and retrieving electrocardiogram (ECG) interpretations made by the Bonner program. One ECG record consists of the patient identification information, measurement matrix, and interpretive statements made by the program and by the reviewing cardiologist. The logical structure of the database is 3-level hierarchy. An ECG record is automatically inserted into the database when an ECG signal is analysed by the program. Stored ECG records can easily be retrieved using any parameter and qualifier for review, research and education. The physician can gather statistics on the parameters and qualifiers of the extracted ECG records using statistical program packages (BDMP, SCSS) and a decision support system (AS). Since the database management system is DL/I, the newly developed system can be transferred to various computers, and the relationships between the ECG findings and clinical records stored in the DL/I form can easily be studied.

An on-line system for electrocardiogram interpretation using the bonner program

An on-line system for electrocardiogram (ECG) interpretation using the Bonner program has been developed. The system consists of a telephone network, a process computer, a host computer, a computer interface and an electrocardiograph equipped with transmitting options. The signal acquisition program offered by IBM was modified so as to be equipped with the following functions: The technician can distinguish whether the process computer is ready or not, even if he is working in an examination room which is distant from the computer room. The data received by the process computer is transferred to the host computer in real time. In cases where the host computer is unable to receive the data, the process computer restarts transmission quickly after the host computer recovers the function of receiving. The host computer interprets transferred data in real-time by the Bonner program. The interpretation report is printed in real time on a remote printer. As the result of these modifications, a series of data processing operations may be executed without intermediary operators. The printed interpretation report begins to appear about ten seconds after completion of transmission.

Computer Analysis of Left Ventricular Pressure-Volume Relationships by Echocardiography

Programs were developed for the analysis of left ventricular pressure-volume relationships in clinical situations. Regression lines of end-systolic points on the pressure-volume plane were obtained from nine patients. Correlation coefficients between end-systolic pressure and volume were high. The indices calculated may be useful for diagnosis and research of left ventricular function.