Turbulence velocity has been measured in the canine ascending aorta using a hot-film anemometer. An experimental setup capable of producing a wide range of cardiac output as well as heart rate in the normal cardiac contractile state was used. Blood flow velocity was measured at various points across the ascending aorta approximately 1.5 to 2 times the diameter downstream from the aortic valve.
Turbulence spectrum (normalized energy density function E (k) ) was calculated from the blood flow velocity data by the fast Fourier transform technique. Characteristics of the turbulence spectrum were examined in connection with the mean Reynolds number and/or measuring positions.
Results :
1) In the higher wave number range, the values of the turbulence spectra are higher at larger mean Reynolds number. There is a wide range of wave numbers for which the spectrum slope is-5/3, when the mean Reynolds number is large. This suggests the existence of inertial subrange.
2) In the higher wave number range, the values of the turbulence spectra are higher at points closer to the centerline of the aorta, when the mean Reynolds number is relatively large.
3) The patterns of the turbulence spectra at various points outside the boundary layer on the aortic wall are similar. In the ascending aorta, the range of the effect of the wall on turbulence seems to be limited to its vicinity.

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Computed tomography, equipment provides cross sectional images of human bodies. From these two-dimensional images, doctors can extract useful information for diagnosis.
Possibilities of contour extraction and three-dimensional construction of objective regions of affected parts (dilated ventricles) have been investigated on the basis of brain CT' images.
The perspectives of extracted three-dimensional objects are dynamically displayed on a three-dimensional graphic display system and following conclusions have been obtained.
(1) Three-dimensional images provide helpful information for recognizing the shapes of objective regions of affected parts of a brain.
(2) The volume and cross sectional area of the object of interest are available from this system.
Especially the volumetric ratio of dilated ventricles to cranium has the possibility of becoming a better measure than the conventional one.

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The epicardial mapping, which draws the conduction equi-time lines based on the measured epicardial potentials, is useful for the intraoperative diagnosis in ventricular arrhythmia, WPW syndrome and surgical conduction disturbances. However, since the present mapping procedures are processed by manual operation, it takes many minutes and moreover requires a great deal of trouble, disturbing the surgical operation.
A newly developed epicardial mapping system is described in this paper. This system is mainly designed for the intraoperative use, and has the following features :
(1) Display of the epicardial map is processed on line in parallel with the measurement of epicardial potentials so that the operator could observe the process of the mapping. The mapping also is almost completed at the end of the measurements.
(2) The conduction equi-time lines are drawn in color at every 5 or 10 msec interval. The earliest excitation portion is displayed red and blue so that the epicardial conduction pattern could be recognized at a glance.
(3) The use of a microcomputer makes the system size smaller so that the equipment can be carried into the operating room. The description of the system as well as the results of testing the system with dog experiments are presented.

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The arrival time and position of the activation front on the right ventricular epicardium are important information for diagnosing the site and degree of, right bundle branch block in detail. However, the smoothing of the current field within the torso results in the attenuation of the high spatial frequency components of the epicardial potential field transmitted to the body surface. Consequently, the appearance time of epicardial breakthrough obtained by inspection of body surface maps always shows a time lag of a few milliseconds. In this study, a new method has been developed to reduce this time lag. Using this new method, the appearance time of the epicardial breakthrough was obtained from the body surface by means of a 2-dimensional laplacian filter for enhancement of high spatial frequency components of the body surface potential field.
Body surface isopotential maps incorporating the characteristic patterns reflecting the epicardial breakthrough were recorded on 17 normal healthy persons using a 9×9 electrode array with an inter-electrode distance of 1. 25 cm. The results obtained by the new method and the body surface map inspection method were compared. Subsequently, simultaneous recordings of the body and epicardial surface isopotential maps were performed on 3 dogs using a 9×9 electrode array with an inter-electrode distance of 1. 5 cm for the body surface mapping and 43 electrodes for the epicardial mapping. In order to evaluate the accuracy of the new method, the values obtained were compared with the appearance times of the activation front breakthrough on the epicardial surface.
In conclusion, the appearance time Of breakthrough determined by the new filter method from the body surface was much earlier than that by the usual inspection method in human cases. The time delay with the new filter method was not significantly different from the appearance time of activation front breakthrough on the epicardial surface in dogs.

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[in Japanese]

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