Abstract: This report describes a procedure of automatic control of perfusion
flow and blood pressure during cardiopulmonary bypass. The control system,consisting
of a proportional-integral feedback regulator and a set-point adjuster
based on production rules,automatically regulates both arterial infusion
and venous withdrawal pumps throughout cardiopulmonary bypass. The proportional-integral
regulator maintains central venous pressure to keep the intravascular volume
constant. The set-point adjuster modefies the target values of central
venous pressure and perfusion flow rate by monitoring the response of central
venous pressure,blood volume in a reservoir, and the collapse of a small
vinyl bag in a venous withdrawal line. We studied the ability of this control
system during cardiac operation on eleven patients and compared it with
an earlier computerized cardiopulmonary bypass without a set-point modifications
were reduced from 7.6 ± 5.3 times to 3.9 ± 3.2 times .The set-point adjuster
, therefore, improved the response of the proportional-integral regulator
.
Key words : Automatic control , Cardiopulmonary bypass, Computer control,Production
rules,Proportional-integral control.
Abstract: A surgical case of a basilar aneurysm which is navigated by computer-assisted
geometric design is described. The concepts and technical details of computer-assisted
geometric design of cerebral aneurysms was reported in our previous paper.
Computer graphic transformations including shifting , scaling , rotation
,and applying different colors in different intensities make it possible
to obtain surgical simulation of a basilar aneurysm and its dynamic morphology.
An illustrative case is described,and problems and innovations for computer-assisted
surgical design are descussed.
Key words: Basilar aneurysm,Navigation, Surgical simulation, Three-dimensional
imaging.
INTRODUCTION
Nowadays, voxel (volume cell) data of living human body can be obtained
by X-ray CAT ,Medical Resonance Imaging (MRI) and ultrasonic imaging.
And 3-D positioning and understanding of 3-D shape of bone and / or soft
tissue are strongly required by using voxel data.
As one of the requests,3-D picture display by the method of Holographic
Stereogram (HS) has been developed.
Here,first the principle of holography and HS is explained,shortly.Then
, the application to medical pictorial data is shown.
INTRODUCTION
Holographic display is now popular in JAPAN, but,it is general to use a
fluorescent lamp as hologram illumination source. This leads serious image
blur and ,thus decreases the visual effects of hologram. This weak point
is a serious problem when the hologram is used for business promotion,the
image blur losses the eye-catching and spoils the main reature of rainbow
hologram . For these reasons ,a new type of holographic display is considered
to improve the problems as mentioned above and enhance the visual effects.
In practice,we considered an idea to use a simplegrating as a image pixel,
then an image is assembled from the grating,dots. From the feature of the
novel recording method,we called it a "Grating Plot Method",and
named the image which consists simple grating dots as a "Grating Image".Now
,grating image has about 20% in market field of the general rainbow hologram,
and is continuouwly growing up in holographic display field. And ,we improve
this technology to realize 3D image and 3D video system as follows.
Absuract: A new system based on the integral photography, named '3D Plotter'
,has been developped which records and visualizes three-dimentional internal
organ objects for localization in surgical support. The recorded media
are compact and portable enough to use in daily clinical use .A simple
half-mirror based image overlay system was also constructed . In this paper
,recording principle and the specified data processing methods of our system
is described.
INTRODUCTION
Most of the current 3-D display use the effect of binocular disparty by
presenting different images for both eyes,what is powerful and the easiest
way for realizing virtual 3-D world. However, this approach has following
drawbacks.
(1)The convergenve angle and the focusing control of our eyes are unbalanced
in this type of display ,which makes a user feel a severe eye fatigue.
(2)The display can not provide a real-time auto-stereoscopic image,namely,motion
parallax,which is a very important cue for a user to recognize the extent
of the 3-D spase.
Therefore,the authors employ a defferent method called volume scanning
to develop a 3-D display which can overcome these defects .Although the
image quality of this type of displays is not as good as that in the binocular
stereoscopic displays it is created in real 3-D space and can be viewed
from any points. The experimental system has already been developed and
applied to interactive voxel-vased shape modeling .The system presented
here is almost the same as the experimentai one, but it intends to be used
i a more practical situation .
In the following sections,the principle,the configuration and the image
manipulation tools of the volume scanning display system are described.
Absutract: Stereoscopic,multi-parallax,electro-holographic and multi-planer
methods are no glasses methods as real-time 3-D imaging devices.These methods
except stereoscopic need several parallax images or several plane images
for their 3-D image component.It is known there are many problems for taking
and transmission of their 3-D images. As for stereoscopic method using
lenticular sheet limits the position of the viwers and /or is impossible
to observe the 3-D image by several persons simultaneausly. Our spatial-multiplexing
method Stereoscopic Liquid Crystal TV does not have such above drawbacks.