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International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 5. Hakodate 1998
THE FRONTAL 3-D IMAGING FOR PTCA USING A RING ARRAY PROBE
Masayuki Nambu, Ayumu Matani, Osamu Oshiro, Kunihiro Chihara
Grad. School of Information Science
Nara Institute of Science and Technology
8916-5, Takayama, lkoma, Nara, 630-0101
E-mail: (masayu-n,matani,oshiro,chihara Gis.aist-nara.ac.jp
JAPAN
Commission V, Working Group V/4
KEY WORDS: ultrasound, 3-D imaging, PTCA, ring array probe
ABSTRACT
PTCA (Percutaneous Transluminal Coronary Angioplasty) is the most popular treatment for arteriosclerosis. In the
operation by PTCA, to measure the size of a lesion quickly and accurately is very important. However, there is
not any effective method to measure. Then we have proposed a method to measure the size of a lesion. This
measurement method is called "the Instantaneous Frontal Imaging Method”. We propose a new algorithm for the
Instantaneous Frontal Imaging Method. In a conventional method, ultrasound is supposed to be reflected to a fixed
direction corresponding to the normal of the reflector's surface. In the new algorithm, we set the model of reflection
of the ultrasound that the ultrasound is reflected to the fixed direction at whole points of measurement domain. Inner
products of measured and the calculated signals show the probability of reflector's existence at a point. In addition,
we can reconstruct the 3-D image of reflector to display this probability. To use this new algorithm, we can obtain
an image with high S/N ratio in the short time.
2 -——
1 Introduction S
alloon catheter
The arteriosclerosis is one of important adult's dis-
eases, and the main cause of myocardial infarction. In
the arteriosclerosis, the cholesterol composed to the
inside wall of the blood vessel, and the blood flow
is interfered. When a stricture closes the blood vessel
completely, the heart will necrotize, because the blood
stops flowing into the heart. In the treatment of the
arteriosclerosis, the PTCA (Percutaneous Translumi-
nal Coronary Angioplasty) is usually performed. If
this method is used, it is not necessary that the dan-
gerous operation to open the chest of the patient.
: à
N d a,
b blood vessel
3
4
blood ===
Ar
balloon
Figure 1: PTCA
we had developed the special ultrasonic probe which
is called the ring array probe as shown in figure 3 and
4, and we have researched the measurement method
called ”the Instantaneous Frontal Imaging Method”
[1],[2] and image reconstruction algorithms using this
ultrasonic probe. We propose the new image recon-
struction method using this ultrasonic probe.
The procedure of PTCA is shown in figure 1. First,
the catheter is inserted to the blood bessel. Next, the
guide wire which is mounted on the catheter pierces
the stricture. Subsequently, the balloon which is also
mounted on the catheter is inserted the hole which
is opened by the guide wire. The balloon is expanded
and crushes the stricture. Final, the blood flows smoothly c
again. 2 Ring Array Probe
However, if the guide wire or the blood vessel is bent
as shown in figure 2, the guide wire will pierce the
blood vessel, and the operator must open the chest of
patient urgently. The operator must know the size of
a lesion or three dimensional structure of stricture and
blood vessel.
This ultrasonic probe has some ultrasonic transduc-
ers that are located circularly. The one transducer
transmits the spherical pulsed ultrasound, and that
is different from traditional ultrasonic measurement
method which transmit the ultrasonic beam. The ul-
trasound is reflected by the object in the measurement
region, and is recieved by all trancducers of the probe.
However there is not any effective method to measure The flight times of the ultrasounds are different each
the size of a lesion or three dimensional structure of ^ transducers. Therefore, we can recognize the position
stricture and blood vessel in the operation. Therefore, of the object from these differences. The specification
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