Ultrasonic probe having means for receiving a puncturing cannula therethrough

An ultrasonic probe having structure for receiving a puncturing cannula therethrough, the probe including a substantially rectangular parallelepiped-shaped support member, the height of the member being relatively much less than the length and width, a plurality of ultrasonic transducer elements arranged in at least one row closely adjacent to one edge of the bottom surface of the support member, cable structure for individually connecting said transducer elements to an external processing unit, and a slot for guiding the puncturing cannula, the slot opening into a first face of the parallelepiped-shaped member perpendicular to the bottom surface and adjoining said row of transducer elements, and said slot being centrally positioned relative to the row of transducer elements. Preferably the depth of the slot is only slightly greater than the diameter of the cannula and the width of the slot permits substantially no lateral movement of the cannula parallel to the row.

BACKGROUND OF THE INVENTION 
This invention relates to an ultrasonic probe for use with a puncturing 
cannula and, more particularly, to an ultrasonic probe having a slot for 
guiding a puncturing cannula therethrough. 
When withdrawing tissue or body fluids from organs in a human body such as 
liver or kidneys by a suitable puncturing cannula for diagnosis, it has 
been known to use an ultrasonic probe for guiding the cannula so as to 
perform a safe puncture by simultaneously observing on a display the 
objective of the operation, and the movement of the cannula in the body. 
Shown in FIG. 1 is a conventional ultrasonic probe having means for 
receiving a puncturing cannula. The probe includes a substantially 
rectangular parallelepiped-shaped support member 1 provided with a 
plurality of ultrasonic transducer elements 2 arranged in at least one row 
on its bottom surface 1a which will be in contact with the human body. The 
transducer elements 2 are individually connected to a display (not shown) 
by a cable 3, as shown in FIG. 1, for showing tomographs of the organ to 
be contracted and the advancing cannula. The support member 1 is provided 
with a guide slot 4 extending through the support member 1 from the top 
surface 1b to the bottom surface 1a. The slot 4 narrows from the top 
surface 1b to the bottom surface 1a for guiding a cannula to position 
substantially at the midpoint of the row of transducer elements 2. The 
height of the member 1 between the surfaces 1a and 1b is normally greater 
than the width of the surface 1a, from front to back as shown. 
An elongated aperture 5 communicating with the guide slot 4 is defined on a 
side face of the member 1 intersecting rectangularly with the bottom 
surface 1a and upper surface 1b of the support member 1. By this 
arrangement, when performing X-ray photography, after the cannula has 
punctured the objective of the subject, the support member 1 can be 
removed by a lateral movement on the body surface of the subject without 
disturbing the cannula. 
Moreover, the conventional ultrasonic probe is constructed for use on the 
surface of the body and for use with a relatively long cannula. It has 
been found that in the conventional probe the cannula is unstable and 
difficult to direct with accuracy. 
In recent years, the conventional ultrasonic probe has been used internally 
in examinations to identify, for example, metastasis of cancer of the 
liver. In these examinations, an incision is made in the abdomen and the 
probe is inserted into the abdomen and into actual contact with the liver 
and other organs which may be affected. In order to secure the proper 
alignment of the row of transducer elements 2 on the bottom surface 1a of 
the probe, a portion of the probe often must be inserted between the 
costae (ribs) and the liver or other organs. 
Due to the height and weight of the conventional probe, undue pressure may 
be exerted not only on the organ under examination, but on other organs in 
contact with organs under examination. 
SUMMARY OF THE INVENTION 
It is accordingly an object of this invention to improve ultrasonic probes, 
wherein the ultrasonic probe can be used to perform a cannula puncture 
with greater stability and accuracy. 
It is another object of this invention to provide an ultrasonic probe which 
can be used in physical contact with internal organs of the body, and at 
least partially beneath the ribs without undue pressure on the organ under 
examination or other organs in contact therewith. 
Briefly, these and other objects are achieved in accordance with a first 
aspect of the invention, by constructing an ultrasonic probe having means 
for receiving a puncturing cannula therethrough, the probe comprising a 
substantially rectangular parallelepiped-shaped support member the height 
of said member being relatively much less than the length or width, a 
plurality of ultrasonic transducer elements arranged in at least one row 
closely adjacent to one edge of the bottom surface of the support member, 
cable means for individually connecting said transducer elements to an 
external processing unit, a slot for guiding the puncturing cannula, said 
slot opening into a first face of said parallelepiped-shaped member 
perpendicular to said bottom surface and adjoining said row of transducer 
elements and said slot being centrally positioned relative to said row of 
transducer elements.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 2, there is shown an ultrasonic probe according to the 
invention including a substantially rectangular support member 6 wherein 
the height is relatively much less than the length or width. Transducer 
elements 7 are arranged in at least one row on a portion 6a of the bottom 
surface of the support member 6. The portion 6a is positioned along one 
edge of the bottom surface and adjacent a face 12 of the support member 6, 
the face being perpendicular to the bottom surface and defining the height 
of the member. 
Preferably, a major portion of the bottom surface of the support member 6 
has been cut away in a shallow depth to form a shoulder 6b substantially 
parallel to the face 12, the portion 6a of the bottom surface lying 
between the shoulder 6b and the perpendicular face 12. 
The transducer elements 7 are individually connected through a cable 8 to a 
display (not shown) through a suitable processing circuit (also not 
shown). The cable 8 preferably exits the member 6 through a face 13 of the 
parallelepiped-shaped support member 6 opposite the face 12 adjacent to 
the portion 6a containing the transducer elements 7. By means of the 
display, tomographs of the organ under examination, as well as the 
cannula, can be shown as the examination proceeds. 
A slot 9 is cut into the face 12 perpendicular to the surface of the 
portion 6a and preferably at the midpoint of the row of transducer 
elements 7. The slot 9 is a groove opening into the face 12 and extending 
from the bottom portion 6a through the top surface of the support member 
6, whereby a shortened cannula can be inserted into the slot substantially 
perpendicular to the bottom portion 6a in which the transducer elements 
are emplaced. 
Preferably the ultrasonic member 6 is fabricated of synthetic resins. 
According to the arrangement of the ultrasonic probe as defined above, the 
height of the probe is relatively quite low, and the guide slot shortened. 
The puncture by the cannula can, therefore, be performed with great 
accuracy and stability with a shortened cannula and without an area within 
which the cannula can be pointed in an arc laterally. 
Likewise if, as shown in FIG. 3, a portion of the ultrasonic probe is 
inserted between the costae 11 and the liver 12 through an incision in the 
abdomen 10, the bottom surface portion 6a having thereon the transducer 
elements 7 of the ultrasonic probe shown in FIG. 2, would be in physical 
contact with the liver 12 or other organs as the case might be. Due to the 
reduced height of the support member 6, and the repositioning of the 
transducer elements 7 near the edge of the bottom surface of the support 
member, it is possible to manipulate the probe for proper alignment of the 
transducer elements relative to the objective, without placing undue 
pressure on the objective organs, or other organs in contact therewith. 
Furthermore, by having the short guide slot 9 in the edge of the support 
member, it is feasible to locate the diseased portion of the liver, for 
example, by the tomography, puncture the liver at the diseased portion, 
and then withdraw the support member from around the cannula via the open 
slot without disturbing the cannula.