METHOD FOR ULTRASOUND EXAMINATION AND ULTRASONIC CONDUCTOR FOR CARRYING OUT THE METHOD

Abstract: By a method for ultrasonic examination is used an ultrasonic conductor (7) for conducting ultrasound from a transducer (4) to an organ (9) in the patient (10) who is to be examined. The ultrasonic conductor (7) consists of a number of arranged fibres (7') of a homogenous material such as glass. By means of a coupling device (5) the transducer (4) transmits an ultrasonic field through the ultrasonic conductor (7) to the organ (9). The ultrasonic conductor (7) then picks up the reflected ultrasonic field and conducts this back to the transducer (4) from where the signal via a cable (3) and by means of generally known computing and monitoring devices is converted into an image (12).

Description: METHOD FOR ULTRASOUND EXAMINATION AND ULTRASONIC CON¬ DUCTOR FOR CARRYING OUT THE METHOD The invention relates to a method for ultrasound exa- mination, such as in connection with ultrasound diag¬ nostics, non-destructive testing or the like, and an ultrasonic conductor for carrying out the method. Ultrasonic systems are known for imaging internal or-. gans. An ultrasonic transducer is brought in contact with the skin of the patient. The transducer trans¬ mits a sound field into the patient. Usually sound with a frequency of between 1 and 10 MHz is applied. The field is reflected with varying intensity from interfaces between the organs of the patient, and these reflections can after suitable computing be u- tilized for imaging the internal organs. Within medi¬ co techniques ultrasound possesses the advantage of being totally harmless and painless. Traditional ultrasound techniques have the disadvan¬ tage that it is difficult to produce useful and high¬ ly detailed images of deeper lying organs, just as bones make the image formation difficult. The latter applies e.g. by scanning of the brain. The object of the invention is therefore to provide a method that overcomes these drawbacks, and which can therefore produce better images than it has so far been possible. This is achieved when the ultrasound is led to an or- 5 gan which is to be examined, by means of an ultra¬ sonic conductor designed for transmitting ultra¬ sound. The ultrasonic conductor can in effect direct the 10. ultrasound to a position close to the organ which is to be examined. Thus the dimensions of the ultrasonic transducer become insignificant, and it becomes pos¬ sible to examine areas that are otherwise hard to get access to. 15 It is expedient if, as referred to in claim 2, the ~same ultrasonic conductor is used to pick up and to return the ultrasound reflected from the organ since this in a simple manner provides the best image pos- 20 sible. If, as referred to in claim 3, the ultrasonic conduc¬ tor by means of an invasive technique is led through the patient to the organ to be examined, it becomes 25 possible to produce detailed images of deeper lying organs or organs which are otherwise hard to get ac¬ cess to. For instance it becomes possible to lead the ultrasonic conductor into the brain through blood vessels supplying blood to the brain. 30 An ultrasonic conductor for carrying out the method according to the invention may be characteristic in that the ultrasonic conductor consists of one or more fibres of a usually homogenous material, as referred to in claim 4. Hereby an efficient transmission of the sound field with only minimum attenuation of the signal is achieved. If every fibre, as referred to in claim 5, is sur¬ rounded by an acoustic insulation material with an acoustic Impedance differing significantly from the acoustic impedance of the homogenous material in the fibre, a number of fibres can be tied closely toge- ther to form a bundle without any risk that sound is transmitted from one fibre to the other. Moreover, the homogenous material may be a liquid, placed in a tube of the insulation material. In a preferred embodiment, as referred to in claim 6, the ultrasonic conductor possesses means for coupling together the ultrasonic conductor with an ultrasonic transducer. Hereby it becomes quick to establish a connection, and at the same time these coupling devi- ces permit the ultrasonic conductor to be used to¬ gether with several different transducers. Finally, such coupling means may contribute to providing a better utilization of the transducer since this may, if necessary, be applied elsewhere, while the ultra- sonic conductor is being placed at the desired point in the patient. If the fibre or fibres are flexible, as referred to in claim 7, the ultrasonic conductor can without dif- ficulty be led along complicated paths. A further preferred embodiment of the ultrasonic con¬ ductor is characteristic in that, as referred to in claim 8, the fibre or fibres have a cross sectional area that varies along the length of the ultrasonic conductor. Thus, it becomes possible to obtain a higher sound Intensity by area at the free end of the ultrasonic conductor. By image formation it is furthermore expedient, as referred to in claim 9, that the ultrasonic conductor consists of a fibre bundle which in turn consists of arranged fibres, i.e. where all individual fibres in 10.. a bundle always have the same position in relation to each other. Thus the ultrasonic conductor may just like that be connected to a sector transducer which is either mechanic or electronic of the phased-array type. 15 Finally, an ultrasonic conductor made of one or seve¬ ral glass fibres, e.g. in the form of light conduc¬ tors, as referred to in claim 10, will always possess good qualities. 20 In the following the invention will be described in closer detail with reference to the drawing, in which fig. 1 shows the principle of the invention exem- 25 plified by scanning of the brain of the patient with an ultrasonic conductor accor¬ ding to the invention, fig. 2 shows an ultrasonic conductor according to 30 the invention connected to an ultraso¬ nic transducer, fig. 3 shows a section through a single fibre in an ultrasonic _• conductor according to the invention, fig. 4 shows a flexible ultrasonic conductor with arranged fibres, and 5 fig. 5 shows a transducer which is provided with a stand-off cell for deflecting the ultra¬ sound. 10 Fig. 1 shows how an ultrasonic conductor 7 according to the invention can be used for the examination of an organ 9, here the brain, in a patient 10. The ultrasonic conductor is led to the brain through. 15 an artery 8. The ultrasonic conductor 7 penetrates into the body at the point 6. By means of a connecting means 5 the ultrasonic con¬ ductor 7 is connected to an ultrasonic transducer 4, 2.0 which in a known manner is connected to an image mo¬ nitor 1, 2 via a cable 3. The examination may for instance be a sector scanning. An ultrasonic field 11 will arise at the end 13 of the ultrasonic conductor 7. The sound field reflected from the brain is again 25 picked up by the sound conductor 7 and returned by this to the transducer 4. The signal picked up can by means of generally known computing produce an image 12 of the organ 9 on the scanner 1, 2. The transducer 4 will of course have to be used as transmitter and 30 receiver in turns. Fig. 2 shows in detail how the image formation can take place when the ultrasonic conductor 7 consists of arranged fibres. The- ultrasound will therefore be led from the end 13 of the ultrasonic conductor 7 di¬ rect to the individual transmitter/receiver crystals In the transducer 4 which need only be an ordinary sector transducer. Fig. 3 illustrates how the sound intensity increases if the cross section of the fibres diminish from a to b. If the ultrasonic conductor 7 is to consist of a fibre bundle, each fibre 7' should be surrounded by - an acoustically insulating material 14 whose acoustic impedance differs significantly from the impedance of the homogenous material in the fibre. Hereby the ul¬ trasound will constantly be reflected from the inter¬ face and hence exclusively be distributed inside the fibre. The insulating material 14 may, if required, be constructed as a tube. This makes it possible for the homogenous sound conducting material to be a li¬ quid. Finally, fig. 4 shows a preferred embodiment where the ultrasonic conductor 7 is made up of arranged flexible fibres 7' with diminishing cross sections. The fibres are insulated from each other. ; Fig. 5 shows an ultrasonic transducer 4 which is re- leasably connected with a stand-off cell 15 which acts as ultrasonic conductor. The stand-off cell is bent at an angle which in the shown example is 90°, and at the same time it has a cross sectional area diminishing away from the transducer 4. In this man¬ ner the stand-off cell may deflect and concentrate the sound field 11 extending from the end of the stand-off cell. The stand-off cell is advantageously made of a homo¬ genous material with low acoustic impedance. The stand-off cell 15 is provided with a bore 17 pa¬ rallel to the sound field 11. Thus the stand-off cell 15 can act as needle control when a needle 16 is in¬ serted into the patient in order that the needle may be observed on its way through the patient thereby preventing damage to internal organs. An ultrasonic conductor according to the invention can be used anywhere where an ultrasonic examination is required. Besides in the medico technique the in¬ vention can also be used e.g. by ultrasonic control. of welding seams and for similar tasks. The ultraso¬ nic conductor 7 can also be used where an ultrasonic field is to be turned e.g. 90°. The ultrasonic conductor 7 according to the invention can be used together with all known types of ultraso¬ nic transducers. For medical purposes it may thus be connected with multi-element transducers, sector transducers (mechanical as well as phased-array) and single-element transducers. The ultrasonic conductor can also be used together with a puncture stand-off cell and thus lead the ultrasound from the transducer to the place where a needle is to be inserted. The ultrasonic conductor 7 can on the whole be made of any homogenous material. Thus glass fibres have proved to be advantageous since they have a high de¬ gree of homogeneity, small diameter, good sound con¬ ductance and a high flexibility. But fibres of metal or plastics can also ,be used. For certain purposes one can moreover imagine that the individual fibres are twisted or wound in a suitable manner, just as the individual fibres may be given the length and/or diameter that produces the required result. It should be added that ultrasonic conductors accord¬ ing to the invention can also be used for removing e.g. tartar or kidney stone, in that the sound may be transmitted direct to the stone that is to be remo¬ ved. Finally one could imagine fibres of varying ma¬ terial in order that there will be fields with higher or lower impedance. Hereby an easier penetration in¬ to tissue etc. is achieved.

Claims: P A T E N T C L A I M S 1. Method for ultrasound examination, such as in con¬ nection with ultrasound diagnostics, non-destructive testing or the like, c h a r a c t e r i z e d in that ultrasound is led to an organ (9) which is to be examined, by means of an ultrasonic conduσtur (7, 15) designed to transmit ultrasound. 2. Method according to claim 1, c h a r a c t e ¬ r i z e d in that the ultrasonic conductor (7, 15) is also used for picking up the reflected sound sig-. nal from the organ (9) and for conducting the re¬ flected signal back to a monitoring device for image formation or the like. 3. Method according to claims 1-2 and especially for ultrasound diagnostics, c h a r a c t e r i z e d in that by means of an invasive method the ultrasonic conductor (7) is led through the patient to the area which is to be examined by e.g. ultrasonic scanning. 4. Ultrasonic conductor for carrying out the method according to claims 1-3, c h a r a c t e r i z e d in that the ultrasonic conductor (7, 15) consists of one or several fibres of an unusually homogenous ma¬ terial. 5. Ultrasonic conductor according to claim 4, c h a ¬ r a c t e r i z e d in that each fibre (7) is surrounded by an insulating material (14) which has an acoustic impedance - differing significantly from the acoustic impedance of the homogenous material in the fibre. 6. Ultrasonic conductor according to claim 4-5, c h a c t e r i z e d in that the ultrasonic conduc¬ tor (7) has means (5) for coupling together the ul¬ trasonic conductor with an ultrasonic transducer (4). 7. Ultrasonic conductor according to claim 4, σ h a - a σ t e r i z e d in that the ultrasonic conductor (15) is connected to an ultrasonic transducer (4) and has a curved shape for deflecting the sound field (11) and a needle control (17) parallel to the field (11). 8. Ultrasonic conductor according to claims 4-6, c h a r a c t e r i z e d in that the fibre or fi¬ bres is/are flexible. 9. Ultrasonic conductor according to claims 4-8, c h a r a c t e r i z e d in that the fibre (15) or fibres (7) has/have a cross sectional area varying along the length of the ultrasonic conductor (7, 15). 10. Ultrasonic conductor according to claims 4-9 and consisting of a bundle of fibres, c h a r a c t e - z e d in that the bundle consists of arranged fi¬ bres, i.e. that all individual fibres in the bundle always have the same position in relation to each other. 11. Ultrasonic conductor according to claims 4-6 and 8-10, c h a r a c t e r i z e d in that the ultraso¬ nic conductor is made of-one or several glass fibres, such as light conductors.

Inventors: DRUE HERBERT RENALD CHRISTIAN, DRUE, HERBERT, RENALD, CHRISTIAN
Applicants: MEDICAL INNOVATION CO, MEDICAL INNOVATION COMPANY A/S
Application year: 1986
Main classification: A61B8
IPC codes: A61B8, G10K11