Patent Abstract:
An ultrasound-guided piercing needle constituting the internal needle of an indwelling needle has ridged and grooved portions which reflect ultrasonic waves. The ridged and grooved portions comprise grooves, which are disposed on the outer periphery near the tip having a blade face, and ridges, which are arranged on both sides of the grooves.

Full Description:
TECHNICAL FIELD 
     The present invention relates to an ultrasound-guided piercing needle for piercing a patient while detecting a position of the piercing needle utilizing the reflection of ultrasonic waves, as well as to an indwelling needle incorporating the piercing needle. 
     BACKGROUND ART 
     For example, at the time of transfusion of a high-concentration pabulum into a patient, an indwelling needle including a catheter (outer needle) and a piercing needle (inner needle) is made to pierce the patient, the piercing needle is evulsed with the catheter left in a pierced state, a guide wire is inserted through the catheter to reach a blood vessel (vein) near the heart, the catheter is evulsed, a central arterial catheter is inserted along the guide wire into the blood vessel, the guide wire is removed so that only the central arterial catheter is left indwelling in the pierced state, a transfusion line through which a pabulum, a medicinal liquid, or the like is supplied is connected to the central arterial catheter, and a transfusion is conducted. 
     In the case that such an indwelling needle is made to pierce a blood vessel, for example, ultrasonic waves are emitted from an ultrasonic imaging device, thereby confirming the position of the blood vessel to be pierced. In addition, the piercing needle, which is in the pierced state, is irradiated with ultrasonic waves, and a surgical procedure is carried out while confirming the position of the piercing needle through an image obtained based on the reflected waves. 
     Hitherto, as such an indwelling needle, indwelling needles in which an outer circumferential surface of a piercing needle (inner needle) is provided with a helical groove or a V-shaped groove in a recessed form have been known (see, for example, Japanese Patent No. 3171525 and Japanese Laid-Open Patent Publication No. 03-228748). Upon using this type of indwelling needle, the piercing needle is made to pierce a diseased part of a patient, the pierced part is irradiated with ultrasonic waves emitted from an ultrasonic imaging device, whereupon the ultrasonic waves are reflected by an air layer in the helical groove or the V groove, and the reflected waves are received by the ultrasonic imaging device in order to obtain a picked-up image (echo image) of the piercing needle. 
     SUMMARY OF INVENTION 
     Meanwhile, in order to accurately grasp the position of the piercing needle, as mentioned above, it is important to obtain a clear echo image. In order to obtain a clear echo image, reflected waves with sufficient intensity must be returned from the piercing needle to a probe of the ultrasonic imaging device. Therefore, it is desired to develop an ultrasound-guided piercing needle, which ensures that stronger reflected waves, and hence a clearer echo image, can be obtained. 
     The present invention has been made in consideration of the above-mentioned problems. Accordingly, it is an object of the present invention to provide an ultrasound-guided piercing needle and an indwelling needle, which ensure that ultrasonic waves can be reflected more effectively, whereby the position of the piercing needle in a living body can be confirmed assuredly and with high accuracy. 
     According to the present invention, there is provided an ultrasound-guided piercing needle having a ridged and grooved portion, which reflects ultrasonic waves, the ridged and grooved portion comprising a grooved portion provided on an outer circumferential surface near a distal portion having a blade face, and ridged portions provided on both sides of the grooved portion. 
     In this manner, since the ridged and grooved portion includes the grooved portion and the ridged portions provided on both sides of the grooved portion, ultrasonic waves are reflected not only by the grooved portion, but also by the ridged portions. Therefore, ultrasonic waves can be reflected assuredly and suitably, and can be detected by the ultrasonic imaging device. Consequently, upon piercing a patient, the ultrasound-guided piercing needle can be confirmed assuredly and with high accuracy by the ultrasonic imaging device, whereby a safe and assured procedure can be carried out while confirming the position of the ultrasound-guided piercing needle. 
     In addition, in the aforementioned ultrasound-guided piercing needle, the ridged and grooved portion may be formed in an annular shape on the outer circumferential surface, and a plurality of ridged and grooved portions may be provided along an axial direction of the ultrasound-guided piercing needle. 
     With such a configuration, the formation of the ridged and grooved portion in an annular form on the outer circumferential surface enables the entire circumference to act as a reflecting surface, so that when piercing is carried out, ultrasonic waves can be reflected effectively, irrespective of the position around the axis of the ultrasound-guided piercing needle. In addition, since plural ridged and grooved portions are provided along the axial direction of the ultrasound-guided piercing needle, the number of parts that provide suitable reflection of ultrasonic waves is increased significantly. Therefore, ultrasonic waves can be reflected effectively, and more sufficient reflected waves can be obtained. Consequently, the position of the ultrasound-guided piercing needle by the ultrasonic imaging device can be confirmed with higher accuracy. 
     Further, in the aforementioned ultrasound-guided piercing needle, the plurality of ridged and grooved portions may be formed such that the ridged portions of adjacent ones of the ridged and grooved portions are continuous with each other. 
     By forming the ridged and grooved portions continuously along the axial direction of the ultrasound-guided piercing needle, ultrasonic waves can be reflected more effectively, and more sufficient reflected waves can be obtained. As a result, the position of the ultrasound-guided piercing needle by the ultrasonic imaging device can be confirmed with higher accuracy. 
     In addition, in the aforementioned ultrasound-guided piercing needle, the ridged and grooved portion may be formed in a helical shape extending around the outer circumferential surface at least a plurality of times. 
     By forming the ridged and grooved portion in this manner, the entire circumference acts as a reflecting surface, so that when piercing is carried out, ultrasonic waves can be reflected effectively, irrespective of the position around the axis of the ultrasound-guided piercing needle. In addition, the number of parts provided for suitable reflection of ultrasonic waves is increased, so that more sufficient reflected waves can be obtained. Consequently, the position of the ultrasound-guided piercing needle by the ultrasonic imaging device can be confirmed with higher accuracy. 
     Further, in the aforementioned ultrasound-guided piercing needle, the grooved portion may be arcuate in cross section. 
     According to the above configuration, an inner wall surface of the grooved portion constitutes an arcuate reflecting surface. Thus, even if the piercing angle changes, ultrasonic waves incident on the grooved portion can be reflected in substantially the same direction as the direction of incidence. Therefore, ultrasonic waves can be reflected suitably, and as a result, the position of the ultrasound-guided piercing needle by the ultrasonic imaging device can be confirmed with higher accuracy. 
     In addition, in the aforementioned ultrasound-guided piercing needle, the ridged portions may be arcuate in cross section. 
     According to the above configuration, outer wall surfaces of the ridged portions constitute arcuate reflecting surfaces. Thus, even if the piercing angle changes, ultrasonic waves incident on the ridged portions can be reflected in substantially the same direction as the direction of incidence. Therefore, ultrasonic waves can be reflected suitably, and as a result, the position of the ultrasound-guided piercing needle by the ultrasonic imaging device can be confirmed with higher accuracy. 
     Further, according to the present invention, there is provided an indwelling needle including an inner needle and an outer needle in which the inner needle is inserted, wherein the inner needle is configured as an ultrasound-guided piercing needle having a ridged and grooved portion, which reflects ultrasonic waves. The ridged and grooved portion further comprises a grooved portion provided on an outer circumferential surface near a distal portion having a blade face, and ridged portions provided on both sides of the grooved portion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an overall view showing the configuration of an indwelling needle having an ultrasound-guided piercing needle according to one embodiment of the present invention; 
         FIG. 2A  is a plan view showing the configuration of a catheter and an outer needle hub shown in  FIG. 1 ; 
         FIG. 2B  is a partially omitted enlarged sectional view, taken along an axial direction, of a distal portion and portions in the vicinity thereof of the catheter shown in  FIG. 2A ; 
         FIG. 3A  is a plan view showing the configuration of an ultrasound-guided piercing needle and an inner needle hub according to one embodiment of the present invention; 
         FIG. 3B  is a enlarged side view, shown partially in cross section, of an ultrasound-guided piercing needle according to one embodiment of the present invention; 
         FIG. 4  is a partially omitted enlarged sectional view showing a part near a distal portion of an indwelling needle having an ultrasound-guided piercing needle according to one embodiment of the present invention; 
         FIG. 5  is a schematic illustration showing the manner in which an indwelling needle, having an ultrasound-guided piercing needle according to one embodiment of the present invention, is made to pierce a patient while the ultrasound-guided piercing needle is detected by an ultrasonic imaging device; 
         FIG. 6  is an enlarged schematic illustration of a condition in which ultrasonic waves, which are irradiated on an indwelling needle having an ultrasound-guided piercing needle according to one embodiment of the present invention, are reflected; 
         FIG. 7  is a schematic illustration of a mode of usage, in which an ultrasound-guided piercing needle according to one embodiment of the present invention is made to directly pierce a patient; 
         FIG. 8  is an enlarged side view showing grooved portions of an ultrasound-guided piercing needle according to a first modification; and 
         FIG. 9  is an enlarged side view showing grooved portions of an ultrasound-guided piercing needle according to a second modification. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An ultrasound-guided piercing needle and an indwelling needle according to the present invention will be described in relation to preferred embodiments with reference to the attached drawings. 
       FIG. 1  is an overall view showing a configuration of an indwelling needle  12  having an ultrasound-guided piercing needle  10  (hereinafter referred to simply as a “piercing needle”) according to an embodiment of the present invention. Incidentally, for convenience of description, in each of the attached drawings (exclusive of some drawings), the axial direction of the indwelling needle  12  and the axial direction of each of members constituting the indwelling needle  12  are indicated by the arrow X. In addition, a direction toward distal portions of the indwelling needle  12  and members thereof is denoted by the arrow X 1 , whereas a direction toward proximal portions of the members is denoted by the arrow X 2 . 
     As shown in  FIG. 1 , the indwelling needle  12  according to one configuration example includes a catheter  14 , an outer needle hub  16  connected to a proximal portion of the catheter  14 , a piercing needle  10  inserted into the interior of the catheter  14 , and an inner needle hub  18  connected to a proximal portion of the piercing needle  10 . 
     The inner needle hub  18  is configured to fit into the interior of the outer needle hub  16 . In  FIG. 1 , a condition is shown in which a connected body of the piercing needle  10  and the inner needle hub  18  is fitted into a connected body of the catheter  14  and the outer needle hub  16 . In this condition, a blade face  11 , which is formed at a distal portion of the piercing needle  10 , is exposed (protruded) from a distal end of the catheter  14 . A syringe  30  can be connected to a proximal portion of the inner needle hub  18  (see  FIG. 5 ). 
       FIG. 2A  is a plan view showing a configuration of the catheter  14  and the outer needle hub  16  of the indwelling needle  12  shown in  FIG. 1 . In the indwelling needle  12  according to one exemplary configuration, the catheter  14  constitutes an outer needle, which is formed, for example, from a transparent resin material. The catheter  14  has an appropriate degree of elasticity and is formed in a tubular shape so as to surround the piercing needle  10 . The catheter  14  reaches the vicinity of the distal end of the piercing needle  10 . When the distal end of the piercing needle  10  is inserted into a blood vessel, the catheter  14  also is inserted into the same blood vessel. 
     Examples of materials constituting the catheter  14  may include various flexible resins such as ethylene-tetrafluoroethylene copolymer (ETFE), polyurethane, and polyether nylon resin. Examples of materials constituting the outer needle hub  16  may include polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc., polyvinyl chloride, polymethyl methacrylate, polycarbonates, polybutadiene, polyamides, and polyesters. 
       FIG. 2B  is a partially omitted enlarged sectional view, taken along the axial direction, of a distal portion and a portion in the vicinity thereof of the catheter  14 . As shown in  FIG. 2B , an inner circumferential surface proximate a distal portion of the catheter  14  is formed with inner circumferential grooved portions  20 , which are hollowed in a shape protuberant to the outer circumferential side. In the example shown in the drawing, the inner circumferential grooved portions  20  are substantially semicircular in cross section, are formed in an annular shape with a substantially constant depth in the circumferential direction, and are formed at predetermined intervals in the axial direction and over a predetermined range (denoted by A in  FIG. 2A ). 
     The distance L 1  from a maximal distal portion of the catheter  14  to the inner circumferential grooved portion  20  on the distal side thereof is set, for example, from 0 to 3 mm, and more preferably, from 1 to 2 mm. The distance L 2  in the axial direction (X-direction) from the maximal distal portion of the catheter  14  to the inner circumferential grooved portion  20  on the proximal side thereof is set, for example, from 2 to 10 mm, and more preferably, from 6 to 8 mm. The depth in the radial direction of the inner circumferential grooved portion  20  is set, for example, from 10 to 25 μm. The groove pitch (the interval in the axial direction) of the plurality of inner circumferential grooved portions  20  is set, for example, from 0.2 to 0.5 mm. 
     Incidentally, the inner circumferential grooved portions  20  are not restricted to being formed as annular grooves, which are formed at an interval in the axial direction, but may comprise a groove, which extends helically in the axial direction. Further, the inner circumferential grooved portions  20  may be omitted. 
       FIG. 3A  is a plan view showing a configuration of a piercing needle  10  and an inner needle hub  18  according to an embodiment of the present invention. In an indwelling needle  12  according to one exemplary configuration, the piercing needle  10  constitutes an inner needle. The piercing needle  10  comprises a hollow tube formed at a distal portion thereof with a blade face  11 , which is inclined relative to the axis of the piercing needle  10 . 
     The material constituting the piercing needle  10  is a material from which a sharp blade edge can be formed thereon to provide a sufficient piercing force (penetrating force), and which has strength necessary for piercing. Examples of suitable materials include stainless steel, aluminum alloys, and copper alloys. 
     A proximal portion of the piercing needle  10  is connected to and held by a distal portion of the inner needle hub  18 . Examples of materials constituting the inner needle hub  18  include the same materials as those of the outer needle hub  16 , as mentioned above. As shown in  FIG. 3A , an outer circumferential surface in the vicinity of the distal portion of the piercing needle  10  (a predetermined range on the proximal side relative to the blade face  11 ) is formed with ridged and grooved portions  22 , for reflecting ultrasonic waves over a predetermined range along the axial direction of the piercing needle  10 . 
       FIG. 3B  is an enlarged side view partially in cross section showing the ridged and grooved portions  22  of the piercing needle  10  shown in  FIG. 3A . The outside diameter D of the piercing needle  10  is set, for example, from 0.7 to 0.8 mm. In the present embodiment, the ridged and grooved portions  22  are formed in an annular shape on the outer circumferential surface of the piercing needle  10 . Plural ridged and grooved portions  22  are provided at intervals along the axial direction (X-direction) of the piercing needle  10 . In the example shown in the drawing, the interval L 3  of the ridged and grooved portions  22  in the axial direction may be set to a constant value. In this case, the interval L 3  is set, for example, from 200 to 500 μm. 
     The distance L 4  (see  FIG. 3A ) along the axial direction from a maximal distal portion of the piercing needle  10  to the ridged and grooved portion  22  on the distal side is set, for example, from 0.3 to 5 mm. The distance L 5  (see  FIG. 3A ) along the axial direction from the maximal distal portion of the piercing needle  10  to the ridged and grooved portion  22  on the proximal side is set, for example, from 5 to 50 mm. 
     Incidentally, in the example of the piercing needle  10  shown in the drawing, the interval L 3  of the ridged and grooved portions  22  in the axial direction is set to a constant value. However, some or all of the intervals of the plural ridged and grooved portions  22  may be set to a different value. For instance, the interval of the ridged and grooved portions  22  may be set to be smaller on the distal side of the piercing needle  10  (or the interval of the ridged and grooved portions  22  may be set to be greater on the proximal side of the piercing needle  10 ). 
     As shown in  FIG. 3B , the ridged and grooved portion  22  includes the grooved portion  24 , which is formed in an annular shape so as to protrude toward the inner circumferential side, and the ridged portions  26 , which are disposed on both sides (both sides in the axial direction) of the grooved portion  24 , and are formed in an annular shape so as to protrude toward the radially outer side. 
     In the present embodiment, the grooved portion  24  is arcuate in cross section, and is formed with a substantially constant depth over the circumferential direction. The width W 1  of the grooved portion  24  in the axial direction is set, for example, from 30 to 100 μm. The depth H 1  of the grooved portion  24  in the radial direction is set, for example, from 5 to 20 μm. 
     In the present embodiment, the ridged portion  26  is arcuate in cross section, and is formed with a substantially constant height over the circumferential direction. The width W 2  of the ridged portion  26  in the axial direction is set, for example, from 5 to 20 μm. The height H 2  of the ridged portion  26  in the radial direction is set, for example, from 1 to 15 μm. Thus, as clearly shown in  FIG. 3B , the outer diameter of the ridged portion  26  is greater than the outside diameter D of the outer circumferential surface of the piercing needle  10 . 
     Incidentally, the ridged and grooved portions  22 , which are configured as described above, can be formed comparatively easily by subjecting a tubular blank material (work) to machining work, such as plastic working, cutting, and electric discharge machining. 
       FIG. 4  is a partially omitted enlarged sectional view showing a condition in which a piercing needle  10  according to one embodiment of the present invention is inserted into a catheter  14 , such that a distal portion, inclusive of a blade face  11 , of the piercing needle  10  is exposed (protruded) from a distal portion of the catheter  14 . The inside diameter of the catheter  14  is set to be approximately equal to or slightly larger than the outside diameter of the ridged portions  26 , so that the piercing needle  10 , provided with the ridged portions  26  thereon, can be inserted into the catheter  14 . 
     Further, as shown in  FIG. 4 , in the present embodiment, inner circumferential grooved portions  20  and ridged and grooved portions  22  of the catheter  14  and the piercing needle  10  are formed such that, in a condition in which the distal portion of the piercing needle  10  is exposed (protruded) a predetermined length from the distal portion of the catheter  14 , the phase in the axial direction of the plurality of inner circumferential grooved portions  20  and the phase in the axial direction of the plurality of ridged and grooved portions  22  are shifted from each other. 
     The indwelling needle  12  including the piercing needle  10  according to the present embodiment is basically constructed as described above. Next, a method of using the indwelling needle  12  and operations and effects of the indwelling needle  12  will be described. 
     Prior to piercing by the indwelling needle  12 , a syringe  30  is connected to a proximal portion of an inner needle hub  18 , as shown in  FIG. 5 . The syringe  30  includes a hollow cylindrical syringe main body  32 , and a plunger  34  inserted inside the syringe main body  32 . The syringe main body  32  is provided at a distal portion thereof with a connection port  36 , which is connected to a proximal portion of the inner needle hub  18 . Consequently, the syringe  30  communicates with the interior of the inner needle hub  18  through the connection port  36 . 
     To perform piercing using the indwelling needle  12 , first, as shown in  FIG. 5 , the indwelling needle  12  inclusive of the piercing needle  10  is gripped by a health care staff worker such as a doctor or the like, and is made to pierce a blood vessel (vein) of a patient  50 . The piercing needle  10  is gradually inserted toward a desired area, whereupon the distal portion of the piercing needle  10  is advanced while cutting open a body tissue  52 . In this case, as shown in  FIG. 6 , the piercing needle  10  is inserted into the interior of the catheter  14 , and in this condition, the ridged and grooved portions  22  of the piercing needle  10  are located inside the catheter  14 . Therefore, the indwelling needle  12  is allowed to pierce the patient while the ridged and grooved portions  22  of the piercing needle  10  are prevented from coming into contact with the body tissue  52 . 
     On the other hand, simultaneously with piercing of the patient by the indwelling needle  12 , a probe  42  of an ultrasonic imaging device  40  is pressed onto the vicinity of the pierced part of the patient  50 , and irradiation of the patient with an echo beam (ultrasonic waves) E is conducted. Incidentally, the probe  42  is configured so as to be capable of emitting the echo beam E as well as receiving reflected waves (a reflected echo) of the echo beam E. 
     The echo beam E is emitted in the direction from a skin surface toward the inside of the patient  50 , and a distal portion of the indwelling needle  12  is irradiated with the echo beam E. Then, as shown in  FIG. 6 , the echo beam E is reflected toward the side of the probe  42  from inner wall surfaces of the inner circumferential grooved portions  20 , which are formed at the inner circumferential surface of the catheter  14 . Similarly, the echo beam E is reflected by air that is sealed inside the inner circumferential grooved portions  20 . Ultrasonic waves (reflected waves) reflected by the inner circumferential grooved portions  20  are represented as a reflection echo E 1 . In this case, the reflection echo E 1 , which is reflected by the inner wall surfaces of the inner circumferential grooved portions  20 , is not attenuated by air that exists in the inner circumferential grooved portions  20 . Therefore, the reflection echo E 1  has an intensity approximately equal to the intensity of the emitted echo beam E. The reflection echo E 1  is received by the probe  42 . 
     In addition, the echo beam E is transmitted through the catheter  14 , so as to be reflected from the ridged and grooved portions  22  toward the side of the probe  42 . Reflected waves reflected by the ridged and grooved portions  22  are represented as a reflection echo E 2 . The reflection echo E 2 , which is reflected by the ridged and grooved portions  22 , includes a reflection component reflected by the grooved portion  24 , and another reflection component reflected by the ridged portions  26 . The reflection echo E 2  reflected by the ridged and grooved portions  22  is received by the probe  42 . 
     As mentioned above, in the present embodiment, the grooved portion  24  is arcuate in cross section and the inner wall surface thereof constitutes an arcuate reflecting surface. The ridged portions  26  are arcuate in cross section and outer wall surfaces thereof constitute arcuate reflecting surfaces. Therefore, even if the piercing angle θ (see  FIG. 5 ) of the indwelling needle  12  changes, the echo beam E emitted from the probe  42  can be reflected by the inner wall surfaces of the grooved portions  24  as well as by the outer wall surfaces of the ridged portions  26  toward the side of the probe  42 . 
     When reflected waves (reflection echoes E 1 , E 2 ) of the echo beam E are received by the probe  42 , data concerning the reception thereof is output from the probe  42  through lead wires  44  and is sent to a control unit (not shown) of the ultrasonic imaging device  40  in order to be processed and thereafter displayed as an image on a display unit  46 . More specifically, an image of the catheter  14  and the piercing needle  10 , which is displayed on the display unit  46 , is displayed in a linear form as a length along the axial direction of the ridged and grooved portions  22 , which have been detected by the ultrasonic imaging device  40 . Consequently, whether or not the distal portion of the piercing needle  10  has reached the blood vessel (vein) of the patient  50  can be confirmed by observing the display unit  46 . 
     As a result, the vicinity of the distal portion of the piercing needle  10  is clearly displayed as an image on the display unit  46  of the ultrasonic imaging device  40 , whereby the position of the piercing needle  10  that makes up the indwelling needle  12  can be confirmed with high accuracy. 
     Then, the doctor or the like moves the piercing needle  10  and the probe  42  while observing the display unit  46 , so as to guide the piercing needle  10  toward the blood vessel of the patient  50 . In this instance, the indwelling needle  12  is advanced while the plunger  34  of the syringe  30  is withdrawn appropriately. When the piercing needle  10  has pierced the blood vessel correctly, blood is introduced through the connection port  36  of the syringe  30  into the syringe main body  32 , resulting in flashback. 
     Once piercing of the blood vessel by the piercing needle  10  has been confirmed in this manner, the piercing needle  10  and the syringe  30  are removed, thereby leaving the catheter  14  and a guide wire (not shown) inserted in the blood vessel through the catheter  14 , after which the catheter  14  is removed. Next, a central venous catheter (not shown) is placed along the guide wire in an indwelling state in the blood vessel. Subsequently, a transfusion line (not shown) is connected to a central arterial catheter, and pabulum, a medicinal liquid, or the like is supplied into the blood vessel. 
     At the time of evulsing the piercing needle  10  while leaving the catheter  14  behind, the piercing needle  10  is evulsed to the exterior of the patient&#39;s body through the interior (lumen) of the catheter  14 , so that the ridged and grooved portions  22  of the piercing needle  10  are prevented from coming into contact with body tissue  52 , in the same manner as when the patient is pierced with the piercing needle. 
     As described above, according to the piercing needle  10  of the present embodiment, the ridged and grooved portion  22  is composed of the grooved portion  24  and the ridged portions  26  provided on both sides of the grooved portion  24 , such that ultrasonic waves are reflected not only at the grooved portion  24  but also on the ridged portions  26 . Therefore, ultrasonic waves can be reflected assuredly and suitably, so as to be detected by the ultrasonic imaging device  40 . As a result, the position of the piercing needle  10 , which is made to pierce the patient, can be confirmed by the ultrasonic imaging device  40  assuredly and with high accuracy, whereby a safe and assured procedure can be carried out while confirming the position of the piercing needle  10 . 
     In addition, in the present embodiment, the ridged and grooved portions  22  are disposed in an annular form. Therefore, the entire circumference of the ridged and grooved portions  22  constitutes a reflecting surface. Therefore, ultrasonic waves can be effectively reflected, irrespective of the position around the axis of the piercing needle  10  at the time of piercing. Further, since plural ridged and grooved portions  22  are provided along the axial direction of the piercing needle  10 , the number of parts provided for suitable reflection of ultrasonic waves is increased. Therefore, ultrasonic waves can be reflected effectively, and more sufficient reflected waves can be obtained. Consequently, the position of the piercing needle  10  can be confirmed with higher accuracy by the ultrasonic imaging device  40 . 
     Further, in the present embodiment, the grooved portion  24  is arcuate in cross section, and the inner wall surface thereof constitutes an arcuate reflecting surface. The ridged portions  26  are arcuate in cross section, and the outer wall surfaces thereof constitute arcuate reflecting surfaces. Therefore, even in the case that the piercing angle θ (see  FIG. 5 ) of the indwelling needle  12  changes, ultrasonic waves emitted from the probe  42  can be reflected back toward the side of the probe  42  by the inner wall surface of the grooved portion  24  and the outer wall surfaces of the ridged portions  26 . In other words, ultrasonic waves can be reflected toward the side of the probe  42 , whereby the position of the indwelling needle  12  can be confirmed irrespective of the piercing angle θ of the indwelling needle  12 . 
     Furthermore, the inner circumferential grooved portions  20  are formed on the inner circumferential surface of the catheter  14 , so that ultrasonic waves also are reflected at the inner circumferential grooved portions  20 . Therefore, the intensity of the reflected waves, which are received by the probe  42 , can be enhanced, whereby a clearer echo image can be obtained. As a result, the position of a distal portion of the indwelling needle  12  can be confirmed with high accuracy. 
     Incidentally, while a mode of use of the piercing needle  10  according to the present embodiment has been described above with reference to a case in which the piercing needle  10  is configured as an inner needle of an indwelling needle  12 , which includes both an outer needle and the inner needle, the piercing needle  10  of the present invention also is applicable to cases in which the piercing needle  10  is made to directly pierce a patient to capture a blood vessel of the patient, without using a catheter  14 , as shown in  FIG. 7 . In this case, for example, a Y hub (not shown) is connected to a proximal portion of the inner needle hub  18 , and a guide wire and a central arterial catheter are passed through the Y hub, the inner needle hub  18 , and the piercing needle  10 . Thus, a procedure, which is the same or similar to the aforementioned procedure, can be carried out. Furthermore, in such a mode of use, ultrasonic waves (the echo beam E) can be reflected by the ridged and grooved portions  22  assuredly and suitably, and the position of the piercing needle  10 , in a state of piercing the patient, can be confirmed by the ultrasonic imaging device  40  assuredly and with high accuracy, so that a safe and assured procedure can be carried out while confirming the position of the piercing needle  10 . 
     In addition, while a mode of use of the piercing needle  10  according to the present embodiment has been described above with reference to a case in which the piercing needle  10  is used as a guide wire introducing needle in order to place a central arterial catheter in an indwelling state by a so-called Seldinger catheter technique, the piercing needle  10  of the present invention can also be used as an indwelling needle for performing a transfusion by being set in an indwelling manner in a deletion blood vessel. The piercing needle  10  can also be used as a biopsy needle for sampling a portion of a body tissue or cells, or the like. 
       FIG. 8  is a side view showing the configuration of a distal portion, and portions in the vicinity thereof, of an ultrasound-guided piercing needle  10   a  (hereinafter referred to simply as a “piercing needle  10   a ”) according to a first modification. In the piercing needle  10   a  according to the first modification, plural ridged and grooved portions  22  may be formed such that ridged portions  26  of the adjacent ridged and grooved portions  22  are continuous (connected) with each other. By the ridged and grooved portions  22  of the piercing needle  10  being formed in this manner, the amount of reflected waves directed toward the side of the probe  42  can be increased, compared with the case of the piercing needle  10  according to the basic form thereof, as described above in relation to the aforementioned embodiment. As a result, confirmation of the position of the piercing needle  10   a  by the ultrasonic imaging device  40  can be performed with higher accuracy. 
       FIG. 9  is a side view showing the configuration of a distal portion, and portions in the vicinity thereof, of an ultrasound-guided piercing needle  10   b  (hereinafter referred to simply as a “piercing needle  10   b ”) according to a second modification. In the piercing needle  10   b  according to the second modification, a ridged and grooved portion  27  having a grooved portion  28  and ridged portions  29  on both sides of the grooved portion  28  may be formed in a helical shape, which extends in the axial direction of the piercing needle  10   b , while also extending around the outer circumferential surface of the piercing needle  10   b  at least a plurality of times. By configuring the ridged and grooved portion  27  in this manner, ultrasonic waves can be effectively reflected, and more sufficient reflected waves can be obtained, similar to the case of the ridged and grooved portions  22  described above. Consequently, confirmation of the position of the piercing needle  10   b  by the ultrasonic imaging device  40  can be performed with enhanced accuracy. 
     In addition, by forming the ridged and grooved portion  27  of the piercing needle  10   b  in a helical shape, when the piercing needle  10   b  is inserted into the catheter  14 , it is ensured that the phase in the axial direction of the plurality of inner circumferential grooved portions  20 , and the phase in the axial direction of the ridged and grooved portion  27  can easily be shifted from each other. 
     Further, the inner circumferential grooved portion  20  of the catheter  14  may be formed in a helical shape having a different angle from that of the ridged and grooved portion  27 , or alternatively, the inner circumferential grooved portion  20  of the catheter  14  may be formed in a helical shape in a different direction from that of the ridged and grooved portion  27 . With such a configuration as well, the phase in the axial direction of the inner circumferential grooved portion  20 , and the phase in the axial direction of the ridged and grooved portion  27  can easily be shifted from each other. 
     When the phase in the axial direction of the inner circumferential grooved portion(s)  20 , and the phase in the axial direction of the ridged and grooved portion(s)  27  are shifted from each other, attenuation in the intensity of the reflected ultrasonic waves can be restrained. 
     Incidentally, the present invention is not restricted to the above-described embodiments, and naturally, various configurations are possible without deviating from the gist of the invention.

Technology Classification (CPC): 0