WO2003095000A1

WO2003095000A1 - Syringe plungers, injectors, injector systems and methods for use in agitation of multi-component fluids

Info

Publication number: WO2003095000A1
Application number: PCT/US2003/014181
Authority: WO
Inventors: David M. Reilly; Gerald W. Callan; Kevin P. Cowan
Original assignee: Medrad, Inc.
Priority date: 2002-05-07
Filing date: 2003-05-07
Publication date: 2003-11-20

Abstract

An injector (10) for use in connection with a syringe (20) includes a syringe plunger (100) disposed therein to inject an injection fluid. The injector (10) includes a linear drive member, which can, for example, include a first attachment member (54) to form a connection with the syringe plunger (100). The injector (10) also includes a rotational drive member (54) to rotate an agitating mechanism of the syringe plunger (100). The rotational drive member (54) can mechanically couple with the agitating mechanism. In one embodiment, the rotational drive member (54) is positioned within the linear drive member and includes a second attachment member extending from the front of the linear drive member to couple with the agitating mechanisms. The rotational drive member can also couple with the agitation mechanisms via electromagnetic energy. The injector preferably further includes a control system to control the rotational drive member (54). The control system can, for example, control the rotational drive member (54) in a non-continuous manner (for example, to pulse the rotation of the agitation mechanism).

Description

SYRINGE PLUNGERS, INJECTORS, INJECTOR

SYSTEMS AND METHODS FOR USE IN AGITATION

OF MULTI-COMPONENT FLUIDS

BACKGROUND OF THE INVENTION

The present invention relates generally to creation and maintenance of multi- component fluids, and, especially, to syringe plungers, injectors, injector systems and methods for agitation of multi-component fluids to be injected into a patient.

hi a number of medical procedures, it is desirable to inject a multi-component injection medium into a patient. An example of such a medical procedure is ultrasound imaging.

Ultrasound imaging creates images of the inside of the human body by broadcasting ultrasonic energy into the body and analyzing the reflected ultrasound energy. Differences in reflected energy (for example amplitude or frequency) appear as differences in gray scale or color on the output images. As with other medical imaging procedures, contrast-enhancing fluids (often referred to as contrast media) can be injected into the body to increase the difference in the reflected energy and thereby increase the contrast in the image viewed by the operator.

For ultrasonic imaging, the most common contrast media contain many small bubbles. The difference in density of bubbles when compared to water, and thus their difference in sound transmission, makes small gas bubbles excellent means for scattering ultrasound energy. Small solid particles can also serve to scatter ultrasonic energy. Such particles are typically on the order of 1 to 10 microns (that is, 10^"6 to 10^"5 meters) in diameter. These small particles can pass safely through the vascular bed.

Contrast media suitable for use in ultrasound are supplied in a number of forms.

Some of these contrast media are powders to which liquid is added just before use. The powder particles cause a gas bubble to coalesce around them. The powder must be mixed with a liquid, and the mixture must be agitated with just the right amount of vigor to get the optimum creation of bubbles. Another type of contrast medium is a liquid that is agitated vigorously with air. There are no solid particles to act as nuclei, but the liquid is a mixture of several liquid components that make relatively stable small bubbles. A third type of contrast medium uses "hard" spheres filled with a gas. These contrast media are typically supplied as a powder that is mixed with a liquid. The goal is to suspend the spheres in the liquid without breaking them. Even though such spheres have a shell that is hard compared to a liquid, they are very small and relatively fragile. It is also possible for the solid particles themselves to act to scatter ultrasonic energy, but the acoustical properties of the solid spheres are not as different from liquid as those of a gas, so the difference in reflected energy is not as strong.

After mixing/preparation as described above, the contrast medium is drawn into a syringe or other container for injection into the patient. Typically, the fluid is injected into a vein in the arm of the patient. The blood dilutes and carries the contrast medium throughout the body, including to the area of the body being imaged.

It is becoming more common for a microprocessor controlled powered injector to be used for injecting the contrast medium to maintain a consistent flow over a long time, thereby providing a consistent amount of contrast medium (number of particles) in the blood stream. If there are too few particles in a region of interest, for example, there is insufficient image contrast and the diagnosis cannot be made. If too many particles are present, too much energy is reflected, resulting in blooming or saturation of the ultrasound receiver.

Although a power injector can inject contrast medium at a constant flow rate, there should be a generally constant number of bubbles/particles per volume of fluid injected to provide a constant image contrast. Because a gas is significantly less dense than water and other liquids, however, gas bubbles will rise in a liquid. The rate of rise is related to the diameter of the gas bubble. This density difference is useful to quickly separate large bubbles created during the initial mixing. However, the small bubbles desired for image enhancement will also rise slowly. Solid particles, on the other hand, tend to settle or sink because most solids are denser than water. Many rninutes can elapse between the initial mixing of the contrast medium and the injection into the patient, and/or the injection itself may be several minutes in duration. Certain multi-component contrast media undergo significant separation after only a few minutes. If the concentration of particles changes over the volume of fluid, the image contrast will degrade.

The benefits of agitation of multi-component fluids to create, improve or maintain homogeneity via a number of techniques are discussed, for example, in U.S. Patent Application Serial No. 09/267,237, filed March 12, 1999, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. U.S. Patent Application Serial No. 09/267,237 discloses, for example, agitation of injection fluids by bulk motion of a container of the injection fluid, motion of a mixing element within the injection fluid and circulation of an injection fluid by pumping. Additionally, Published PCT Application No. WO 99/27981 discloses powered injectors designed to agitate contrast medium to, for example, maintain suspension of media such as ultrasound bubbles and provides representative studies of the efficacy of those powered injectors.

Nonetheless, it remains desirable to develop improved systems, devices and method to maintain multi-component contrast media in a mixed or homogeneous state throughout an injection proceeding.

SUMMARY OF THE INVENTION

The present invention provides generally, devices, systems and methods for creating and/or agitating a multi-component medium (for example, an ultrasound contrast medium, a medicant including a suspended agent etc.) suitable for injection into a patient.

In one aspect, the present invention provides an injector for use in connection with a syringe including a syringe plunger disposed therein to inject an injection fluid. The injector includes a linear drive member, which can, for example, include a first attachment member to form a connection with the syringe plunger. The injector also includes a rotational drive member to rotate an agitating mechanism of the syringe plunger. The rotational drive member can mechanically couple with the agitating mechanism. In one embodiment, the rotational drive member is positioned within the linear drive member and includes a second attachment member extending from the -front of the linear drive member to couple with the agitating mechanism. The rotational drive member can also couple with the agitation mechanism via electromagnetic energy. For example, a magnet can be rotationally positioned upon a forward end of the linear drive member to rotate the agitating mechanism via magnetic coupling therebetween.

The injector preferably further includes a control system to control the rotational drive member. The control system can, for example, control the rotational drive member in a non-continuous manner (for example, to pulse the rotation of the agitation mechanism).

another aspect, the present invention provides a plunger for use in a syringe to inject an injection fluid including: a base; at least one sealing member in connection with the base to form a seal with an interior wall of the syringe; and a pump mechanism positioned within a chamber in the base. The chamber can, for example, include an inlet port in fluid communication with the chamber and an outlet port in fluid communication with the chamber such that the pump mechanism can pump fluid in the syringe through the chamber to agitate fluid within the syringe.

h another aspect, the present invention provides a plunger for use in a syringe to inject an injection fluid including: a base; at least one sealing member in connection with the base to form a seal with an interior wall of the syringe; a pump mechanism positioned within a chamber in the base; and a front cover in connection with the base to contact the injection fluid. The front cover includes an inlet port in operative communication with the chamber and an outlet port in operative communication with the chamber such that the pump mechanism can pump fluid in the syringe through the chamber to agitate fluid within the syringe.

In another aspect, the present invention provides a plunger for use in a syringe to inject an injection fluid including: a base; at least one sealing member in connection with the base to form a seal with an interior wall of the syringe; and an impeller foπ-ning at least part of a forward section the plunger to contact and agitate the injection fluid.

In a further aspect, the present invention provides an injector system for injecting an injection fluid into a patient including an injector and a syringe. The injector includes: a linear drive member having a first attachment member to form a connection with the syringe plunger and a rotary drive member having a second attachment member to form a connection with a rotary shaft of the syringe plunger. The syringe is attachable to the injector and includes a plunger slidably disposed therein. The plunger includes a base, at least one sealing member in connection with the base to form a seal with an interior wall of the syringe, a rotary shaft extending through the base, and an agitation mechanism in operative connection with the rotary shaft.

The agitation mechanism can, for example, include an impeller to contact and agitate the injection fluid. Alternatively, the agitation mechanism can include a pump mechanism positioned within a chamber in the base as described above.

In another aspect, the present invention provides an injector system for injecting an injection fluid into a patient including an injector and a syringe. The injector includes: a linear drive member and a rotational drive member. The syringe is attachable to the injector and includes a plunger slidably disposed therein. The plunger includes: a base, at least one sealing member in connection with the base to form a seal with an interior wall of the syringe, and an agitation mechanism adapted to be rotated by the rotational drive member to agitate fluid within the syringe.

i still a further aspect, the present invention provides a method of agitating a fluid within a syringe including the steps: drawing the fluid into a chamber formed in a plunger of the syringe; and expelling the fluid from the chamber to agitate the fluid within the syringe. The fluid can, for example, be drawn into the chamber and expelled from the chamber in a non-continuous (for example, pulsed) manner. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a ront perspective view of one embodiment an injector system of the present invention.

Figure 2 A illustrates a side transparent or hidden line view of the injector system of Figure 1.

Figure 2B illustrates a side cross-sectional view of the syringe and plunger of Figure 2A.

Figure 2C illustrates a side cross-sectional view of the plunger of Figure 2A in a disassembled or exploded state.

Figure 2D illustrates a side cross-sectional view of the plunger of Figure 2A in a disassembled or exploded state in general alignment with the drive member of the powered injector.

Figure 2E illustrates a side cross-sectional view of an embodiment of an injector system of the present invention in which an impeller is driven by magnetic force via a magnetic drive positioned on the injector piston.

Figure 2F illustrates a side cross-sectional view of an embodiment of an injector system of the present invention in which an impeller is driven by magnetic force via a magnetic drive positioned around the circumference of the syringe.

Figure 2G illustrates graphically a study of bubble concentration over time for a fluid injected -from the syringe of Figure 2 A with no agitation.

Figure 2H illustrates graphically a study of bubble concentration over time for a fluid injected from the syringe of Figure 2A in which the impeller was pulsed to agitate the fluid within the syringe.

Figure 3A illustrates a side cross-sectional view of an embodiment of another embodiment of an inj ector system of the present invention. Figure 3B illustrates a front view of the plunger of Figure 3 A.

Figure 3C illustrates graphically a study of bubble concentration over time for a fluid injected -from the syringe of Figure 3 A in which the impeller/pump mechanism of Figure 3 A was pulsed to agitate the fluid within the syringe.

DETAILED DESCRIPTION OF THE INVENTION

In several embodiments, the present invention provides devices, systems and methods to facilitate or to improve the initial creation and or mixing of a multi- component injection fluid such as an ultrasound contrast medium and to agitate the contrast medium to maintain a relatively uniform distribution of the contrast enhancing agents (for example, bubbles or particles) throughout the liquid contrast medium prior to and/or during an injection procedure. The present invention is, additionally, applicable generally to multi-component fluids wherein the fluid components are not totally miscible and there is a tendency for the components to separate over time (for example, because of differences in density). The present invention is also applicable to miscible or dissolvable materials during the initial preparation phase when a uniform mixture has not yet been created.

Figure 1 illustrates one embodiment of an injector system 5 of the present invention, which includes a powered injector 10 and a syringe 20 for injection of, for example, a contrast medium, hj ector housing 30 of injector 10 preferably includes a first drive member or piston 40 therem that cooperates with a syringe plunger slidably disposed in syringe 20 to inject a fluid from the interior of syringe 20 into a patient.

As used herein to describe, for example, injector 10 and syringe 20, the terms "axial" or "axially" refer generally to, for example, an axis such as axis A' (see Figure 1) around which syringe 20 is preferably formed (although not necessarily symmetrically therearound) and to directions collinear with or parallel to axis A' . The terms "proximal" or "rearward" refer generally to an axial or a longitudinal direction toward the end of injector housing 30 opposite the end to which syringe 20 is mounted. The terms "distal" or "forward" refer generally to an axial or a longitudinal direction toward a syringe tip 26 of syringe 20 (-from which pressurized fluid exits syringe 20). The term "radial" refers generally to a direction normal to an axis such as axis A'.

As illustrated in Figure 1, syringe 20 is preferably con-nectible to injector 10 via an interface 60, which can be removably or permanently mounted on the injector 10 for retaining syringe 20 or an adapter or intermediate connector thereon. The syringe or adapter is, for example, releasably or removably connected to the interface 60 through a bayonet connection. To implement the bayonet connection, interface 60 preferably includes two retaining flanges 68 formed around an opening 62 therein. Syringe 20 preferably includes two complementary mounting flanges 22 formed thereon for mating with the retaining flanges 68. Further, syringe 20 may include a sealing or biasing flange 28 for abutting a peripheral, front edge of interface 60 when syringe 20 is mounted thereon.

To attach syringe 20 to injector 10, syringe 20 is inserted into interface 60 (see Arrow A in Figure IB) with mounting flanges 22 aligned with cooperating slots 66 on interface 60. Syringe 20 is then rotated (see Arrow B) to engage mounting flanges 22 with retaining flanges 68. A similar bayonet apparatus for front-loading a syringe or adapter onto an injector is disclosed in U.S. Patent No. 5,383,858, the disclosure of which is incorporated herein by reference.

Piston 40 is reciprocally mounted within injector 10 and is extendible through opening 62 in syringe interface 60. Piston 40 can, for example, include a piston flange or head 44 to assist in forming a connection with syringe plunger 100 (see, for example, Figure 2A). Piston flange 44 can, for example, engage a connection mechanism such as capture members 140a and 140b on the rear of syringe plunger 100 (illustrated, for example, in Figures 2 A through 2C) as, for example, described in U.S. Patent No. 5,383,858. As clear to one skilled in the art, however, many types of cooperating connection mechanisms can be used to connect an injector drive member to a syringe plunger.

After securely attaching syringe 20 to injector 10, advancing piston 40 in a forward direction will apply a motive force to plunger 100 to advance plunger 100 forward within syringe 20, thereby forcing the contents of syringe 20 out of syringe tip 26 into the fluid path to the patient. Retracting piston 40 in a rearward direction will cause plunger 100 to move rearward within syringe 20, thereby drawing fluid into syringe 20.

Piston 40 also includes a rotary drive coupling 50 that is in operative connection with, for example, a gear motor 54 positioned with piston 40 (see, for example, Figure 2D) to rotate drive coupling 50 in a controlled manner, hi the embodiment of Figures 2A through 2D, rotary drive coupling 50 cooperates with an impeller shaft 110 of rotatably disposed within plunger 100. The forward end of impeller shaft 110 has attached thereto an impeller 120, which contacts the injection fluid within syringe 20 and is suitable to create agitating mixing of a multi-component fluid within syringe 20. Impeller 120 can, for example, include a plurality of vanes 122, which assist in imparting motion to surrounding fluid when impeller 120 is rotated. Vanes 122 can, for example, be formed to be flexible, hingable and/or bendable to deform or to displace upon contacting a forward surface of syringe 20 to facilitate injection of all fluid from syringe 20 and to minimize waste of such fluid. Drive coupling 50 can, for example, include a passage 52, that cooperates with a corresponding coupling 112 on a rear end of impeller shaft 110.

As illustrated, for example, in Figures 2C and 2D, syringe plunger 100 includes a base or frame 130 having a passage or channel 132 through which impeller shaft 110 passes to connect to drive coupling 50. Drive coupling 50 seats in a widened area 134 of passage 132. A rear portion of plunger 100 includes L-shaped capture members 140a and 140b, which form a secure connection with piston flange 44 as described above. Plunger base 130 also includes a sealing section to create a seal with the inner wall of the barrel of syringe 100. The sealing section can, for example, include at least one sealing member 150a such as an O-ring that forms a seal with the inner wall of the syringe barrel. Sealing member 150a can, for example, be seated in an annular groove or seating 152a formed in plunger base 130. hi the embodiment of Figures 2A through 2E, two sealing member 150a and 150b are seated in annular grooves 152a and 152b, respectively. A sealing member 160 such as an O-ring is preferably provided to form a seal between impeller shaft 110 and passage 132. Sealing members 150a, 150b and 160 assist in preventing injection fluid in the interior of syringe 20 from passing to the rear of plunger 100. Impeller 120 forms a front or forward section or cover of plunger 120 and is advanced and refracted with plunger 100.

In the embodiment of Figures 2A through 2D, rotational motion is imparted to impeller 120 via mechanical coupling of an impeller shaft 110 extending through plunger 100 to rotational drive member 54. Figure 2E illustrates an embodiment of an injection system in which an impeller 120a (including vanes 122a) is rotatably attached to a plunger 100a slidable disposed within syringe 20a. In the embodiment of Figure 2E, rotational motion is imparted to impeller 120a, which includes a magnetic component, via magnetic coupling with a drive magnet 50a disposed on a forward end of piston 40a. Drive magnet 50a can, for example, be rotated hi a controlled manner (as described further below), via a rotational drive member disposed within piston 40a.

Figure 2E illustrates an alternative embodiment of an injection system in which an impeller 120b (including vanes 122b) is rotatably attached to a plunger 100b slidable disposed within syringe 20b. h the embodiment of Figure 2F, rotational motion is imparted to impeller 120b, which includes a magnetic component, via magnetic coupling with a drive magnet 50b disposed around the circumference of syringe 20b. Drive magnets 50a and 50b can be rotated to impart rotational motion to impellers 120a and 120b, respectively, or such motion can, for example, be induced via appropriate control (as known in the electromagnet arts) of a series of electromagnets comprising drive magnet 50a and or drive magnet 50b.

As discussed above, injector 10 includes a motor 54 positioned with piston 40, which is operable to rotate impeller shaft 110 via intervening rotary drive coupling 50. Motor 54 can include a controller 58 (see, for example, Figure 2D) to control, for example, whether rotation of impeller shaft 110/impeller 120 continuous in a single direction or the rotational direction can be oscillatory. Moreover, the motion of impeller 120 (as well as impellers 120a or 120b) can be pulsed in an on/off cycle as known in the motor control arts. Such pulsing of motion of impeller 120 can, for example, provide sufficient agitation while -minimizing damage to bubbles or other contrast agents that can result from impeller motion in certain media. In addition, the rate, duration and/or dwell period of activation (in, for example an on/off or pulse cycle) of impeller 120 can be controlled in coordination with the operation of the injection (for example, it may be advantageous to resuspend the contrast agent only just before and/or during an injection to enhance agent life. Controller 58 can, for example, be in operative communication with the data input system(s) 200 of injector 10 as well as the other control system(s) 210 of injector 10.

Moreover, the rotation of impeller shaft 110/impeller 120 can be controlled as a function of the position of plunger 100 in syringe 20 and thus as a function of the volume of fluid remaining in syringe 20. h that regard, as the volume of fluid remaining in syringe 20 decreases (that is, as plunger 100 advances forward to inject fluid from syringe 20), it can be desirable to, for example, decrease rotational speed and or to decrease dwell period of activation of a pulse cycle. In that regard, adequate mixing can be achieved through such reduced rotational speeds and/or shorter dwell periods in smaller volumes of fluid while reducing the potential for damage or destruction of contrast agent. Plunger position/remaining volume can, for example, be tracked by control system(s) 210 as known in the art (for example, via an encoder system and/or a potentiometer system).

Motion of impeller 120 can also be controlled as a function of the nature of the fluid within syringe 20. For example, fluid viscosity and/or stability of contrast agents (such as bubbles) can vary between contrast media. As a function of such parameters and others, impeller control can be optimized for a particular contrast medium.

Figures 2G and 2H illustrates the effectiveness of impeller 120. In the experimental setup used in collecting the data of Figure 2G and 2H, a spectral Doppler flow phantom was used to measure the relative return signal from diluted microbubbles flowing past a 4 MHz probe. The contrast agent used was LEVOVIST (available from Schering AG of Berlin, Germany) mixed at a concentration of 200 mg/ml, and was injected/delivered at a flow rate of 12 mL/min. Figure 2G illustrates a study of a bubble concentration over time for a syringe with no agitation, h Figure 2H impeller 120 was pulsed (that is, an on/off cycle of 10 seconds on and 1 minute off was used) to agitate the fluid within syringe 20. hi comparing Figures 2G and Figures 2H, it is seen that signal intensity remains relatively constant with agitation by impeller 120 whereas signal intensity varies substantially without agitation. The drop in return signal over time in the studies of Figure 2H is believed to be a result of normal bubble loss over time.

Figures 3 A through 3C illustrate another embodiment of an injection system 300 in which a multi-component injection fluid is agitated within a syringe 20. A plunger 400 is slidably disposed within syringe 20 as described above for plunger 100. Plunger 400 includes a base 410. A cover 420 (preferably, fabricated from an elastomeric material as known in the art) can be placed on or over a front or forward section of base 410. Forward cover 420 can, for example, include a radially inward projecting flange 422 which seats in an annular grove 412 formed in base 410. Base 410, further includes a chamber 430 in which a pumping mechanism is preferably disposed. In general, any type of pump mechanism (for example, linear displacement pumps, gear pumps, impeller pumps etc.) can be disposed within chamber 430. For example, base 410 can include a passage or channel 440 through which a pump drive shaft 450 can extend to connect to a rotary drive member 50' on the forward end of injector drive member or piston 40. Rotary drive member 50' can be powered by motor 54 as described above. In the embodiment of Figures 3A through 3C, rotary drive shaft 450 includes a channel or groove 452 which seats a forward extending element 52' of rotary drive member 50'. An O-ring 460 can be seated in base 410 to surround shaft 450 to prevent leakage of injection fluid.

Rotation of shaft 450 by drive member 50' causes rotation of an impeller mechanism including flexible vanes 460a, 460b ... within chamber 430. Rotation of the impeller mechanism draws injection fluid into chamber 430 through a first (inlet) port 470 in base 410 which is in general alignment and the fluid connection with first (inlet) port 424 formed in cover 420. Injection fluid leaves chamber 430 via a second (outlet) port (not shown in Figure 3A but generally identical in form to inlet 470) formed in base 410. The chamber outlet is in general alignment and fluid connection with a second (outlet) port 426 formed in cover 420. Thus, rotation of shaft 450 and the impeller mechanism connected to the forward end thereof results in circulation of multi- component injection fluid within syringe 20 and results in agitation thereof.

In general, the rate of flow of fluid through chamber 430 via inlet port 424 and outlet port 426 is controlled by the rate of rotation of shaft 450. As discussed above in connection with impeller shaft 110, the direction and angular velocity of shaft 450 can, for example, be controlled through use of an encoder or other controller 58 in operative connection with motor 54. The rotation can, for example, be made continuous in a single direction or the rotational direction can be oscillatory. Changing direction of the rotation of shaft 450 causes inlet ports describe about to function as outlet ports, while the outlet ports described above function as inlet ports. Moreover, the rate, duration and/or dwell period of activation motor 54 can be controlled in coordination with the operation of the injection (for example, it may be advantageous to resuspend the contrast agent only just before and/or during an injection to enhance agent life.

Existing powered injectors including a drive member such as piston 40 are readily retrofitted with a rotary drive member such as motor 54. Thus, existing powered injectors are easily provided with the ability to agitate multi-component fluids as described in the present invention.

As described above in connection with impellers 120a and 120b of plungers 100a and 100b, respectively, the pump mechanism of plunger 400 need not be driven via a mechanical coupling, h that regard, an electromagnetic coupling as describe above can be used.

A comparison of Figures 2G and 3C illustrates the effectiveness of impeller 120.

In the experimental setup used in collecting the data of Figure 3C, a spectral Doppler flow phantom was used to measure the relative return signal from diluted microbubbles flowing past a 4 MHz probe as described above. The contrast agent used was once again LEVOVIST mixed at a concentration of 200 mg/ml. The contrast agent was injected/delivered at a flow rate of 12 mL/min. hi Figure 3 C, the pump/impeller mechanism of plunger 400 was pulsed (with a pulse or on/off cycle of 10 seconds on and 1 minute off) to agitate the fluid within syringe 20. hi comparing Figures 2G and Figures 3C, it is seen that signal intensity remains relatively constant with agitation by the impeller mechanism whereas signal intensity varies substantially without agitation. The drop in return signal over time in the studies of Figure 3C is believed to be a result of normal bubble loss over time.

Although the present invention has been described in detail in connection with the above embodiments and/or examples, it is to be understood that such detail is solely for that purpose and that variations can be made by those skilled in the art without departing from the spirit of the invention except as it may be limited by the following claims.

Claims

WHAT IS CLAIMED IS:

1. An injector for use in connection with a syringe comprising a plunger disposed therein, the injector comprising:

a linear drive member having a first attachment member to form a comiection with the plunger; and

a rotational drive member to rotate an agitating mechanism of the plunger.

2. The injector of Claim 1 wherein the rotational drive member mechanically couples with the agitating mechanism.

3. The injector of Claim 2 wherein the rotational drive member is positioned within the linear drive member and includes a second attachment member extending from the front of the linear drive member to couple with the agitating mechanism.

4. The injector of Claim 1 wherein the rotational drive member couples with the agitation mechanism via electromagnetic energy.

5. The injector of Claim 1, further comprising a control system to control the rotational drive member.

6. The injector of Claim 5 wherein the control system is operable to control the rotational drive member to pulse the rotation of the agitation mechanism.

7. A plunger for use in a syringe to inject an injection fluid, the plunger comprising:

a base defining a chamber;

at least one sealing member in connection with the base to form a seal with an interior wall of the syringe; and

a pump mechanism positioned within the chamber in the base, the chamber comprising an inlet port in fluid communication with the chamber and an outlet port in fluid communication with the chamber such that the pump mechanism can pump fluid in the syringe through the chamber to agitate fluid within the syringe.

8. A plunger for use in a syringe to inject an injection fluid, the plunger comprising:

a base defining a chamber;

at least one sealing member in connection with the base to form a seal with an interior wall of the syringe;

a pump mechanism positioned within the chamber in the base; and

a front cover in connection with the base to contact the injection fluid, the front cover comprising an inlet port in operative communication with the chamber and an outlet port in operative communication with the chamber such that the pump mechanism can pump fluid in the syringe through the chamber to agitate fluid within the syringe.

9. A plunger for use in a syringe to inject an injection fluid, the plunger comprising:

a base;

an impeller forming at least part of a forward section of the plunger to contact and agitate the injection fluid.

10. An injector system for injecting a fluid into a patient, the injector system comprising:

an injector comprising:

a linear drive member having a first attachment member to form a connection with a syringe plunger; and a rotary drive member having a second attachment member to form a connection with a rotary shaft of the syringe plunger; and

a syringe operable to be attached to the injector, the syringe comprising a plunger slidably disposed therein, the plunger comprising:

a base;

a rotary shaft extending through the base; and

an agitation mechanism in operative connection with the rotary shaft.

11. The injector system of Claim 10 wherein the agitation mechanism comprises an impeller to contact and agitate the injection fluid.

12. The injector system of Claim 10 wherein the agitation mechanism comprises a pump mechanism positioned within a chamber defined in the base, the pump mechanism being in operative connection with the rotary shaft, the chamber comprising an inlet port in fluid communication with the chamber and an outlet port in fluid communication with the chamber.

13. The injector system of Claim 10 wherein the plunger further comprises a chamber formed in the base and the agitation mechanism includes a pump mechanism in operative connection with the rotary shaft; the plunger further comprising a front cover in connection with the base to contact the injection fluid, the front cover comprising an inlet port in operative communication with the chamber and an outlet port in operative communication with the chamber.

14. An injector system for injecting a fluid into a patient, the injector system comprising:

an injector comprising: a linear drive member; and

a rotational drive member; and.

a base;

an agitation mechanism adapted to be rotated by the rotational drive member to agitate fluid within the syringe.

15. A method of agitating a fluid within a syringe, the method comprising:

drawing the fluid into a chamber formed in a plunger of the syringe; and

expelling the fluid from the chamber to agitate the fluid within the syringe.

16. The method of Claim 15 wherein the fluid is drawn into the chamber and expelled from the chamber in a non-continuous manner.