WO2004039434A2

WO2004039434A2 - Method and apparatus for sequential delivery of multiple injectable substances stored in a prefilled syringe

Info

Publication number: WO2004039434A2
Application number: PCT/US2003/034842
Authority: WO
Inventors: Kyongtae T. Bae
Original assignee: Bae Kyongtae T
Priority date: 2002-10-31
Filing date: 2003-10-30
Publication date: 2004-05-13
Also published as: US6866653B2; AU2003290566A1; US20040097875A1; WO2004039434A3; WO2004039434B1; AU2003290566A8

Abstract

A syringe (12) capable of injecting two substances (142, 152) sequentially is provided. The syringe (120) has first (140) and second (150) chambers capable of separately storing a contents of the syringe (120) before and during injection. The syringe (120) has an outlet (122) through which the contents stored in the first (140) and second chamber (150) flow during injection. After completing injection of the contents stored in the first chamber (140), the second chamber (150) is aligned with the outlet (122) to allow injection of the contents stored in the second chamber (150).

Description

Method and Apparatus for Sequential Delivery of Multiple Injectable Substances Stored in a Prefilled Syringe

FIELD OF THE INVENTION

This invention refers to a syringe, and more specifically, to a syringe used for the sequential administration of two different injectable substances which are stored in separate chambers in the syringe.

BACKGROUND OF THE INVENTION

Computed tomography (CT) is a widespread diagnostic imaging method which measures the x-ray attenuation coefficient of matter. This x-ray attenuation coefficient is depicted in terms of Hounsefield Units. During a CT scan, a collimated X-ray beam is directed on the patient and the attenuated remnant radiation is measured by a detector whose response is transmitted to a computer. The computer considers the location of the patient and the spatial relationship of the x-ray beam to the region of interest and analyzes the signal from the detector so that a visual image of the region of interest can be reconstructed and displayed on a monitor. The image can then be viewed or stored for later evaluation.

Hounsefields Units reflect the relative absorption of the CT x-rays by matter, where the absorption is related to the atomic number, electron density, physical thickness of the matter, and the energy spectrum of the x-rays. Because of the similarity in electron density of various tissues in the body, CT scans sometimes result in poor imaging. In an attempt to obtain better results in such circumstances, a contrast agent, such as iodine, can be injected in the patent's blood stream to change the relative radio-density of the tissues, and improve the overall diagnostic capabilities of the procedure.

In addition to CT, magnetic resonance imaging (MRI) is a clinically important medical imaging modality because of its exceptional soft-tissue contrast. MRI exploits the existence of induced nuclear magnetism in the patient body. The magnetic resonance signals from water and the hydrogen atoms in fat are mapped according to their location within the patient so that the internal organs of a patient can be imaged without the use of ionizing radiation. Since its development nearly 30 years ago, MRI has become an invaluable medical imaging modality. Just like CT, contrast enhancement is extremely valuable in MRI for the visualization of normal tissue as well as the diagnosis of soft tissue diseases. Although there is an intrinsic contrast between a lesion and surrounding tissue in MRI, it is critical to selectively enhance the pathology or the structure of interest by administering a contrast agent. The most common agent used in MRI is Gadolinium, which can dramatically improve the conspicuity of the lesion and the image quality, particularly in magnetic resonance angiography.

The volume of Gadolinium used in a typical MRI procedure is usually around 20 cc, which is one-fifth of the amount of iodonated contrast used in a typical CT procedure. Because of this small volume, the relative amount of Gadolinium remaining in an injection tubing after completion of the injection is substantial, and to prevent waste, it is important to completely inject any Gadolinium remaining in the tubing at the completion of injection.

Contast agents may be administered either manually through hand injection of a syringe or automatically through the use of power injection equipment, which automatically injects the syringe. Several manufacturers, including Mallinckrodt Medical Inc. and MedRad Inc., produce a wide variety of power injectors for use in both CT and MR procedures. These power injectors may be either a single barrel style for injection of one syringe or double barrel style for injection of two syringes, although the single barrel style tends to be more commonly used.

Contrast agents are typically available in a bottle and are drawn into a syringe immediately prior to use in either manual or power injection imaging procedures. In applications where a relatively small volume of contrast agent is used, such as in a MR imaging procedure using Gadolinium, injection of the contrast agent may be performed by manual injection with a common syringe with injection tubing and an angiocatheter placed in the arm. In other applications, the syringe may be manually prepared for use in a power injector. As with any manual procedure, manual preparation of syringes involves multiple steps that are time-consuming and associated with potential contamination problems and dosing errors. To alleviate the problems inherent in manually preparing syringes of contrast agent, some suppliers provide contrast agents in prefilled syringes that can be used in either manual or power injection procedures. The prefilled syringe is gaining wide acceptance because it can reduce the complications and the number of steps previously associated with using bottled contrast agents, and a recent survey by the American Society of Radiologic Technologists reported that using a prefilled syringe in power injection equipment resulted in improved efficiency and quality of service, and less wasted contrast agent.

In CT and MR imaging procedures, the injection of a contrast agents maybe followed by the injection of a saline solution, which is commonly referred to as a saline flush or saline chase. The saline injection has several advantages in that it reduces the amount of contrast agent used and prevents waste. Previously, when planning an imaging procedure, the amount of contrast agent to be injected had to be increased to compensate for the amount of contrast agent left in the injection tubing at the completion of the procedure between the syringe and the patient vascular access injection site. Ordinarily, this amount of contrast agent is discarded along with the injection tubing at the end of the procedure. However, by using the saline flush, almost all of the contrast agent in the syringe can be used because the contrast agent that remains in the injection tubing between the injector and the patient vascular access injection site is injected into the body with the saline flush. The saline flush is also beneficial because it provides a final push and continuous steady flow of the contrast agent that is slowly flowing in the peripheral blood stream at the tail end of the injection, thereby improving efficient use and diagnostic contribution of the contrast agent that is already injected into the body. The saline flush also disperses the contrast agent accrued in the central venous structures at the tail end of the injection to reduce associated artifact at the injection site.

Despite its known benefits, the injection of a saline bolus following the contrast agent is not commonly practiced. Most often, the saline flush injection is administered by using a double barrel power injector that can inject two syringes independently and sequentially. In the double barrel injector, one of the injector barrels is used for injecting the contrast agent and the other injector barrel is used for injecting the saline flush solution. In a double barrel power injector set-up, each of the syringes in the injector has a tubing that leads from the syringe to a one-way valve and then to a Y-adapter which then leads to a common injection catheter. The double barrel power injector allows for a precise amount of contrast agent to be injected from the first syringe at a steady and continuous injection rate followed immediately by the injection of saline from the other syringe. Without a double- barrel injector, injection may be performed manually, but a manual injection cannot provide the precise injection rate required to produce good-quality images, particularly when CT contrast agent is injected, which tends to be very viscous.

Additionally, with manual injection, it is often difficult to inject the saline flush rapidly and immediately after injection of the contrast agent without any gaps in the bolus. Because most power injectors are of the single barrel style, a saline flush is typically not performed. Thus, to provide the benefits of the saline injection after the injection of the contrast agent, what is needed is a single pre-filled syringe that stores both substances separately and can inject them sequentially either manually or through existing single barrel power injection equipment. In the medical field, a dual chamber prefilled syringe has been commonly used to separately store two substances, usually a medical component and a vehicle. However, these syringes do not allow for sequential injection of the substance, but provide a thorough mixing of the substances into a homogeneous injection liquid before injection. In the syringes described in U.S. Pat. Nos. 5,788,670 and 5,865,799, the two substances are mixed within the prefilled syringe and then directly injected from the prefilled syringe. Typically, the dual chamber prefilled syringe is formed of a single syringe barrel made of glass or plastic with an end plunger and rod positioned opposite of the syringe head. An intermediate plunger is positioned in the barrel of the syringe to divide the barrel of the syringe and create two separate chambers in the syringe for separately storing the substances before injection. When injecting the contents of the syringe, the plunger rod connected to the plunger is moved forward to the direction of the syringe head thereby forcing the intermediate plunger through the syringe until it reaches a bypass positioned in the mid section of the syringe barrel, which allows the substance in the second chamber flow into the first chamber where the two components are then subsequently mixed and injected by the continued movement of the plunger and plunger rod. While conventional syringes of this type are effective for mixing two substances immediately before injection to reduce the risk of cross contamination and to allow effective packaging of the substances, conventional syringes of this type do not allow for sequential injection of the components in the syringe so as to allow their use in an imaging application.

What is needed is a syringe capable of sequentially injecting two substances from one syringe. Such a syringe would be readily useable in imaging applications as the syringe would be preferably pre-filled with a desired contrast agent and a saline solution to provide in-line flushing in the injection tubing to prevent waste of the contrast agent even when small volumes of contrast agent are used. Such a syringe would be readily adaptable to fit in existing power injection equipment such as the commonly used single barrel injector described previously or a double barrel injector where only one side of the injector need be used. By providing the flush solution in line with the contrast agent, all of the contrast agent in the tube can be used instead of discarding the residual contrast agent that is ordinarily left over in the injection tubing in the double barrel injector between the syringe head and the "Y" connector or in the single barrel injector between the syringe head and the patient injection site. Such a syringe would allow the use of a saline flush with the single barrel injector to achieve the clinical benefits described above that are ordinarily only achieved through the use of the less common double barrel injector. SUMMARY OF THE INVENTION

Among the aspects of the present invention is the provision of dual chamber syringe that is adapted to provide sequential injection of two substances from one syringe. Preferably, the syringe has a first chamber for holding a first fluid and a second chamber separate from the first chamber for holding a second fluid. An outlet is provided though which the fluids stored in the first and second chambers flow during injection. During injection, the outlet is first aligned with the first chamber to allow the first chamber fluid to be injected from the syringe after which the outlet is then aligned with the second chamber to allow the second chamber fluid to be injected.

Preferably, the outlet of the syringe is on an end of the syringe and the syringe has a moveable plunger that is connected to a plunger rod at an end opposite the outlet. The plunger rod may be pushed forward, thereby advancing the first chamber fluid and the second chamber fluid through the syringe. This action of the plunger allows the first fluid to be injected first, and then allows the second fluid to be injected only after completion of the injection of the first fluid. A syringe constructed in accordance with this aspect of the invention may used in an imaging application by placing a contrast agent in the first chamber and a saline solution in the second chamber. By forward advancement of the plunger, the saline solution pushes the contrast agent into patient injection site and then flows to the patient injection site to clear the injection line to provide the benefits described above.

In one aspect of the invention, the first and second chambers and the fluids stored therein are separated by a movable intermediate plunger or disc disposed within the syringe interior. During injection, the disc sealingly engages the syringe interior to separate the chambers and the respective fluids. As the disc moves through the tube interior, the disc acts on the first chamber fluid to inject the first chamber fluid. When the first fluid is injected, the disc disengages from the syringe interior to align the outlet with the second chamber to allow injection of the second fluid. Preferably, the outlet of the syringe is configured to engage the disc as its travels to the outlet thereby disengaging the disc from the syringe interior when the first fluid has been injected to allow alignment of the outlet with the second chamber and sequential injection of the first and second fluids.

In another aspect of the invention, the second chamber may be provided via a sealed bag disposed in the syringe and the second fluid may be contained the bag thereby allowing the separate storage of the first and second fluids in the syringe. In accordance with this aspect of the invention, the outlet is configured to pierce the bag after the first fluid has been injected thereby releasing the second fluid from the bag and allowing the second fluid to be injected sequentially after the first fluid.

Other aspects and provisions of the invention will become apparent upon further review of the drawings figures showing different embodiments of syringes of the present invention and in the detailed description thereof which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a longitudinal cross-sectional view of a syringe of the present invention; Fig. 1 A is a transverse cross-sectional view of the syringe along lines A-A of

Fig. 1;

Fig. IB is a transverse cross-sectional view of the syringe along lines B-B of Fig. 1; Fig. 1C is a transverse cross-sectional view of the syringe along lines C-C of

Fig. 1;

Fig. ID is a transverse cross-sectional view of the syringe along lines D-D of Fig. 1; Fig. IE is a transverse cross-sectional view of the syringe along lines E-E of

Fig. 1;

Figs. 2A-C are longitudinal cross-sectional views of the syringe of Fig 1. at intermediate steps of injection;

Fig. 3 is a longitudinal cross-sectional view of an alternate embodiment of the syringe of Fig. 1;

Fig. 3 A is a transverse cross-sectional view of the syringe along lines A-A of Fig. 3;

Fig. 3B is a transverse cross-sectional view of the syringe along lines B-B of Fig. 3; Fig. 3C is a transverse cross-sectional view of the syringe along lines C-C of

Fig. 3;

Fig. 3D is a transverse cross-sectional view of the syringe along lines D-D of Fig. 3;

Fig. 3E is a transverse cross-sectional view of the syringe along lines E-E of Fig. 3;

Figs. 4A-C are longitudinal cross-sectional views of the syringe of Fig. 3 at intermediate steps of injection;

Fig. 5 is a longitudinal cross-sectional view of an alternate embodiment of the syringe of Fig. 1; Fig. 5 A is a transverse cross-sectional view of the syringe along lines A-A of

Fig. 5;

Fig. 5B is a transverse cross-sectional view of the syringe along lines B-B of Fig. 5;

Fig. 5C is a transverse cross-sectional view of the syringe along lines C-C of Fig. 5;

Fig. 5D is a transverse cross-sectional view of the syringe along lines D-D of Fig. 5; Fig. 5E is a transverse cross-sectional view of the syringe along lines E-E of Fig. 5;

Figs. 6A-C are longitudinal cross-sectional views of the syringe of Fig. 5 at intermediate steps of injection; Fig. 7 is a longitudinal cross-sectional view of an alternate embodiment of the syringe of Fig. 1;

Fig. 7 A is a transverse cross-sectional view of the syringe along lines A-A of Fig. 7;

Fig. 7B is a transverse cross-sectional view of the syringe along lines B-B of Fig. 7;

Fig. 7C is a transverse cross-sectional view of the syringe along lines C-C of Fig. 7;

Fig. 7D is a transverse cross-sectional view of the syringe along lines D-D of Fig. 7; Fig. 7E is a transverse cross-sectional view of the syringe along lines E-E of

Fig. 7; and

Figs. 8A-C are longitudinal cross-sectional views of the syringe of Fig. 7 at intermediate steps of injection.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Mode l Figure 1, 1 A- IE and 2A-2C show one embodiment of a syringe 120 of the present invention, which will be referred to hereinafter as Mode I. The syringe of Mode I is a cylindrical tube preferably having an outlet 122 at one end and a plunger 124 at an end opposite the outlet. The plunger 124 is sealing engaged with an interior 126 of the tube to allow it to be moved along a length the tube toward the outlet 122 and to provide the necessary pressure to inject a contents of the syringe from the outlet, as will be described in greater detail below. A rod 128 may be attached to the rear plunger 124 to move the rear plunger along the entire length of the tube.

An intermediate plunger or disc 130 is provided in the tube interior to divide the tube into a first chamber 140 for holding a first contents 142 and a second chamber 150 for holding a second contents 152. The first chamber 140 is defined by the space in the tube interior between the disc 130 and the outlet 122 and the second chamber 150 is defined by the space in the tube interior between the disc and the rear plunger 124. The disc 130 sealingly engages with the tube interior 126 to prevent mixing of the chambers' contents or fluids 142,152 when the syringe 120 is being stored and also when the first chamber is being compressed and the first chamber contents 142 is being injected. As will be described in greater detail below, when the syringe is filled, the disc 130 moves along a portion of the length of the tube through the action of the plunger 124 acting on the second chamber contents 152. This in turn allows the disc 130 to push on the first chamber contents 142 to provide injection while at the same time preventing the mixing of the chambers' contents 142,152. Preferably, the outlet 122 and the first and second chambers 140,150 are aligned axially along a center axis 160-160 of the tube, and preferably, the plunger 124 and the disc 130 are aligned axially with the outlet and the first and second chambers such that the disc and plunger act directly on the first and second chambers and their contents, respectively.

Preferably, the Mode I syringe 120 is formed with a radially enlarged portion 170 or vestibule adjacent the outlet 122. The radially enlarged portion 170 may be formed as a protruding ring at the syringe outlet such that an exterior surface 172 of the tube has a larger outer diameter at the radially enlarged portion or the radially enlarged portion may be formed within a wall thickness of the tube thereby allowing the tube exterior to have a uniform outer diameter. Preferably, the radially enlarged portion 170 extends completely around the tube so as to accommodate a baffle 180 at the outlet 122 of the syringe, as will be described below. Preferably, the baffle 180 is disposed within the radially enlarged portion 170 and provides a means of preventing the disc 130 from obstructing the outlet 122 when the disc moves towards the outlet after injection of the first chamber contents 142. Preferably, the baffle 180 allows the second chamber contents 152 to flow from the second chamber 150 to the outlet 122 when the disc 130 is moved towards the outlet into the radially enlarged portion 170 of the syringe. As shown in Figs. 1B-1C, the baffle 180 may be formed by layers 182 of material having different geometric cross sections which create channels 184 to the outlet 122 when stacked axially. The layer 182 shown in Fig. ID has notches 186 around a bore 188. Thus, when the disc 130 moves into the radially enlarged portion 170 and the bore 188 receives the disc, the notches 186 provided in the layers 182 of Figs. 1B-1C allow the second chamber contents 152 to flow around the disc in the channels 184 to the outlet 122. For example, in the arrangement shown in Figs IB- ID, the layers 182 create a baffle with four channels 184 that lead to the outlet 122 when the disc is received in the baffle bore 188. Preferably, the radially enlarged portion 170 is sized to receive each of the layers 182 comprising the baffle 180 and provide a smooth transition for the disc 130 when it moves from the tube interior 126 to the baffle bore 188.

Refeπing to Figs. 2A-2C which show the operation of the Mode I syringe 120, two different injectable substances 142,152 are stored separately in the first and second chambers 140,150 of the syringe. With the plunger 124 pushed forward, the contents of the first chamber 140 is injected first through the outlet 122 through the action of the plunger acting on the second chamber contents 152 which in turn acts on the disc 130 and the first chamber contents 142. Following the completion of the injection of the first chamber contents 142, the disc 130 is received in the baffle bore 188 (Fig. 2C). However, the second chamber contents 152 continues to flow to the outlet 122 though the channels 184 formed between the disc 130 and the baffle 180 until the second chamber 150 is sufficiently compressed and the remaining second chamber contents is fully injected from the syringe. In this position, a portion of rear plunger 124 may also be received in the baffle bore 188. As shown in Fig. 2C, the rear plunger 124 preferably has its axial width or thickness dimensioned so that at the end of the injection with the plunger 124 against the disc 130, the radially enlarged portion 170 of the tube remains sealed at the rear opening of the syringe.

Mode II Figure 3, 3A-3E and 4A-4C show an alternate embodiment of a syringe 220 of the present invention, which will be referred to hereinafter as Mode II. The Mode II syringe 220 is also a cylindrical tube preferably having its outlet 222 at one end and its plunger 224 at the opposite end. The plunger 224 is sealingly engaged with the tube interior 226 and moves along the tube length toward the outlet 222 to provide the needed pressure to inject the syringe contents from the outlet. Preferably, the outlet 222 and the first and second chambers 240,250 are aligned axially along the center axis 260-260 of the tube, and preferably, the plunger 224 is aligned axially with the outlet and the first and second chambers such that the plunger acts directly on the second chamber and its contents. As in Mode I, the Mode II syringe has an intermediate movable plunger or disc 230 that is sealingly engaged with the tube interior 226 to define the first and second chambers 240,250 and to maintain the separation of the chambers' contents 242,252 during the storage and injection. The main body of the syringe has a radially enlarged portion 270 adjacent the outlet 222 at the front of the tube. Preferably, in Mode II, the radially enlarged portion 270 only extends around a portion of the tube and may be formed within the wall thickness of the tube to allow the tube to have a uniform outer diameter or as a protuberance such that the tube has an enlarged outer diameter in the area adjacent the outlet. Preferably, the radially enlarged portion 270 has a generally circular cross section with its center offset from the center axis of the tube (Fig. 3B).

Preferably, a baffle 280 is disposed in the radially enlarged portion 270 to engage the disc 230 and hold the disc away from the outlet 222 to prevent obstruction of the outlet and to allow the second chamber contents 252 to flow around the disc and to the outlet. As shown in Fig. 3C, the baffle 280 is formed by four rectangular members 282 which extend radially from the radially enlarged section 270 of the tube interior toward the tube center where the ends of the members 280 in the center of the tube are spaced from one another to provide an unobstructed path to the outlet 222. Referring to Figs. 4A-4C which show the operation of the Mode II syringe 220, forward motion of the rear plunger 224 pushes the second chamber contents 252 and the disc 230 through the tube interior, resulting in the injection of the first chamber contents 242. After completing injection of first chamber contents 242, the disc 230 enters the radially enlarged section 270. Because the diameter of the radially enlarged section 270 is greater than that of the disc 230, when the disc approaches the radially enlarged portion, the disc becomes disengaged from the tube interior 226 allowing the second chamber contents 252 to flow around the disc (Fig. 4B). The disc 230 then tends to become centered in the radially enlarged portion 270 from the flow of the second chamber contents 252 around the disc. As the disc 230 moves toward the outlet 222, the baffle 280 prevents the disc from completely obstructing the syringe outlet. The second chamber contents 252 continues to flow around the disc and the baffle rectangular members 282 to the outlet 222 until the second chamber contents is fully injected when the rear plunger 224 comes to rest against the disc. In this position, the rear plunger 224 has its width or thickness dimensioned so that at the end of the injection of the second chamber contents 252, the radially enlarged portion 270 of the tube interior remains sealed to the rear opening of the syringe (Fig. 4C).

Mode III Figs. 5, 5A-5E, and 6A-6C show an alternate embodiment of a syringe 320 of the present invention which will hereinafter be referred to as Mode III. Again, the overall construction of the Mode III syringe 320 is similar to that of Modes I and II described above. The disc 330 is sealingly engaged with the tube interior 326 to divide the tube into first and second chambers 340,350 while maintaining the separation of the chambers' contents 342,352 during the storage and injection.

Preferably, the first and second chambers 340,350 are aligned axially with the syringe outlet 322 along the center axis 360-360 of the syringe, and preferably, the disc 330 and the rear plunger 324 are aligned axially along the center axis of the syringe. The syringe 320 has its radially enlarged portion 370 formed adjacent the outlet 322 at the front of the tube. As with the Mode II syringe, the Mode III syringe preferably has its radially enlarged portion 370 that only extends around a portion of the tube. The radially enlarged portion 370 may be formed within the wall thickness of the tube to allow the tube to have a uniform outer diameter or the radially enlarged portion may be formed as a protuberance such that the tube has an enlarged outer diameter in the area adjacent the outlet 322. Preferably, the radially enlarged portion 370 has a generally circular cross section with its center offset from the center axis 360-360 of the tube (Fig. 5C). Preferably, centered within the radially enlarged portion 370, a protrusion 372 is provided that extends partially in a radial direction from the tube wall toward the tube interior. Preferably, the protrusion 372 has a relatively short arc length within the radially enlarged portion, as will become apparent from the description below. The radially enlarged section 370 is configured to allow the disc 330 to be tilted or partially rotated when the disc travels into the radially enlarged section and engages the protrusion 372.

Referring to Figs. 6A-6C which show the operation of the syringe of Mode III, forward motion of the rear plunger 324 pushes the second chamber contents 352 and the disc 330, resulting in the injection of the first chamber contents 342 (Fig. 6A). After the completion of the injection of the first chamber contents 342, the disc 330 enters the radially enlarged portion 370 and engages the protrusion 372 whereupon the disc is tilted by the continued forward motion of the rear plunger 324 and from the flow of the second chamber contents 352 to the outlet. The disc 330 becomes trapped in the radially enlarged portion 370, but because the disc is disengaged from the tube interior 326 as it is tilted or partially rotated, the second chamber contents 352 flows around the disc to the outlet 322 in the channels 384 created between the disc, the protrusion 372 and the radially enlarged portion. The second chamber contents 352 continues to flow around the disc until the second chamber contents is fully injected when the rear plunger 324 comes to rest against the disc. In this position, the rear plunger 324 has its width or thickness dimensioned so that at the end of the injection of the second chamber contents 352, the radially enlarged portion 370 of the tube interior remains sealed to the rear opening of the syringe (Fig. 6C).

Mode IV Figs. 7, 7A-7D, and 8A-8C show an alternate embodiment of a syringe 420 of the invention which will hereinafter be referred to as Mode IV. The Mode IV syringe 420 is a cylindrical tube preferably having its outlet 422 at one end and its plunger 424 at an end opposite the outlet. The plunger 424 is sealingly engaged with an interior 426 of the tube to allow it to be moved along a length the tube toward the outlet 422 and to provide the necessary pressure to inject a contents of the syringe from the outlet. In the Mode IV syringe 420, the outlet 422 is configured with a barb 432, the purpose of which will be described in greater detail below.

In the Mode IV syringe, a bag 450 is disposed in the tube interior 426 adjacent the rear plunger and filled with a contents 452. The structure of the bag divides the syringe into the first and second chambers 440,450 where a front wall 454 of the bag primarily applies a force on the first chamber 440 during injection of the first chamber contents 442. The bag 450 may be generally cylindrical in shape and generally conform to the tube interior 426 although it is not necessary that the bag sealingly engage the tube interior as some of the first chamber contents may flow around the bag to the rear plunger 424. In this way, the rear plunger 424 may act on the first chamber contents 442 directly, although the bag 450 and primarily its front wall 454 will also act on the first chamber 440 as the bag is guided through the tube by the rear plunger. The bag 450 may also be attached or adhered to the rear plunger 424 to ensure the bag remains aligned in the tube and to provide the consistent application of positive pressure by the rear plunger during injection. Preferably, the syringe outlet 422, the rear plunger 424 and the first chamber 440 are aligned axially with the center axis 460-460 of the syringe.

Referring to Figs. 8A-8C, operation of the syringe of Mode IV will be described. Preferably, the second chamber contents 452 is contained within the bag 450 and the remaining tube volume forms the first chamber 440 which is filled with the first chamber contents 442. Forward motion of the rear plunger 424 will push the bag 450 through the tube interior 426 thereby injecting the first chamber contents 442 (Fig. 8A). Preferably, two barbs 432 or other sharp protrusions are formed on an inner front wall of the syringe adjacent the outlet 422. At the completion of the injection of the first chamber contents 442, continued forward movement of the rear plunger 424 forces the front wall 454 of the bag against the barbs 432 thereby piercing the bag 450 and releasing the contents 452 of the bag or the second chamber. Continued forward motion of the rear plunger 424 compresses the bag 450 until the second chamber contents 452 is fully injected and the plunger stops as it butts against the protrusion and the front wall of the syringe (Fig. 8C).

As shown above, the syringe of the present invention provides an efficient vehicle for the administration of two injectable substances sequentially. In imaging applications, the syringe of the present invention may be used in existing power injector equipment without modification to the power injectors. Moreover, by providing the contrast agent and saline flush in a single syringe, the clinical benefits of the saline flush may be attained with the use of a single barrel injector thereby eliminating the need for providing the saline flush through the double barrel power injector. The syringe of the present invention minimizes the number of syringes used during an imaging procedure and allows for the effective use of the contrast agent. Additionally, the prefilled syringes of the present invention prevents the problems associated with the manual preparation of syringes, including cross contamination and improper dosing.

In view of the above, several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description and in the accompanying drawings shall be interpreted as illustrative and not in any limiting senses. The invention therefore shall be limited solely be the scope of the claims set forth below.

Claims

What is claimed is:

1. A syringe comprising: a first chamber being adapted to contain a first fluid in the syringe; a second chamber being adapted to contain a second fluid in the syringe, the second chamber being separate from the first chamber when the first and second chambers are filled with the respective first and second fluids; and an outlet through which the first and second fluids flow when the first and second fluids are injected from the syringe, the outlet being aligned in communication with the second chamber to allow the second fluid to flow through the outlet only after the first chamber has been emptied and the first fluid has been injected from the syringe.

2. The syringe of claim 1 wherein the second chamber comprises a bag and the outlet comprises a barb adapted to puncture the bag to release the second fluid from the bag when the first chamber has been emptied and the first fluid has been injected from the syringe.

3. The syringe of claim 1 wherein the outlet, first chamber and second chamber are aligned axially along a center axis of the syringe with the first chamber being positioned between the outlet and the second chamber.

4. The syringe of claim 1 wherein the outlet is on an end of the syringe, and the syringe further comprises a plunger sealingly engaged with the syringe at an end of the syringe opposite of the outlet, the plunger acts on the second fluid in the second chamber to inject the first and second fluids in sequence through the outlet when the plunger is moved toward the outlet during injection.

5. The syringe of claim 1 wherein the first and second chambers are separated by a disc adapted to be moved within an interior of the syringe along a length of the syringe in a manner such that the disc is sealingly engaged with the syringe interior during injection of the first fluid and thereafter disengaged from the syringe interior whereby the outlet is aligned with the second chamber to allow injection of the second fluid.

6. The syringe of claim 5 wherein the outlet is formed at an end of the syringe and a radially enlarged interior portion is formed in the syringe at the end adjacent the outlet, the radially enlarged portion being adapted to receive the disc in a manner such that the disc is disengaged from the tube interior surface and the outlet is aligned with the second chamber after the first fluid is injected.

7. The syringe of claim 6 wherein the radially enlarged portion includes a protrusion adapted to engage the disc in a manner such that the disc is disengaged from the tube interior surface and the outlet is aligned with the second chamber after the first fluid is injected.

8. A syringe comprising a tube with first and second fluids separated from each other in a manner to prevent mixing thereof and an outlet through which the first and second fluid flow when they are injected from the syringe, the outlet being adapted to allow the second fluid to be injected from syringe only after the first fluid has been injected from the syringe.

9. The syringe of claim 8 further comprising a bag disposed in the tube containing the second fluid, and the outlet further comprises a barb formed on an inside of the tube, the barb being adapted to puncture the bag and release the second fluid after the first fluid has been injected from the syringe.

10. The syringe of claim 8 further comprising a plunger sealingly engaged with the tube at an axially end of the tube, the plunger being movable to a first position to inject the first fluid from the syringe and a second position different from the first position to inject the second fluid from the syringe.

11. The syringe of claim 8 further comprising a disc between the first and second fluids, the disc being moveable in an interior of the tube where the disc sealingly engages the tube interior to maintain the first and second fluids separate as the first fluid is injected and disengages from the tube interior thereafter in a manner to align the outlet with the second fluid as the second fluid is injected.

12. The syringe of claim 11 wherein the outlet further comprises a baffle formed on an inside of the tube adjacent the outlet hole, the baffle being adapted to engage the disc after the first fluid has been injected to align the outlet with the second fluid when the second fluid is injected.

13. The syringe of claim 12 wherein the baffle is adapted to hold the disc sufficiently away from the outlet hole when the outlet hole is aligned with the second fluid thereby allowing the second fluid to flow around the disc to the outlet hole when the second fluid is injected.

14. The syringe of claim 12 wherein the baffle has an interior surface for engaging the disc and grooves in the baffle interior surface that form channels in communication with the outlet hole when the disc engages the baffle interior surface, and the second fluid flows around the disc through the channels to the outlet hole when the second fluid is injected.

15. A syringe comprising a tube with an outlet opening at one end of its length, a plunger at an opposite end of its length and a force applying surface disposed in the tube in a manner to form a first and second fluid volumes in the tube when the syringe is filled with a contents, the plunger being movable along a portion of the tube length toward the outlet opening when the contents of the syringe in the first fluid volume is being injected, and the plunger being movable along a remaining portion of the tube length when the contents of the syringe in the second volume is injected.

16. The syringe of claim 15 wherein the second fluid volume comprises a bag disposed in the tube.

17. The syringe of claim 16 wherein the outlet opening comprises a barb adapted to puncture the bag after the contents of the first fluid volume is injected from the syringe.

18. The syringe of claim 16 wherein the force applying surface is a disc adapted to move in an interior of the tube in a manner such that the disc sealingly engages the tube interior as it moves along a portion of the tube length when the contents of the syringe in the first fluid volume is being injected and the disc disengages with the tube interior thereafter thereby allowing the contents of the syringe in the second fluid volume to be injected from the syringe.

19. The syringe of claim 18 wherein the outlet opening further comprises a baffle formed on an inside of the tube adjacent the outlet opening, the baffle being adapted to engage the disc after the contents of the first fluid volume has been injected to align the outlet with the second fluid thereby permitting injection of the contents of the second fluid volume.

20. The syringe of claim 19 wherein the baffle is adapted to hold the disc sufficiently away from the outlet opening when the outlet opening is aligned with the second fluid volume thereby allowing the contents of the second fluid volume to flow around the disc to the outlet opening when the contents of the second fluid volume is injected.

21. The syringe of claim 19 wherein the baffle has an interior surface for engaging the disc and grooves in the baffle interior surface that form channels in communication with the outlet opening when the disc engages the baffle interior surface, and the contents of the second fluid volume flows around the disc through the channels to the outlet opening when the contents of the second fluid is injected.