Front-load angiographic injector system, angiographic syringe and plunger for angiographic syringe

• US 5,947,929 A
• Filed: 08/22/1997
• Issued: 09/07/1999
• Est. Priority Date: 08/22/1997
• Status: Expired due to Term

• Current Assignee: Coeur, Inc. (Illinois Tool Works Inc.)
• Original Assignee: Coeur Laboratories, Inc. (Bison Investments, Inc.)
• Inventors: Trull, Michael Wayne
• Primary Examiner(s): Coggins, Wynn Wood
• Assistant Examiner(s): GRING, NOELLE K
• Application Number:
  US08/916,369
• Time in Patent Office: 746 Days
• Field of Search: 604/154, 604/187, 604/181, 604/218, 604/219, 604/228, 604/152, 604/131, 128/DIG. 1
• US Class Current: 604/152
• CPC Class Codes: A61M 5/007 for contrast media
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod

Abstract

An angiographic syringe and plunger therefor, having utility in a power-driven angiographic syringe injector apparatus comprising an axially extending drive shaft and a frustoconical-shaped driving head attached to the shaft. The plunger is constructed to engage the driving head, with a circumferentially extended array of circumferentially spaced-apart flexible resilient engagement members which compressively bear on the side and rear surfaces of the frustoconical driving head. The flexible resilient engagement members are radially inwardly offset from the edge of the plunger, to avoid contact with inner surfaces of the syringe barrel contamination of the interior volume of the syringe. The syringe is mounted on the injector apparatus by a face plate adapter assembly serving to position the flexible resilient engagement members for coupling to the driving head. Plunger and driving head elements are described which are interactive with a face plate adapter assembly to engage and disengage the plunger and driving head in relation to one another.

Claims

1. A face plate adapter assembly for a front-load syringe injector, including a main body having on a rear face thereof a cylindrical extension with diametrically opposite flange elements for engaging a matably shaped cavity on a front face of an injector apparatus, and lockable in position by rotation of the main body portion so that the diametrically opposite flange elements engage retaining flange elements in the face of the injector apparatus, with a front face of the main body portion having a cylindrical cavity therein and a front slot opening communicating therewith with diametrically opposite retention flange portions transverse to the slot opening, for engagement with a front-load syringe having rear flange members engageable with the slot opening and lockable in position in the face plate adapter assembly by rotation so that the rear flange members of the syringe engage the retention flange portions of the main body, the face plate main body having in the cavity a lifting ring defining an annular volume between the cavity and the lifting ring for engagement with a rear circumferential extremity of a syringe when the syringe is engaged with the face plate adapter assembly, the lifting ring serving to engage with and radially outwardly spread the flexible resilient engagement members of a plunger of the syringe, and wherein the plunger comprises:

a plunger body having a generally convergent distal portion, an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel when the plunger body is operatively positioned within the syringe barrel, and a proximal face including a circumferential surface portion, with an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body and extending rearwardly therefrom;

each of said flexible resilient engagement members having a shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger and terminating in a tail hook portion including a transversely and radially inwardly extending retention surface for matably engaging with a rear circumferential surface of a driving head of an injector when the drive head is operatively coupled with the plunger, each tail hook portion at the retention surface being of increased thickness relative to the shank portion of the flexible resilient engagement member, and of tapering character toward a rearmost extremity thereof, with a convexly shaped inner engagement surface for contacting a frustoconical shaped driving head to compressively engage a frustoconical side surface of the driving head with the transversely radially inwardly extending retention surface matably engaged with a rear circumferential surface of the driving head when the driving head is engaged with the plunger;

the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inwardly spaced from the outer circumferentially continuous edge surface of the plunger, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

2. A front-load syringe injector system including a front-load injector apparatus bearing on a front face thereof a face plate adapter assembly, said face plate adapter assembly including a main body having on a rear face thereof a cylindrical extension with diametrically opposite flange elements for engaging a matably shaped cavity on a front face of an injector apparatus, and lockable in position by rotation of the main body portion so that the diametrically opposite flange elements engage retaining flange elements in the face of the injector apparatus, with a front face of the main body portion having a cylindrical cavity therein and a front slot opening communicating therewith with diametrically opposite retention flange portions transverse to the slot opening, for engagement with a front-load syringe having rear flange members engageable with the slot opening and lockable in position in the face plate adapter assembly by rotation so that the rear flange members of the syringe engage the retention flange portions of the main body, the face plate main body having in the cavity a lifting ring defining an annular volume between the cavity and the lifting ring for engagement with a rear circumferential extremity of a syringe when the syringe is engaged with the face plate adapter assembly, the lifting ring serving to engage with and radially outwardly spread the flexible resilient engagement members of a plunger of the syringe;

an angiographic syringe engaged with the face plate adapter assembly, said syringe comprising a plunger including;

a plunger body having a generally convergent distal portion, an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel when the plunger body is operatively positioned within the syringe barrel, and a proximal face including a circumferential surface portion, with an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body and extending rearwardly therefrom;

each of said flexible resilient engagement members having a shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger and terminating in a tail hook portion including a transversely and radially inwardly extending retention surface for matably engaging with a rear circumferential surface of a driving head of the injector apparatus when the drive head is operatively coupled with the plunger, each tail hook portion at the retention surface being of increased thickness relative to the shank portion of the flexible resilient engagement member, and of tapering character toward a rearmost extremity thereof, with a convexly shaped inner engagement surface for contacting a frustoconical shaped driving head to compressively engage a frustoconical side surface of the driving head with the transversely radially inwardly extending retention surface matably engaged with a rear circumferential surface of the driving head when the driving head is engaged with the plunger;

the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inwardly spaced from the outer circumferentially continuous edge surface of the plunger, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

3. A front-load syringe injector system comprising:

a. a front-load injector apparatus comprising;

(i) a driving mechanism;

(ii) attachment means for disengageably engaging attachment means of a plunger;

b. a face plate adapter assembly operably mounted on the front-load injector apparatus and comprising;

(i) means for attaching the face plate adapter assembly to the front-load injector apparatus;

(ii) a generally cylindrical cavity extending through the face plate adapter assembly, arranged such that, during operation, the driving mechanism can move the driving head through the cavity;

c. a plunger having attached thereto attachment means for engaging the attachment means of the driving mechanism, said plunger attachment means comprising a plunger body having a generally convergent distal portion, an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel when the plunger body is operatively positioned within the syringe barrel, and a proximal face including a circumferential surface portion, with an array of circumferentially spaced-apart flexible resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body extending rearwardly therefrom;

the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inward spaced from the outer circumferentially continuous edge surface of the plunger, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger fowardly or rearwardly through the syringe barrel.

4. A plunger having utility in a power-driven angiographic syringe assembly comprising power driving means including an axially extending reciprocatable drive shaft and a frustoconical shaped driving head attached to said drive shaft, the plunger comprising:

a. a plunger body comprising;

(i) a distal portion;

(ii) an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel;

(iii) a proximal face generally opposite the distal portion comprising a circumferential surface portion;

b. an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body and extending rearwardly therefrom, each of said engagement members comprising;

(i) a flexible shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger;

(ii) a tail hook portion at a rearward terminus of the shank portion comprising;

a) a transversely and radially inwardly extending retention surface, having an attachment point and an inner terminus, for matably engaging with a rear circumferential surface of a drive head of an injector when the drive head is operatively coupled with the plunger,

b) a convexly shaped inner engagement curving rearward generally transverse to and outwardly from the terminus of the retention surface, resulting in a general tapering of the tail hook portion from the retention surface to the rearmost extremity, such that upon contacting a frustoconically shaped driving head, the retention surface can compressively engage a frustoconical side surface of the driving head and the retention surface matably engaged with a rear circumferential surface of the driving head; and

(iii) the array of engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inwardly spaced from the outer circumferentially continuous edge surface of the plunger, such that the flexible resilient engagement members do not contact interior surfaces of a syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

5. An angiographic syringe including a plunger having attached thereto attachment means for engaging the attachment means of a driving mechanism of an injector apparatus, said plunger attachment means comprising a plunger body having a generally convergent distal portion, an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel, a proximal face including a circumferential surface portion with an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body and extending rearwardly therefrom;

the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inward spaced from the outer circumferentially continuous edge surface of the plunger, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

6. An angiographic front-load syringe injector apparatus including an angiographic syringe according to claim 5.

7. A front-load syringe injector system including the angiographic syringe of claim 5.

8. A front-load syringe injector system comprising:

a. a front-load injector apparatus comprising;

(i) a driving mechanism;

(ii) attachment means for disengageably engaging attachment means of a plunger;

b. a face plate adapter assembly operably mounted on the front-load injector apparatus and comprising;

(i) means for attaching the face plate adapter assembly to the front-load injector apparatus;

(ii) a generally cylindrical cavity extending through the face plate adapter assembly, arranged such that, during operation, the driving mechanism can move the driving head through the cavity;

c. a plunger body comprising;

(i) a convergent distal portion;

(ii) an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel;

(iii) a proximal face generally opposite the distal portion comprising a circumferential surface portion with an array of circumferentially spaced-apart flexible resilient engagement members joined to the proximal face of the plunger body and extending rearwardly therefrom;

each of said flexible resilient engagement members having a shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger and terminating in a tail hook portion including a transversely and radially inwardly extending retention surface for matably engaging with a rear circumferential surface of a driving head of an injector when the drive head is operatively coupled with the plunger, each tail hook portion at the retention surface being of increased thickness relative to the shank portion of the flexible resilient engagement member, and of tapering character toward a rear most extremity thereof, with a convexly shaped inner engagement surface for contacting a frustoconical shaped driving head to compressively engage a frustoconical side surface of the driving head with the transversely radially inwardly extending retention surface matably engaged with a rear circumferential surface of the driving head when the driving head is engaged with the plunger;

the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inwardly spaced from the circumferentially continuous edge surface of the plunger, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

9. A face plate adapter assembly for a front-load syringe injector comprising:

a. a face plate main body comprising;

(i) a rear face having a cylindrical extension attached thereto;

(ii) diametrically opposite flange elements attached to the cylindrical extension;

(iii) a front face opposite the rear face having a cylindrical cavity therein;

(iv) diametrically opposite retention flange portions extending from a perimeter of the cylindrical cavity towards the center of the cylindrical cavity and leaving slot openings transverse to the flange portions;

(v) a lifting ring concentrically positioned within the cylindrical cavity of the front face serving to engage with and spread radially outwardly flexible resilient engagement members of a plunger of the syringe;

(vi) an annular volume exterior to the lifting ring for engagement with a rear circumferential extremity of the syringe;

b. a plunger body engageable with the driving head and the main body and comprising;

(i) a distal portion,

(ii) an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel;

(iii) a proximal face generally opposite the convergent distal portion and having a circumferential surface portion;

c. an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face and extending rearwardly therefrom, each of said flexible resilient engagement members comprising;

(i) a flexible shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger;

(ii) a tail hook portion attached at a rearward terminus of the shank portion and comprising a transversely and radially inwardly extending retention surface for matably engaging with a rear circumferential surface of a driving head of an injector when the drive head is operatively coupled with the plunger, the retention surface being of increased thickness relative to the shank portion of the flexible resilient engagement member, and of tapering character toward a rearmost extremity thereof, with a convexly shaped inner engagement surface for contacting a frustoconically shaped driving head to compressively engage a frustoconical side surface of the driving head;

the flexible resilient engagement members being circumferentially arranged such that the flexible resilient engagement members converge towards a center of the outer circumferentially continuous edge surface of the plunger, such that the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

10. A front-load syringe injector system comprising:

a. a front-load injector apparatus comprising a face plate adapter assembly comprising;

(i) a main body;

(ii) a cylindrical extension on a rear face of the main body;

(iii) diametrically opposite flange elements extending outwardly from the cylindrical extension for engaging a matably shaped cavity on a front face of an injector apparatus and lockable in position by rotation of the main body portion so that the diametrically opposite flange elements engage retaining flange elements in the face of the injector apparatus,

(iv) a front face of the main body portion having a cylindrical cavity therein;

(v) diametrically opposite retention flange portions extending radially inwardly from a perimeter of the cylindrical cavity;

(vi) slot openings transverse to the flange portion for engagement with a front-load syringe having rear flange members engageable with the slot openings and lockable in position in the face plate adapter assembly by rotation so that the rear flange members of the syringe engage the retention flange portions of the main body,

(vii) a lifting ring concentrically positioned within the cylindrical cavity of the front face serving to engage with and spread radially outwardly flexible resilient members of a plunger of the syringe;

(viii) an annular volume defined by an outer surface of the lifting ring and an inner surface of the cylindrical cavity of the front face for engagement with a rear circumferential extremity of a syringe when the syringe is engaged with the face plate adapter assembly;

b. an angiographic syringe engaged with the face plate adapter assembly, said syringe comprising a plunger comprising;

(i) a distal portion,

(ii) an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel;

(iii) a proximal face generally opposite the convergent distal portion and having a circumferential surface portion;

(iv) an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face and extending rearwardly therefrom, each of said flexible resilient engagement members comprising;

a) a flexible shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger;

b) a tail hook portion attached at a rearward terminus of the shank portion and comprising a transversely and radially inwardly extending retention surface for matably engaging with a rear circumferential surface of a driving head of an injector when the drive head is operatively coupled with the plunger, the retention surface being of increased thickness relative to the shank portion of the flexible resilient engagement member, and of tapering character toward a rearmost extremity thereof, with a convexly shaped inner engagement surface for contacting a frustoconically shaped driving head to compressively engage a frustoconical side surface of the driving head;

the flexible resilient engagement members being circumferentially arranged such that the flexible resilient engagement members are converge towards a center of the outer circumferentially continuous edge surface of the plunger, such that the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

11. An angiographic syringe including a plunger having utility in a power-driven angiographic syringe assembly comprising power driving means including an axially extending reciprocatable drive shaft and a frustoconical shaped driving head attached to said drive shaft, the plunger comprising:

a. a plunger body comprising;

(i) a distal portion;

(ii) an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel;

(iii) a proximal face generally opposite the distal portion comprising a circumferential surface portion;

b. an array of circumferentially spaced-apart flexible, resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body and extending rearwardly therefrom, each of said engagement members comprising;

(i) a flexible shank portion rearwardly extending from the circumferential surface portion of the proximal face of the plunger;

(ii) a tail hook portion at a rearward terminus of the shank portion comprising;

a) a transversely and radially inwardly extending retention surface, having an attachment point and an inner terminus, for matably engaging with a rear circumferential surface of a drive head of an injector when the drive head is operatively coupled with the plunger,

b) a convexly shaped inner engagement curving rearward generally transverse to and outwardly from the terminus of the retention surface, resulting in a general tapering of the tail hook portion from the retention surface to the rearmost extremity, such that upon contacting a frustoconically shaped driving head, the retention surface can compressively engage a frustoconical side surface of the driving head and the retention surface matably engaged with a rear circumferential surface of the driving head; and

the array of engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inwardly spaced from the outer circumferentially continuous edge surface of the plunger, such that the flexible resilient engagement members do not contact interior surfaces of a syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

12. A front-load syringe injector system including the angiographic syringe of claim 11.

13. An angiographic syringe including a plunger having attached thereto attachment means comprising a plunger body having a generally convergent distal portion, an outer circumferentially continuous edge surface for engaging an interior surface of a syringe barrel when the plunger body is operatively positioned within the syringe barrel, and a proximal face including a circumferential surface portion, with an array of circumferentially spaced-apart flexible resilient engagement members joined to the circumferential surface portion of the proximal face of the plunger body extending rearwardly therefrom, the array of circumferentially spaced-apart flexible resilient engagement members being circumferentially arranged on the circumferential surface portion of the proximal face of the plunger so that the flexible resilient engagement members are radially inward spaced from the outer circumferentially continuous edge surface of the plunder, whereby the flexible resilient engagement members do not contact interior surfaces of the syringe barrel during translation of the plunger forwardly or rearwardly through the syringe barrel.

14. A front-load syringe injector system including the angiographic syringe of claim 13.

15. A plunger for a front-load syringe injector system comprising:

a. a circumferential surface for engaging the inner surface of a syringe barrel; and

b. a proximal face having attached thereto two or more flexible shank members extending rearwardly therefrom, said flexible shank members comprising a tail hook portion at a rearward terminus of the shank portion, said tailhook portion comprising a retention surface, and said flexible shank members being configured so that they do not touch the syringe barrel upon entry thereinto.

16. The plunger of claim 15 further comprising a conical front face.

17. The plunger of claim 15 wherein the flexible shank members are radially positioned around a circumference of the proximal face of the plunger.

18. The plunger of claim 15 comprising 3 or more flexible shank members radially positioned around a circumference of the proximal face of the plunger.

19. The plunger of claim 15 comprising 4 or more flexible shank members radially positioned around a circumference of the proximal face of the plunger.

20. The plunger of claim 15 wherein the hook portions of the tail hook members face inwardly.

21. The plunger of claim 15 wherein the tail hook portions further comprise an engagement surface curving rearward generally transverse to and away from a terminus of the retention surface, to provide in a general tapering of the tail hook portion from the retention surface to the rearmost extremity.

22. The plunger of claim 21 wherein the engagement surface is convexly shaped.

23. The plunger of claim 21 configured such that upon contacting a frustoconically shaped driving head, the retention surface compressively engages a frustoconical side surface of the driving head and the retention surface matably engages with a rear circumferential surface of the driving head.

24. The plunger of claim 15 wherein the plunger is engageable while the plunger is positioned within the syringe barrel such that the hook members no not extend outside the syringe barrel.

25. An angiographic syringe comprising:

a. a syringe barrel, and

b. a plunger comprising;

(i) a circumferential surface for engaging the inner surface of a syringe barrel; and

(ii) a proximal face having attached thereto two or more flexible shank members extending rearwardly therefrom, said flexible shank members comprising a tail hook portion at a rearward terminus of the shank portion, said tailhook portion comprising a retention surface, and said flexible shank members being configured such that such members do not touch the syringe barrel upon entry thereinto.

26. The angiographic syringe of claim 25 wherein the plunger further comprises a conical front face.

27. The angiographic syringe of claim 25 wherein the flexible shank members are radially positioned around the circumference of the proximal face of the plunger.

28. The angiographic syringe of claim 25 wherein the plunger further comprises 3 or more flexible shank members radially positioned around the circumference of the proximal face of the plunger.

29. The angiographic syringe of claim 25 wherein the plunger further comprises 4 or more flexible shank members radially positioned around the circumference of the proximal face of the plunger.

30. The angiographic syringe of claim 25 wherein the hook portions of the plunger face inwardly.

31. The angiographic syringe of claim 25 wherein the tail hook portions of the plunger further comprise an engagement surface curving rearward generally transverse to and away from a terminus of the retention surface, to provide a general tapering of the tail hook portion from the retention surface to the rearmost extremity.

32. The angiographic syringe of claim 31 wherein the engagement surface is convexly shaped.

33. The angiographic syringe of claim 31 wherein the plunger is configured such that, upon contacting a frustoconically shaped driving head, the retention surface compressively engages a frustoconical side surface of the driving head and the retention surface matably engages with a rear circumferential surface of the driving head.

34. The angiographic syringe of claim 25 wherein the plunger is configured such that the plunger is engageable while the plunger is positioned within the syringe barrel such that the hook members no not extend outside the syringe barrel.

35. An angiographic injector system comprising:

a. a driving mechanism including a driving head;

b. a face plate adapter assembly operably mounted on the front-load injector apparatus and comprising;

(i) means for attaching the face plate adapter assembly to the front-load injector apparatus;

(ii) a cavity extending through the face plate adapter assembly, arranged such that, during operation, the driving mechanism can move the driving head through the cavity; and

(iii) means for attaching a syringe barrel to the face plate adapter assembly;

c. a plunger comprising;

(i) a circumferential surface for engaging the inner surface of a syringe barrel; and

(ii) a proximal face having attached thereto two or more flexible shank members extending rearwardly therefrom, said flexible shank members comprising a tail hook portion at a rearward terminus of the shank portion, said tailhook portion comprising a retention surface, and said flexible shank members being configured such that such members do not touch the syringe barrel upon entry thereinto.

36. The angiographic injector system of claim 35 wherein the plunger further comprises a conical front face.

37. The angiographic injector system of claim 35 wherein the flexible shank members are radially positioned around the circumference of the proximal face of the plunger.

38. The angiographic injector system of claim 35 wherein the plunger further comprises 3 or more flexible shank members radially positioned around the circumference of the proximal face of the plunger.

39. The angiographic injector system of claim 35 wherein the plunger further comprises 4 or more flexible shank members radially positioned around the circumference of the proximal face of the plunger.

40. The angiographic injector system of claim 35 wherein the hook portions of the plunger face inwardly.

41. The angiographic injector system of claim 35 wherein the tail hook portions of the plunger further comprise an engagement surface curving rearward generally transverse to and outwardly from a terminus of the retention surface, to provide 0a general tapering of the tail hook portion from the retention surface to the rearmost extremity.

42. The angiographic injector system of claim 41 wherein the engagement surface is convexly shaped.

43. The angiographic injector system of claim 41 wherein the plunger is configured such that upon contacting a frustoconically shaped driving head, the retention surface compressively engages a frustoconical side surface of the driving head and the retention surface matably engages with a rear circumferential surface of the driving head.

44. The angiographic injector system of claim 41 wherein the plunger is configured such that the plunger is engageable while the plunger is positioned within the syringe barrel such that the hook members no not extend outside the syringe barrel.

45. The angiographic injector system of claim 41 wherein the face plate further comprises a lifting ring positioned such that as the plunger is fully retracted, the lifting ring engages the convexly shaped inner engagement surface and forces the tailhook portions to disengage the driving head.

46. The angiographic injector system of claim 45 wherein the lifting ring further comprises a conical side face for engagement with the convexly shaped inner engagement surface of the tail hook portions.

47. The angiographic injector system of claim 41 wherein the driving head comprises:

a. means for forcing the tail hook portions outward upon initial engagement with the inner engagement surface; and

b. means to permit the tail hook portions to flex inwardly as the driving head is moved from the position of initial engagement to a position of locking engagement with the driving head.

48. The angiographic injector system of claim 41 wherein:

a. the driving head comprises;

(i) means for forcing the tail hook portions outward upon initial engagement with the inner engagement surface; and

(ii) means to permit the tail hook portions to flex inwardly as the driving head is moved from the position of initial engagement to a position of locking engagement with the driving head; and

b. the face plate further comprises a lifting ring positioned such that as the plunger is fully retracted, the lifting ring engages the engagement surface and thereby forcing the tailhook portions to disengage the driving head.