Plunger for power-driven angiographic syringe, and syringe and power injector system utilizing same

A plunger having a generally converging distal portion, and a proximal face on which is mounted a coupling structure. The coupling structure is transversely engageable by, and transversely disengageable from, a driving mechanism of a power-driven angiographic syringe, and once engaged, cannot be disengaged by rotation of the driving mechanism relative to the plunger in the absence of transverse translational movement of the driving mechanism and plunger relative to one another. The coupling structure may include a pair of laterally spaced-apart retention members, each comprising a leg rearwardly extending from the proximal face of the plunger and joined at a rearward part thereof to a laterally extending bridge segment, to the inner extremity of which is joined a pair of oppositely transversely extending flexible, resilient flange elements. The flange elements of the respective retention members thus define a transverse channel therebetween, with marginal portions thereof having reduced width dimensions relative to a medial portion thereof. Such plunger has utility in angiographic syringes of a type employed with power injector means which comprise a driving mechanism with a head engageable with the coupling structure of the plunger.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention generally relates to power-driven angiographic syringes, and 
specifically to a plunger for such a syringe, and to the syringe and power 
injector system comprising same. 
2. Description of the Related Art 
In the field of angiography, a contrast medium of suitable indicating 
character (radiopacity) is introduced under pressure into coronary 
arteries, and the arterial network then is monitored by fluoroscopic or 
other visualizing means. As a result, arterial plaque deposits and/or 
other arterial occlusions are readily visually determined as to their size 
and location, so that suitable treatment methods, such as removal of the 
occluding material by lasing or mechanical excision, or displacement 
techniques such as balloon angioplasty, may be carried out. 
To effect the introduction of the contrast medium into the arterial network 
for angiographic study, it has been common practice to utilize injector 
syringes in combination with arterial catheters. The syringe may be 
machine-mounted in a so-called "power injector" apparatus, with the distal 
end of the syringe being connected to the catheter which is introduced 
into the arterial system to be studied. 
There is disclosed in U.S. Pat. No. 4,677,980 issued July 7, 1987 to D. M. 
Reilly, et al, an angiographic power injector featuring a rotating turret 
for housing multiple angiography syringes in readiness for injection. In 
use, the turret is selectively rotated to align an angiographic syringe 
with a driving mechanism of the power injector. Specifically, as is shown 
in FIGS. 9 and 10 of this patent, the plunger of the angiographic syringe 
may be configured wit rearwardly extending hook members which are engaged 
by the head and stem portion (typically termed a "ram" in the field) of 
the driving mechanism. 
In the plunger configuration disclosed in this patent, the hook elements on 
the proximal face of the plunger are diametrically opposed to one another, 
to form a slot therebetween through which the ram head is inserted and 
subsequently rotated, the head being of transversely extending character, 
so that it thereby engages the respective hook members. In this manner, 
the head and stem of the driving mechanism and the hook members are 
described to constitute a quick release driving connection, with the 
driving mechanism head fitting into the aperture formed by the hook 
members, and with the stem extending out from the aperture through the 
access slot between the hook members. 
The Reilly et al patent, at column 6, lines 24-52 thereof, describes the 
subsequent operation of the coupled syringe. First, the driving mechanism 
is forwardly translated to drive the plunger through the syringe to expel 
air therefrom. Next, the syringe is connected to a source of contrast 
media and the driving mechanism is retracted to pull the plunger back 
through the syringe, to draw contrast media thereinto. Finally, the 
driving mechanism is advanced to drive the plunger distally in the syringe 
and effect injection of the contrast media through a catheter attached to 
the syringe. The patent states that after the injection has been carried 
out, the driving mechanism may be disengaged from the plunger, without 
reversing its movement, by the simple expedient of rotating the driving 
mechanism 90.degree., so that the driving mechanism head extends from the 
aperture on either side (see FIG. 10 of the patent). Subsequent retraction 
of the driving mechanism results in the head and stem of the driving 
mechanism being withdrawn from the aperture and slot thereby disengaging 
he driving mechanism from the plunger. 
As a result of the foregoing configuration of the driving mechanism, and 
the hook members on the plunger, the risks incident to retracting the 
plunger through the syringe during the angioplasty procedure are said to 
be eliminated, and the mating hook members and driving mechanism head are 
said to cooperate so that the plunger can be placed in either a driven 
retractable state, or an undriven non-retractable state, at any time 
during the injection operation and at any position of the plunger, without 
substantial force being applied therebetween. 
While the foregoing configuration of the hook members on the plunger 
facilitates the engagement and disengagement of the driving mechanism, 
without change in the position of the plunger, it also is true that the 
hook members themselves provide only a very small contact area for mating 
with the head of the driving mechanism, when the driving mechanism is in 
driving or retraction engagement with the hook members. 
There is thus the danger that the head of the driving mechanism may 
disengage from contact with the hook members during operation of the 
syringe, so that subsequent rotation of the driving mechanism to effect 
disengagement actually effects re-engagment of the driving mechanism with 
the hook members, in turn causing retraction of the plunger, an occurrence 
which specifically is desired to be avoided. 
The Reilly et al patent discloses other plunger and driving mechanism 
constructions, e.g., as shown in FIGS. 11-21 of the patent, but all such 
alternative constructions are relatively more complex in construction and 
operation. 
Prior copending U.S. patent application No. 07/299,974 filed Jan. 19, 1989 
in the names of L. L. Densmore and T. A. Lindner, discloses an 
angiographic syringe plunger having a generally converging distal portion, 
and a rear face on which is provided a coupling structure which is 
transversely engageable by, and transversely disengageable from, a driving 
mechanism of a power-driven angiographic syringe. Once engaged by the 
driving mechanism, the plunger cannot be disengaged solely by rotation of 
the driving mechanism relative to the plunger in the absence of 
translational movement of the driving mechanism and plunger relative to 
one another. The coupling structure disclosed in this application includes 
a wall extending rearwardly from the proximal face of the plunger body and 
partially circumferentially thereon. The wall terminates at a proximal 
extremity, and a radially inwardly extending flange is joined at a outer 
peripheral portion thereof to the proximal extremity of the wall. In such 
manner, the radially inwardly extending flange and the wall form with the 
proximal face of the plunger a cavity transversely open to insertion of a 
ram head thereinto. 
For example, the coupling structure described in this prior copending 
application may be generally C-shaped, with a continuously curved portion 
having an arc length not exceeding about 180.degree., and optionally 
provided with tangentially extending end segments respectively joined to 
the extremities of the continuously curved portion. 
A disadvantage of the plunger construction described in copending U.S. 
patent application No. 07/299,974 is that the coupling structure thereof 
has a "directional" character, in that the plunger proximal face must be 
rotationally aligned with the head of the driving mechanism, to permit 
lateral engagement of the driving mechanism head with the cavity which is 
defined by the coupling means with the proximal face of the plunger. A 
corresponding orientation of the plunger and coupling mechanism likewise 
is required for lateral disengagement of the driving mechanism head from 
this cavity. As a result, this prior application discloses the use of 
registration marks on the plunger, for alignment thereof with a 
corresponding alignment mark on the carrousel of the power injector system 
(see, for example, FIG. 7 of this prior copending application, the 
disclosure of which hereby is incorporated herein by reference). 
Even with such a registration system, however, the turret or carrousel 
arrangement employed on angiograpic syringe power injector systems 
necessitates that the ram access the plunger from two opposing directions. 
In other words, as the ram head is disengaged from the plunger of a first 
angiographic syringe in the carrousel, the carrousel is rotated to access 
a second angiographic syringe for engagement by the ram head. Since the 
ram head is engaging the respective first and second angiographic syringes 
from opposite directions, the plungers must be correspondingly "faced" in 
the proper engagement direction. 
The directional difficulties associated with the provision of a 
multiplicity of angiographic syringes on a carrousel of a power injector 
system may thus be overcome by the above-described provision of alignment 
marks on the plunger and carrousel, however it may be difficult in 
practice to achieve the precise registration of alignment marks required 
for the effective use of the power injection system, particularly in use 
environments in which time is of critical importance. 
Accordingly, it is an object f the present invention to provide a plugger 
which is readily engageable with the driving mechanism of a power injector 
system from both of two opposing directions. 
It is another object of the present invention to provide an angiography 
syringe comprising such a plunger. 
It is a further object of the present invention to provide an angiography 
power injector system comprising an angiography syringe including such a 
plunger. 
Other objects and advantages of the present invention will be more fully 
apparent from the ensuing disclosure and appended claims. 
SUMMARY OF THE INVENTION 
In one aspect, the present invention relates to a plunger having utility in 
a power-driven angiographic syringe assembly comprising power driving 
means including an axially extending driving shaft and a transversely 
extending driving head attached to the shaft. 
The plunger includes a plunger body having a generally convergent distal 
portion and a proximal face. 
Laterally spaced-apart retention members are disposed on the proximal face 
e.g., in diametrally opposite relationship to one another on the proximal 
face, for retaining the power driving means in position once engaged with 
the plunger. Each retention member comprises a leg portion extending 
generally rearwardly (proximal) from the proximal face and joined at a 
rearward part thereof to a bridge segment laterally inwardly extending 
therefrom toward the other retention member, to an inner extremity, which 
is in spaced relationship to the corresponding inner extremity of the 
bridge segment of the other retention member. 
The inner extremities of the bridge segments thereby define a spacing 
accommodating transverse passage of the drive shaft therethrough. The leg 
portions and bridge segments of the retention members corporately define 
with the proximal face of the plunger a lateral slot accommodating 
transverse passage of the driving head therethrough. 
Transversely outwardly extending flexible, resilient flange elements are 
joined to the inner extremity of each of the aforementioned bridge 
segments and form laterally spaced-apart, transversely aligned pairs of 
flange elements on either side of the bridge segments, defining a 
transverse channel therebetween. The flange elements are shaped to define 
marginal portions of the transverse channel having a reduced channel width 
relative to a medial portion thereof. The marginal channel portions allow 
transverse passage of the drive shaft therethrough by deformation of the 
flange elements bounding the marginal channel portions so that the drive 
shaft thereafter is retentively held in the medial portion of the 
transverse channel to accommodate free rotation of the driving mechanism 
relative to the plunger without disengagement of the driving mechanism 
therefrom. 
The invention relates in another aspect to an angiographic syringe 
comprising a plunger of the above-described construction. 
In a still further aspect, the invention relates to a power injector system 
comprising an angiographic syringe including a plunger of the 
above-described construction. 
Other aspects and features of the invention will be more fully apparent 
from the ensuing disclosure and appended claims.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENTS THEREOF 
Referring now to the drawings, there is shown in FIG. 1 a perspective view 
of a plunger 10 in accordance with one embodiment of the present 
invention. The plunger as illustrated comprises a plunger body 12 and a 
frontal sheath 14. 
The plunger body 12 has a conical distal end portion 16 extending 
proximally to a distal cylindrical portion 18, rearwardly of which is 
provided a cylindrical proximal portion 20. The respective distal and 
proximal cylindrical portions 18 and 20 of the plunger body are in axial 
spaced relationship to one another. Between the respective cylindrical 
portions 18 and 20 is a groove 22, having an interior surface defined by 
the intermediate cylindrical portion 24 of the plunger body. The central 
axis of the plunger assembly as shown in FIG. 1 is indicated by line L--L. 
The proximal cylindrical portion 20 of the plunger body 12 features a 
proximal face 26 which preferably is generally planar as shown. 
Reposed on the proximal face 26 is a coupling structure comprising power 
driving means (ram) retention members 30 and 32, which as shown are 
symmetrically disposed on the proximal surface 26, diametrally opposite 
and laterally spaced apart from one another, in symmetrical relationship 
to the central axis L--L of the plunger. 
With regard to retention member 30, the same comprises a leg portion 34 
extending generally rearwardly from the proximal face 26 and joined at a 
rearward part thereof to a bridge segment 36 which laterally inwardly 
extends from the rearward part of the leg portion 34 toward the other 
retention member 32, which is similarly constructed with leg portion 38 
and bridge segment 40. The inner extremities of the respective bridge 
segments 36 and 40 of the laterally opposed retention members are thus in 
spaced relationship to one another to accommodate transverse passage of 
the drive shaft of a driving mechanism therethrough. 
For ease of descriptive reference in the ensuing discussion, the term 
"transverse" will generally refer to the direction of engagement of the 
power driving means (ram) with the plunger, and the direction of 
disengagement therefrom. In FIG. 1 this direction is generally indicated 
by the transverse line A--A. The transverse dimension thus is generally 
perpendicular to the central axis L--L of the plunger, as illustrated. The 
term "lateral" as used herein refers to a direction which is generally 
perpendicular to the transverse direction as well as to the axis L--L, and 
is indicated in FIG. 1 by the lateral line B--B. 
The leg portion 34 and bridge segment 36 of retention member 30 defines 
with the proximal face 26 of the plunger a slot 42. Correspondingly, the 
leg portion 38 and bridge segment 40 of retention member 32 defines with 
the proximal face 26 a slot 44. There is thus define an overall laterally 
extending slot comprising slot segments 42 and 44 which accommodates 
transverse passage of the driving head of the driving means therethrough. 
At the inner lateral extremity of bridge segment 36 of retention member 30 
is joined transversely outwardly extending flange elements 46 and 48. 
Retention member 32 is similarly configured, with transversely outwardly 
extending flange elements 50 and 52 joined to the inner lateral extremity 
of bridge segment 40. The respective flange elements 46, 48, 50 and 52 are 
formed of a flexible, resilient material accommodating lateral deformation 
of these flange elements, as hereinafter more fully described. 
The plunger construction shown in FIG. 1 provides transversely aligned 
pairs of the laterally spaced-apart flange elements, viz., a first flange 
element pair comprising flange elements 46 and 50, and a second flange 
element pair comprising flange elements 48 and 52, on the respective sides 
of the bridge segments. In such manner, the paired flange elements bound 
and define a transverse channel 60 therebetween. 
The plunger body 12 may be formed, if desired, with a central cavity 
therein (not shown), as described in the aforementioned prior copending 
U.S. patent application No. 07/299,974, to minimize weight and material 
requirements for the plunger, as well as to facilitate molding, by 
providing faster mold cycling times, when the plunger body is formed of a 
molded material. 
The distal sheath 14 of the plunger is adapted to fit matingly over the 
distal conical portion 16, and the respective distal and intermediate 
cylindrical portion 18 and 24, of the plunger body. The distal sheath 
preferably is formed of a resilient material, of sufficient intrinsic 
lubricity or amenability to lubrication, to yield it slidingly engageable 
with the inner wall surface of a syringe in which the plunger is deployed. 
The distal sheath 14 comprises distal conical portion 72 and a proximal 
portion 74 whose outer surface describes axially spaced-apart ridges 76 
and 78 bounding a groove 80 therebetween. 
The sheath wall is of generally uniform thickness along the conical distal 
portion 72. At its rearward extremity the sheath wall forms a radially 
inwardly extending flange 82 which mates cooperatively with the groove 22 
of the plunger body, when the sheath and body of the plunger are 
cooperatively mated with one another. 
In general, the plunger body 12 may be formed of any suitable material of 
construction which is advantageously employed in the use environments of 
the plunger and syringe with which the plunger may be associated. The 
plunger body may for example be formed of a generally stiff, resilient 
material, such as a hard elastomer, or alternatively, it may be formed of 
any other suitable natural or synthetic, polymeric or non-polymeric, 
materials. In practice, plastics generally are preferred materials of 
construction. A polymeric material which may be employed to good advantage 
in such plunger body is polyphenylene oxide, such as the polyphenylene 
oxide material commercially available from General Electric Company, 
Pittsfield, Mass., under the trademark Valox.RTM.. The plunger sheath 14 
likewise may be formed of any suitable material which is advantageously 
employed in the use environments of the plunger and syringes with which 
same is associated. Preferred materials of construction include rubber 
materials, with natural rubber typically being the most preferred. The 
sheath is suitably flexible, resilient, and elastomeric in character, to 
accommodate mating with the plunger body in a manner ensuring that the 
sheath is retained in position on the plunger body during the use of the 
plunger. 
The retention members 30 and 32 may be formed of any suitable materials of 
construction, with the proviso that the flange elements 46, 48, 50, and 52 
must be flexible and resilient in character, to accommodate deformation 
thereof during the engagement and disengagement of the drive means during 
the use of the plunger in a power-driven angiographic syringe system. 
Accordingly, the retention members 30 and 32 may be formed of the same 
material of construction as the plunger body 12, if such material provides 
the requisite structural integrity in the plunger body and leg portions 
and bridge segments of the coupling structure, while concomitantly 
providing sufficient flexibility and resilience in the flange elements 46, 
48, 50, and 52. 
In this respect, the retention members 30 and 32 may be formed integrally 
with the plunger body 12, such as by injection molding, machining, or 
other suitable forming method(s). Alternatively, the retention members 30 
and 32 may be formed separately from the plunger body, and affixed thereto 
at the lower extremities of the respective leg portions 34 and 38 by any 
suitable means or methods efficacious for such securement, e.g., adhesive 
bonding, ultrasonic welding, fusion bonding, mechanical fastening, etc. 
As a further alternative, the flange elements may be formed separately from 
the leg portions and bridge segments of the respective retention members, 
or any two of such elements may be formed separately from the third, and 
correspondingly joined in any suitable manner. For example, the leg 
portions and bridge segments of the respective retention members may be 
integrally molded from a suitable plastic material with the plunger body 
and subsequent to such formation, flange elements 46, 48, 50, and 52 may 
be suitably attached to the inner lateral extremities of the corresponding 
bridge segments. 
A perspective view of a plunger, as assembled from the sheath and body 
components of FIG. 1, is shown in FIG. 2, wherein all parts and elements 
are numbered correspondingly with respect to the same or corresponding 
features in FIG. 1. 
FIG. 3 is a perspective view of a portion of a driving mechanism including 
an axially extending shaft 88, joined at its lower extremity (in the 
position shown) to a driving head 90. The drive shaft 88 and driving head 
90 corporately are referred to herein as the "ram" of the power injector 
system. 
FIG. 4 is a perspective view of a proximal surface portion of a plunger 
according to one embodiment of the present invention, with the coupling 
means on proximal face 26 engaged with the ram comprising shaft 88 and 
driving head 90. In the FIG. 4 drawing, all parts and features are 
numbered correspondingly with respect to FIGS. 1-3 herein. 
In the FIG. 4 engaged plunger assembly, the shaft 88 of the ram is engaged 
in a central (medical) portion of the transverse channel 60 which is 
bounded by the respective flange elements 46, 48, 50, and 52. These flange 
elements are joined to the corresponding bridge respective retention 
members 30 and 32. 
As previously described, retention member 30 comprises a leg portion 34 
joined to a laterally extending bridge segment 36, to the innermost 
lateral extremity of which are joined transversely outwardly extending 
flange elements 46 and 48, in the previously described manner. 
Correspondingly, retention member 32 comprises leg portion 38, which is 
joined at rearward part thereof to laterally extending bridge segment 40. 
Flange elements 50 and 52 are joined at their respective transversely 
inner extremities to the lateral inner extremity of the bridge segment 40. 
FIG. 5 is a corresponding view of the FIG. 4 engaged plunger assembly, 
wherein all parts and features are correspondingly numbered, but wherein 
the shaft 88 has been rotated by 90.degree. relative to the position shown 
in FIG. 4. As shown, the retention members 30 and 32 are dimensionally 
sized and shaped to accommodate free rotation of the driving head 90 
incident to rotation of driving shaft 88, with the provision of a 
laterally extending slot comprising slot segments 42 and 44 between the 
proximal face 26 of he plunger and the respective leg portions and bridge 
segments of the retention members. 
FIG. 6 is a top plan view of the proximal surface 26 of the plunger 
according to one embodiment of the present invention featuring a coupling 
structure mounted on the proximal face including retention members 30 and 
32. The proximal face of the plunger and the coupling structure thereon 
are shown in associative relationship with a ram comprising driving shaft 
88, to which is joined a driving head 90 in the manner shown and described 
with reference to FIG. 3 herein. The ram and plunger shown in FIG. 6 are 
numbered correspondingly with respect to FIGS. 1-5 herein. 
As shown, the flange elements 46 and 48 are joined at their inner 
transverse extremities to the bridge segment 36 of retaining member 30. In 
like fashion, flange elements 50 and 52 are joined at their inner 
transverse extremities to bridge segment 40 of retaining member 32. The 
respective bridge segments 36 add 40 may, as shown, be formed with 
laterally extending cavities 94 and 96, respectively, to enhance the 
flexible and resilient character of the flange elements attached thereto. 
Thus, the respective retention members 30 and 32 may be configured with a 
flattened "wishbone" shape as shown in the plan view illustrated. 
In the FIG. 6 drawing, the respective flange elements 46, 48, 50, and 52 
corporately bound and define a transversely extending channel 60 (the 
transverse center line A--A of such channel being shown for ease of 
reference). 
The transverse channel 60 comprises a medial portion 100, and marginal 
portions 102 and 104. In the marginal portions of the transverse channel, 
the overall flattened W-shape of the respective pairs of flange elements 
transversely bounding the channel 60 (viz., flange elements 46 and 48 as a 
first pair, and flange elements 50 and 52 as a second pair) provides a 
channel configuration wherein the marginal channel portions 102 and 104 
are of reduced channel width relative to the medial portion 100 of the 
channel. 
Thus, the marginal portion 104 of the passage 60 defines a channel width at 
the point of closest proximity of the respective facing flange elements 48 
and 52 which is denoted as dimension W in the FIG. 6 drawing. 
At the opposite end of the transverse channel, at the marginal portion 102 
thereof, the normal width dimension W of such portion of the channel is 
indicated, with the respective facing flange elements 46 and 50 bounding 
such marginal portion of the channel being laterally displaced in the 
direction of arrows C and D, respectively, to indicate the deformation of 
these flange elements which occurs when the driving means comprising 
driving shaft 88 and driving head 90 is translated in the transverse 
direction indicated by arrow E for engagement with the retention members. 
Accordingly, the driving mechanism is engaged with the plunger 10 by 
translating the driving means comprising shaft 88 and head 90 in the 
direction of arrow E along transverse center line A--A, to cause same to 
pass successively through the marginal portion 102 of the transverse 
channel 60 to the medial portion 100 thereof, to finally repose in the 
position indicated in dotted line outline, on which the diameter of the 
driving shaft 88 is indicate as dimension D.sub.1. 
After passage of shaft 88 through marginal portion 102 of the transverse 
channel 60 to the medial portion 100 thereof the facing flange elements 46 
and 50 bounding marginal portion 102 of the channel will of course return 
to their normal configuration defining a spacing width W, by lateral 
return movement of these respective flange elements in directions opposite 
to those indicated by arrows C and D in the drawings. 
Once the driving mechanism comprising shaft 88 and head 90 is reposed in 
the medial portion 100 of the transverse channel 60, it will be apparent 
that the driving mechanism thereafter is non-disengageable from the 
plunger by simple rotation of the driving head relative to the plunger. 
Accordingly, it is possible to disengage the driving mechanism from the 
plunger, once engaged therewith, only by transverse translation of the 
driving mechanism relative to the plunger, i.e., translation of the 
driving mechanism in a direction along transverse center line A--A. It 
will also be appreciated that the driving mechanism may be thus disengaged 
from the plunger in both transversely opposite directions. In other words, 
the driving mechanism, once reposed in the medial portion 10 of the 
transverse channel, can be disengaged from the plunger by either 
transverse translation through the marginal channel portion 102, or by 
transverse translation of the driving mechanism through marginal channel 
104. 
Accordingly, the bi-directional character of the driving mechanism 
engagement and retention means in the plunger of the present invention 
overcomes the difficulties associated with the directional character of 
the plunger disclosed in prior copending U.S. patent application No. 
07/299,974 filed Jan. 19, 1989. 
FIG. 7 is a side elevation view, in partial section, showing an angiograhic 
syringe comprising the plunger of the present invention, add an associated 
part of the driving mechanism of an angiography power injector system, in 
engagement with the plunger. 
The angiographic syringe 170 comprises a generally cylindrical barrel 172, 
which terminates at its proximal end in a circumferentially continuous, 
radially extending flange 174. 
The plunger 110 is reposed in the interior volume 175 of the angiographic 
syringe 170, with the ridges 146 and 148 of the plunger sheath being in 
contact with the inner wall surface 180 of the angiographic syringe. 
The plunger comprises a coupling structure 128 as previously described in 
FIGS. 1-6 hereof, with the retention members 130 and 132 corporate 
defining with the rear face 126 of the plunger a cavity 182. The cavity 
182 is constructed and arranged for transversely receiving the head 184 of 
the driving mechanism 186. Flange elements 190 and 192, together with 
corresponding flange elements on the opposite side of the plunger from 
that shown, corporately define a transversely extending channel into which 
the head 184 and shaft 188 of the driving mechanism are transversely 
inserted for engagement with the plunger, and from which the head and 
shift of the driving mechanism are transversely withdrawn for 
disengagement from the plunger, as previously described. The driving head 
184 thus is mounted on the axially extending drive shaft 188, and the 
driving mechanism comprises means (not shown) for axially extending or 
retracting the shaft 188 and head 184 as desired. 
FIG. 8 is a side elevation view, in section, of an angiographic syringe 
according to one embodiment of the present invention, comprising a plunger 
of the type shown in FIGS. 1-7 hereof. 
As illustratively shown in FIG. 8, the angiographic syringe 270 comprises a 
generally cylindrical barrel 272 enclosing an interior volume 275 in which 
the plunger 210 is slidably mounted, in engagement, at ridges 246 and 248, 
with the inner wall surface 280 of the syringe barrel. The syringe barrel 
terminates at a proximal end in radially outwardly extending flange 274. 
At its distal end, the syringe barrel 272 is joined via a frustoconical 
section 290 to distal tapered section 292, which in turn is joined at a 
distal extremity thereof to the tubular discharge section 294. The tapered 
section 292 of the syringe optionally features, at a proximal portion 
thereof, a plurality of vanes 276, which may be employed for positive 
locking of the syringe in the mounting structure of a power injector 
system. The tapered section 292 features o a distal portion of its 
exterior surface a threading 298, by means of which the angiographic 
syringe may be coupled, via a suitable complimentarily threaded connecting 
fitting, to an angiography catheter (not shown). 
FIG. 9 is a perspective view of an angiography injection system 300 
including power injector 302. The power injector comprises a carrousel 304 
mounted for rotation, e.g., in the direction indicated by arrow S in FIG. 
9, and contains openings bounded by collars 306 through which syringes 
370a and 370b are inserted. As shown in FIG. 9, the lower syringe 370b has 
been placed, by selective adjustment of the carrousel, in engagement 
position with the driving mechanism of the power injector 302, so that the 
plunger 310b of syringe 370b is in engagement with the head and shaft of 
the driving mechanism. Concurrently, the angiographic syringe 370a, 
comprising plunger 310a, is mounted in position on the upper segment of 
the carrousel, for subsequent translation into alignment with the power 
injector driving mechanism, and concurrent disengagement of the plunger 
310b of syringe 370b therefrom. 
As an illustrative example of an embodiment of the plunger of the 
invention, such as may be usefully employed with a 150 milliliter 
angiographic syringe, the plunger, of a type as shown in the respective 
drawings of FIGS. 1-9 hereof, may have a body formed of Valox.RTM. 
polyphenylene oxide (General Electric Company, Pittsfield, Mass.) and a 
sheath of natural rubber. The conical distal portion 16 of the body (see 
FIG. 1) comprises surfaces which define with the central axis of L--L of 
he body an included angle of 45.degree.. The diameter of the proximal 
cylindrical portion 20 of the plunger is 1.59 inch, the diameter of the 
distal cylindrical portion 18 of the plunger is 1.405 inch, and the 
diameter of the intermediate cylindrical portion 24 of the plunger is 
1.165 inch. The distal cylindrical portion 20 of the plunger in this 
illustrative embodiment has an axial thickness of 0.125 inch, the 
intermediate cylindrical portion 24 of the plunger has an axial thickness 
of 0.18 inch, and the distal cylindrical portion 18 of the plunger has an 
axial thickness of 0.12 inch. 
In this illustrative embodiment, the axial distance from the proximal face 
26 to the bridge segments 36 and 40 bounding respective slot segments 42 
and 44, is 0.165 inch. The axial height of the retention members 30 and 
32, as measured axially from the rear face 26 of the plunger body, is 
0.335 inch and the diameter of the lateral slot comprising slot segments 
42 and 44, is 1.04 inch. 
In the plunger of the present invention, so long as the central axis of the 
driving mechanism is coincident with the central axis of the plunger, 
subsequent rotation of the driving mechanism relative to the plunger will 
not result in disengagement of the head of the driving mechanism from the 
plunger. In other words, once the driving mechanism has been brought into 
initial engagement with the coupling structure of the plunger, any 
subsequent rotation of the head and shaft of the driving mechanism will 
not disengage the driving mechanism from the plunger. This retention 
feature is at odds with the "quick release" structure described in the 
forementioned Reilly et al U.S. Pat. No. 4,677,980, and achieves a 
significant advantage thereover, in that the occurrence of vibration, or 
inadvertent rotation of the head and shaft of the driving mechanism which 
may cause undesirable (e.g., premature) disengagement of the driving 
mechanism from the plunger in such prior art system, does not adversely 
affect the engagement of the coupling structure in the plunger of the 
present invention. 
While the invention has been described with reference to specific 
embodiments, aspects, and features thereof, it will be appreciated that 
the invention is not thus limited, in that apparent variations, 
modifications, and other embodiments will suggest themselves to those of 
ordinary skill in the art. Accordingly, the invention s to be broadly 
construed and regarded as encompassing all such alternative variations, 
modifications, and embodiments.