U.S. patent application number 11/073915 was filed with the patent office on 2006-04-13 for powerhead control in a power injection system.
This patent application is currently assigned to Liebel-Flarsheim Company. Invention is credited to Elaine Borgemenke, David M. Brooks, Frank M. Fago, Sean Lafferty, Gary S. Wagner.
Application Number | 20060079843 11/073915 |
Document ID | / |
Family ID | 35717442 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060079843 |
Kind Code |
A1 |
Brooks; David M. ; et
al. |
April 13, 2006 |
Powerhead control in a power injection system
Abstract
A dual head contrast media injection system performs a patency
check or test injection, determining flow rate and/or flow volume
from the programmed protocol. The tubing that connects syringes to
a patient shares only a short common section near to the patient.
Appropriate injection steps are taken to compensate for tubing
elasticity. A wireless remote control and a touch screen control
are provided, improving functionality and information delivery. The
display brightness is controlled based on the ambient light, and
the display panel includes a double swivel permitting
re-orientation. The orientation of the display may also be
controlled based on, e.g., the current step, the tilt angle of the
powerhead, or a manual control. Furthermore, the display is
customizable to identify the type of fluid (contrast, saline, etc.)
on either side of the injector, to provide matched color coding,
and to provide a folder/tab analogy for retrieving injection
protocol parameters.
Inventors: |
Brooks; David M.;
(Cincinnati, OH) ; Fago; Frank M.; (Mason, OH)
; Wagner; Gary S.; (Independence, KY) ;
Borgemenke; Elaine; (Morrow, OH) ; Lafferty;
Sean; (Taylor Mill, KY) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER
441 VINE STREET
CINCINNATI
OH
45202
US
|
Assignee: |
Liebel-Flarsheim Company
Cincinnati
OH
|
Family ID: |
35717442 |
Appl. No.: |
11/073915 |
Filed: |
March 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10964002 |
Oct 13, 2004 |
|
|
|
11073915 |
Mar 7, 2005 |
|
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|
Current U.S.
Class: |
604/151 ;
600/432 |
Current CPC
Class: |
A61M 5/14566 20130101;
A61M 5/16827 20130101; A61M 2205/505 20130101; A61M 2205/3362
20130101; A61M 39/10 20130101; A61M 2205/3561 20130101; A61M
5/14546 20130101; A61M 2205/3592 20130101; A61M 2205/3523 20130101;
A61M 2205/6081 20130101; A61M 2205/50 20130101; A61M 5/172
20130101; A61M 5/007 20130101 |
Class at
Publication: |
604/151 ;
600/432 |
International
Class: |
A61M 1/00 20060101
A61M001/00 |
Claims
1. A tubing assembly for a dual head contrast media injector system
comprising: first tubing providing a first fluid path between a
first syringe and a patient fitting, for a first fluid; second
tubing providing a second fluid path, separate from the first fluid
path, between a second syringe and the patient fitting, for a
second fluid; and the fitting configured to provide fluid
communication between each of the first tubing and second tubing
with a common fluid path for delivery of either the first or second
fluid to a patient.
2. The tubing assembly of claim 1, wherein: the first and second
tubing are connected for at least a portion between the first and
second syringes and the patient fitting while maintaining
separation between the first fluid path and the second fluid
path.
3. The tubing assembly of claim 1 wherein the patient fitting
includes a luer fitting.
4. The tubing assembly of claim 2 wherein the portion includes a
round outer tubing separated into two longitudinal chambers by a
way substantially bisecting an internal diameter of the round outer
tubing.
5. The tubing assembly of claim 2, wherein the portion includes two
substantially similar tubes connected together on a respective
outside edge of each tube.
6. A method within a dual head contrast media injector system,
comprising the steps of: connecting a first fluid container to a
patient fitting via first tubing providing a first fluid path
between the first fluid container and the patient fitting, for a
first fluid; connecting a second fluid container to the patient
fitting via second tubing providing a second fluid path, separate
from the first fluid path, between the second syringe and the
patient fitting, for a second fluid; and connecting the first fluid
path and the second fluid path with the patient fitting via a
common chamber in fluid communication with both the first and
second tubing; driving the first fluid container to deliver the
first fluid to the patient via the patient fitting; and
concurrently with driving the first fluid container, driving the
second fluid container to oppose reverse flow of the second fluid
as a result of pressures induced by driving the first fluid
container.
7. A method for performing a preliminary injection within a dual
head contrast media injector system comprising the steps of:
identifying a selected injection protocol; determining injection
parameters for fluid flows defined by the injection protocol; and
setting injection parameters for a preliminary injection based on
the determined injection parameters.
8. The method of claim 7 wherein the determined injection
parameters are selected from the group including identity of fluid
delivered, volume of fluid delivered and flow rate of fluid
delivered.
9. The method of claim 7 applied to the performance of a saline
patency check, further comprising the step of determining whether a
syringe holding saline has enough saline to perform the patency
check and the selected protocol.
10. The method of claim 9 further comprising, in the event of
insufficient saline to perform the patency check and the selected
protocol, a step selected from the group of terminating the patency
check or issuing a warning prior to performing the patency
check.
11. The method of claim 7, further comprising the steps of:
providing the determined injection parameters to an operator via a
user interface; receiving instructions back from the operator via
the user interface; and performing the patency check according to
the instructions.
12. A dual head contrast media injector system, the system
comprising: a processor for controlling operation of the injector
system; a memory coupled to the processor and storing a plurality
of injection protocols, each protocol including respective
injection parameters; a first head for driving injection of fluid
from a first syringe; a second head for driving injection of fluid
from a second syringe; the processor configured to selectively
perform a preliminary injection prior to performing an injection
protocol, wherein a flow rate for the preliminary injection is
based on injection parameters for a particular injection protocol
selected to follow said preliminary injection.
13. The dual head contrast media injector system of claim 12
wherein said first syringe contains saline fluid and said
preliminary injection is a patency check and utilizes saline fluid
from said first syringe of said injector system.
14. The dual head contrast media injector system of claim 13
wherein said patency check preliminary injection utilizes a flow
rate equal to a maximum flow rate of said particular injection
protocol.
15. The dual head contrast media injector system of claim 12
wherein said preliminary injection is a test injection and
initially utilizes the same head of said injector system as is
initially used by said particular injection protocol.
16. The dual head contrast media injector system of claim 15
wherein said test preliminary injection utilizes a flow rate equal
to an initial flow rate of said particular injection protocol.
17. The dual head contrast media injector system of claim 12
wherein said preliminary injection is separately enabled from said
particular injection protocol, said processor configured to
selectively not perform the preliminary injection upon instruction
from an operator.
18. The dual head contrast media injector system of claim 12
wherein said test injection may be selectively performed without
modification of said particular injection protocol.
19. The dual head contrast media injector system of claim 12
wherein said processor is configured to calculate fluid
requirements of said preliminary injection and said particular
injection protocol, and to generate an operator indication of
insufficient fluid.
20. The dual head contrast media injector system of claim 12
wherein said first and second syringes are connected by a common
length of tubing to a patient injection site, and said processor is
configured to perform injection steps as part of said preliminary
injection to fill said common length of tubing with a predetermined
one of saline, contrast and a mixture thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of U.S.
application Ser. No. 10/964,002, filed Oct. 13, 2005, entitled
POWERHEAD OF A POWER INJECTION SYSTEM, which is related to
co-pending application Ser. No. 10/964,003, filed Oct. 13, 2005,
entitled POWERHEAD OF A POWER INJECTION SYSTEM. The present
application is related to co-pending and concurrently filed
application Ser. No. ______, entitled POWERHEAD OF A POWER
INJECTION SYSTEM and the two divisional applications of application
Ser. No. 10/964,003, filed Oct. 13, 2005, entitled POWERHEAD OF A
POWER INJECTION SYSTEM. All of these applications are hereby
incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to contrast media injector
systems and, more particularly to improvements thereto.
BACKGROUND OF THE INVENTION
[0003] In many medical environments, a medical fluid is injected
into a patient during diagnosis or treatment. One example is the
injection of contrast media into a patient to improve CT,
Angiographic, Magnetic Resonance or Ultrasound imaging, using a
powered, automatic injector.
[0004] Injectors suitable for these and similar applications
typically must use a relatively large volume syringe and be capable
of producing relatively large flow rates and injection pressures.
For this reason, injectors for such applications are typically
motorized, and include a large, high mass injector motor and drive
train. For ease of use, the motor and drive train are typically
housed in an injection head, which is supported by a floor, wall,
or ceiling mounted arm.
[0005] The injection head is typically mounted on the arm in a
pivotal manner, so that the head may be tilted upward (with the
syringe tip above the remainder of the syringe) to facilitate
filling the syringe with fluid, and downward (with the syringe tip
below the remainder of the syringe) for injection. Tilting the head
in this manner facilitates removal of air from the syringe during
filling, and reduces the likelihood that air will be injected into
the subject during the injection process. Nevertheless, the
potential for accidentally injecting air into a patient remains a
serious safety concern.
[0006] In addition to the injection head discussed above, many
injectors include a separate console for controlling the injector.
The console typically includes programmable circuitry which can be
used for automatic, programmed control of the injector, so that the
operation of the injector can be made predictable and potentially
synchronized with operations of other equipment such as scanners or
imaging equipment.
[0007] Thus, at least part of the injection process is typically
automatically controlled; however, the filling procedure, and
typically some part of the injection procedure, are normally
performed by an operator, using hand-operated movement controls on
the injector head. Typically, the hand-operated movement controls
include buttons for reverse and forward movement of the injector
drive ram, to respectively fill and empty the syringe. In some
cases, a combination of buttons is used to initiate movement of the
ram or to control ram movement speed. The injector head also
typically includes a gauge or display for indicating injection
parameters to the operator, such as the syringe volume remaining,
for the operator's use when controlling the injector head.
Unfortunately, operators have found it cumbersome to use the
hand-operated movement buttons and to read the injector head gauges
and displays, for several reasons, not the least of which is the
necessary tilting of the injector head between the upward, filling
position to the downward, injection position, changing the
positions of the hand-operated movement buttons relative to the
operator, and at some tilt angles rendering the gauges or displays
difficult to read.
[0008] In many applications, it is desirable to use an injector
with multiple different syringe sizes. For example, it may be
desirable to use a smaller syringe for pediatric use than for adult
use, or where a particular procedure requires a smaller volume of
fluid. To facilitate the use of different syringe sizes, injectors
have been constructed with removable faceplates, where each of the
various faceplates is configured for a particular syringe size.
Typically, the injector is able to adjust injection parameters by
detecting which faceplate is mounted to the injector, for example
using a magnetic detector mounted to the front surface of the
injector housing to detect the presence or absence of a magnet in
the faceplate. Unfortunately, the necessity of incorporating a
magnetic detector into the outer housing of the injector head
increases the complexity and expense of manufacturing the injector
head.
[0009] Recently, one development in power injectors has been the
introduction of dual headed injectors, that is, an injector with
two drive systems and mountings for two syringes. The software for
the injector provides for independent control of these drive
systems using both manual controls and programmed injection
routines in response to a stored sequence. Such dual headed
injectors allow multiple fluids to be injected during a sequence
without changing a syringe or other equipment.
[0010] Regardless of the benefits of current power injector
systems, whether single head or dual head, improvements and
advances in this field continue to be desirable goals and will
ensure that such equipment becomes easier to use, increase in
functionality, and become more reliable and efficient in
operation.
SUMMARY OF THE INVENTION
[0011] Accordingly embodiments of the present invention relate to
improving power injectors that are used to inject contrast media
and other fluids in a patient or animal.
[0012] One aspect of the present invention relates to a display,
such as the console or powerhead, of the injector system
accommodating different ambient light conditions. For example, the
display elements such as LCD screens and LED lights can be
controlled such that their relative brightness levels are dependent
on the ambient light conditions. Operator override functionality
can be provided as well.
[0013] Another aspect of the present invention relates to a touch
screen interface for the powerhead of the contrast media injector
system. The touch screen display can be driven from software so
that it is configurable and not dependent on hardwired switches,
LED indicators or 7-segment displays. The powerhead can therefore,
provide the same functionality as the console display, thereby
eliminating the console if desired. In addition to more data and
more controls being available at the powerhead, help instructions
and other contextual assistance can be provided to help the
operator run the equipment.
[0014] Yet another aspect of the present invention relates to a
display for a dual head injector system that displays information
about both syringes and fluid simultaneously. The display of the
powerhead is color-coded so that information about one syringe is
visually distinct from information about the other syringe. For
additional ease-of-use conventional color associations can be used
such that a purple display refers to contrast media, yellow refers
to saline, and black refers to air.
[0015] In accordance with another aspect, additional ease-of-use
features are included in the display of stored protocol
information, by use of a folder-tab analogy for managing numerous
stored protocols.
[0016] Still a further aspect of the present invention relates to a
remote controlled powerhead. A conventional powerhead drive
mechanism and syringes are augmented to include a receiver for
receiving a control signal from a remote device. In response to the
control signal, the powerhead operates the syringe ram
appropriately.
[0017] One additional aspect of the present invention relates to a
dual head injector that utilizes tubing in which the fluid paths
remain separate until substantially at the patient. By utilizing
this type of V-tubing, the elasticity of the fluid delivery
components (e.g., syringe, tubing, etc.) can be easily accommodated
and there is reduced lag time in administration of a desired fluid
to a patient.
[0018] One more aspect of the present invention relates to
performing a patency check using a dual head injector system. In
accordance with this aspect of the invention, a saline injection is
enabled and performed prior to execution of the stored protocol of
an injection, at nearly the same flow rate and volume as the
upcoming media injection, to ensure that extravasation does not
occur. This method may be implemented in software that retrieves
the flow rate and other information about a selected protocol and
controls the saline patency injection based on those
parameters.
[0019] A related aspect of the present invention relates to a test
injection feature. In accordance with this aspect, a test injection
is performed, initially using the same fluid and initial flow rate
as an stored protocol of an injection, to enable the user to
determine the suitability of that flow rate and also determine the
timing associated with the injection such as the delay time for the
injected fluid to reach an area of interest of the patient.
[0020] It will be appreciated that both the test injection and
patency check have common characteristics that distinguish them
from normal programming of an injector. Specifically, both are an
injection that is separately enabled from the stored injection
protocol to be administered to the patient, and both are separate
from the stored injection protocol, i.e., they may selectively be
conducted, or not, at the operator's discretion. Thus, the operator
need not perform a patency check or test injection, but has the
ready option to do so without altering a stored injection protocol.
While the patency check and test injection are thus functionally
and operationally separated from a stored protocol, they are
nevertheless programmatically controlled injections, and use
parameters that may be derived from the later, stored injection
protocol, e.g., the flow rates or use of fluids is modeled after
the planned injection. Because the test injection and patency check
are programmatically controlled injections, they may accurately
mimic the stored injection protocol in the relevant aspects,
without the effort of human involvement and the possibility for
human error. Furthermore, because they are programmatically
controlled, it is possible to calculate the fluid requirements of
the patency check or test injection, which may be combined with the
planned subsequent injection to ensure that there is sufficient
injectable fluid available, thus ensuring that time is not lost
re-filling the injector (which may involve re-entering the scanning
room after it has been sealed) as may occur if a patency check or
test injection is manually performed. Finally, in the context of a
dual headed injector, a test injection or patency check, because it
is programmatically controlled, may include functionality to
automatically return the injector tubing to an appropriate initial
state, e.g., a state in which the tubing is filled with saline or
contrast media, or a mixture, as the operator and physician prefers
for the imaging procedure.
[0021] Another aspect of the present invention relates to a mount
for a display screen on an injector that permits the screen to be
positioned flush with a surface of the injector or to be moved to a
position extending from the surface of the injector. In the
described embodiment the mount provides a double swivel permitting
the screen to be swivelled away from the injector surface and
pivoted about its axis, thereby facilitating visibility of the
screen for numerous possible injector and operator positions.
[0022] A related aspect of the present invention involves
programming of the powerhead to orient the content on the display
automatically to an appropriate orientation and/or re-size that
content based upon the current step in an injection sequence. This
aspect may also be combined with sensors relating to the
orientation of the display. For example, if a sensor is included in
the mounting mentioned above, the display may be automatically
re-oriented in response to tilting of the display away from the
injector. Further, if an Earth gravitation sensor is included in
the injector, the display may be automatically re-oriented in
response to tilting of the injector relative to gravity, e.g.
tilting upward for filling and downward for injecting.
[0023] A further aspect of the present invention relates to an
injector powerhead for injection from first and second syringes,
which may contain fluids of two different types, in which the
injector permits an operator to identify the type of fluid
contained in the first or the second syringe, thus enabling the
operator to use either syringe location for either type of fluid,
at the operator's discretion.
[0024] It will be appreciated that principles of the present
invention are applicable to the injection of contrast media into a
patient to improve CT, Angiographic, Magnetic Resonance or
Ultrasound imaging, or any other application involving injection of
fluids using a powered, automatic injector.
[0025] The above and other objects and advantages of the present
invention shall be made apparent from the accompanying drawings and
the description thereof.
BRIEF DESCRIPTION OF THE DRAWING
[0026] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and, together with a general description of the
invention given above, and the detailed description of the
embodiments given below, serve to explain the principles of the
invention.
[0027] FIG. 1A illustrates a power injector system according to the
principles of the present invention, and FIG. 1B illustrates the
components of the powerhead of that system.
[0028] FIG. 2 illustrates a block diagram of a display system that
controls the brightness of its display elements based on ambient
light conditions in accordance with the principles of the present
invention.
[0029] FIG. 3 depicts a flowchart of an exemplary algorithm useful
with the system of FIG. 2.
[0030] FIGS. 4A-4E illustrate a series of exemplary interface
screens for a touch-screen display of a powerhead in accordance
with the principles of the present invention.
[0031] FIG. 4F illustrates a swivel mount for an injector powerhead
display screen in accordance with principles of the present
invention.
[0032] FIGS. 5 and 6 illustrate an exemplary powerhead display
screen for a dual head system that correlates tubing color and
display icons and colors with each other in accordance with the
principles of the present invention.
[0033] FIG. 7 illustrates a remote controlled powerhead in
accordance with the principles of the present invention.
[0034] FIG. 8 illustrates exemplary V-tubing to connect a dual
injector head system to a patient in accordance with the principles
of the present invention.
[0035] FIG. 9 illustrates an exemplary end fitting for the tubing
of FIG. 8.
[0036] FIG. 10 illustrates an exemplary cross-section of the tubing
of FIG. 8.
[0037] FIG. 11 depicts a flow chart of an exemplary method to
perform a patency check with a dual head injector system.
[0038] FIG. 12 depicts a flow chart of an exemplary method to
perform a test injection with an injector system.
[0039] FIG. 13 depicts an exemplary display screen for a dual head
injector system used to perform a test injection method.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0040] Referring to FIG. 1A, an injector 20 in accordance with the
present invention includes various functional components, such as a
powerhead 22, a console 24 and powerpack 26. Syringes 36a and 36b
are mounted to the injector 20 in faceplates 28a and 28b of the
powerhead 22, and the various injector controls are used to fill
the syringe with, e.g., contrast media for a CT, Angiographic or
other procedure, which media is then injected into a subject under
investigation under operator or pre-programmed control.
[0041] The injector powerhead 22 includes a hand-operated knobs 29a
and 29b for use in controlling the movement of the internal drive
motors engaged to syringes 36a and 36b, and a display 30 for
indicating to the operator the current status and operating
parameters of the injector. The console 24 includes a touch screen
display 32 which may be used by the operator to remotely control
operation of the injector 20, and may also be used to specify and
store programs for automatic injection by the injector 20, which
can later be automatically executed by the injector upon initiation
by the operator.
[0042] Powerhead 22 and console 24 connect through cabling (not
shown) to the powerpack 26. Powerpack 26 includes a power supply
for the injector, interface circuitry for communicating between the
console 24 and powerhead 22, and further circuitry permitting
connection of the injector 20 to remote units such as remote
consoles, remote hand or foot control switches, or other original
equipment manufacturer (OEM) remote control connections allowing,
for example, the operation of injector 20 to be synchronized with
the x-ray exposure of an imaging system.
[0043] Powerhead 22 is mounted to a wheeled stand 35, which
includes a support arm for supporting powerhead 22 for easy
positioning of powerhead 22 in the vicinity of the examination
subject. Console 24 and powerpack 26 may be placed on a table or
mounted on an electronics rack in an examination room. Other
installations are also contemplated however; for example, powerhead
22 may be supported by a ceiling, floor or wall mounted support
arm.
[0044] Referring to FIG. 1B, details of the powerhead 22 can be
seen. In FIG. 1B, specific content can be seen on touch screen
display 30 illustrating the two syringes and their status, as well
as a protocol of injection steps to be used in conjunction with
those two syringes.
[0045] Although the powerhead 22 discussed herein is a dual head
injector, embodiments of the present invention explicitly
contemplated single head injectors as well.
[0046] Referring to FIG. 2, an optical sensor 262 is included on
one of the internal circuit boards within the injector powerhead
housing 30 and is situated near a window 263 or other opening that
allows it to detect ambient light levels. Such an optical sensor
262 would typically be an analog device that converts the light
level detected into a voltage or current signal. After being
converted via an analog-to digital converter (ADC), this signal
could then be used by a microprocessor to raise or lower the
brightness levels of the display. The control algorithm for
correlating detected light levels with a display brightness setting
may be selected according to a variety of methods. For example, the
brightness and detected light levels may be linearly correlated.
However, if the optical sensor 262 has a non-linear detection curve
then an appropriate correlation formula can be used to change the
brightness levels. Additionally, the brightness changes might occur
at a limited number of predefined steps or, alternatively, cover a
nearly-continuous spectrum of brightness settings. Thus, one of
ordinary skill would recognize that within the scope of the present
invention, there are a variety of functionally equivalent methods
for adjusting the brightness of the power injector's display based
on the ambient light conditions.
[0047] The methods of adjusting the brightness vary with the type
of display. For example, brightness of LED's 270 on the powerhead
may be adjusted by adjusting the duty cycle of the signal driving
the LED. An LCD driver circuit 268, on the other hand, could use a
pulse-width modulated signal, or a DC voltage level, to control its
brightness setting. The intensity control circuits 264, 266,
therefore, may be different depending on the type of display (e.g.,
268, 270) being controlled.
[0048] An exemplary algorithm for controlling the display of either
the powerhead 30 or the console 32 is depicted in the flowchart of
FIG. 3. The sensors and control circuitry are conventional in
nature and one of ordinary skill will recognize that a variety of
functionally equivalent circuits could be used to generate the
appropriate control signals. In step 302, a sensor is used to
detect an ambient light level in the environment where the injector
equipment is being used. Then, in step 304, this detected level is
converted into a brightness setting for the display. This
conversion process may include simple analog-to digital circuitry
or use a microprocessor with accessible memory that correlates a
detected level to a display brightness according to stored settings
in the memory. The conversion process may utilize operator inputs
to override default behavior or operate automatically without
considering operator inputs. Ultimately, in step 306, the display
hardware is controlled according to the brightness setting. The
LEDs of a particular display may have their own control circuitry
that operates them according to the brightness setting, and an LCD
screen or other display may have its own separate control circuitry
operating it appropriately.
[0049] Conventional powerheads for injectors have included only
enough controls to implement a limited amount of functionality as
compared to the console of the injector system. The powerhead
controls were typically limited to moving the syringe ram and
enabling, starting and disabling an injection protocol. The
information displayed by the powerhead during an injection was also
limited in nature. The console on the other hand has a larger
display and more controls that provided additional functionality.
Protocol selection and entry, saving and editing injection and
syringe parameters, patient contrast volume, injection history,
injection phase information and delays, syringe parameters,
interface information, instructions and help screens, etc. are all
functionality typically provided through the console but not the
powerhead.
[0050] In contrast to the conventional injector system, as just
described, embodiments of the present invention include a powerhead
that does not require a console. Through screens on the powerhead
an operator is able to control everything involved in an injection
sequence. As one advantage of such a system, the up-front cost of
the injector without a console is reduced. Also, the ability of the
display of the powerhead to display more and better information,
help screens and other functions allows an operator to more
efficiently operate and to more quickly learn how to operate the
powerhead via a touch screen. Instead of the controls on the
powerhead being hard-wired switched and buttons, the display could
be a touch screen that presents a user interface that is easily
reconfigurable and more robust.
[0051] Referring to FIGS. 4A-4F, an injection protocol will be
described from the operator's perspective. However, unlike
conventional injector systems the interface screens described with
respect to these figures are provided by a touch screen display 30
at the powerhead. The main operating screen is illustrated in FIG.
4A. Box 200, which is associated with an iconic representation 201
of the powerhead, identifies the current volume of contrast media
in the A syringe. Box 202, which is associated with an iconic
representation 203 of the syringe, identifies the current volume of
contrast media in the B syringe. Box 204 identifies the pressure
limit pre-selected by the operator for the procedure, and box 206
identifies a scan delay (in seconds), which is the delay from the
time the operator initiates an injection (either with the hand
switch, a key on the console or a button on the powerhead) until
the x ray or magnetic scan of the subject should begin (at the end
of this delay, a microprocessor within the powerhead produces a
tone indicating to the operator that scanning should begin;
alternatively, scanning could be automatically initiated by a
suitable electrical connection between the scanner and injector).
Box 207 identifies an inject delay (in seconds), which is a delay
from the time the operator initiates an injection as noted above,
until the injection as descried by the protocol will begin, thus
allowing time for the scanner to be initiated before flow of
contrast. In the illustrated situation, the syringe A contains 158
ml of fluid, 73 ml of which will be used by the currently selected
protocol, syringe B contains 158 ml of fluid, 83 ml of which will
be used by the currently selected protocol, the pressure limit is
20 psi and there is no scan or inject delay.
[0052] In the display illustrated in FIG. 4A, button 208 may be
used to alter the orientation of the display. Specifically, as seen
in FIG. 4B, by pressing the screen at this button, the display may
be reversed on the screen to thereby facilitate the use of the
injector in multiple possible orientations.
[0053] As shown in FIG. 4A, a protocol comprises a number of
phases; during each phase the injector produces a pre-programmed
flow rate to output a pre-programmed total fluid volume. The
illustrated protocol has only two phases; however, other protocols
which can be selected by the operator have multiple phases. The
user can select protocols, enable an injection, and otherwise
navigate through display screens by pressing the touch buttons of
the display 30.
[0054] Regions 212 of the display identify the flow rates for the
phases of the current protocol, and regions 214 identify the
volumes for those respective phases. The user may alter these
parameters by pushing any of these regions, to move thereby to a
protocol parameter entry screen, shown in FIG. 4C. On this screen
the user may change and store the flow, volume and inject and scan
delay values for the current protocol by pressing each of these
values as displayed on the screen, and then moving the slide bar
control shown in region 216.
[0055] From FIG. 4A, the operator may also enter a manual control
display by pressing on the iconic representation of a syringe 201
or 203. At the manual control display, shown in FIG. 4D, the
operator may manually control plunger movement. At this screen, the
iconic representation of the selected syringe in box 200 of FIG. 4A
is replaced with a fill-expel bar display 220. By pressing on this
fill-expel bar display the motor drive for the selected syringe may
be caused to advance or retract thereby to fill or expel fluid from
that syringe.
[0056] Referring now to FIG. 4E, the display of stored injection
protocols can be described. Through the memory button 218 in FIG.
4C, the protocol memory display seen in FIG. 4E may be viewed,
where protocols may be stored and retrieved. Protocol memories are
known in the art, however, one difficulty with the display of
protocols in the prior art has been the limited space available to
display a representation of a large number of protocols. For
example, as seen in FIG. 4E, only eight protocols can be adequately
represented on the display, each associated with a customized named
button 222 in the left hand column, and parameters displayed in the
right hand column. To overcome this difficulty, in accordance with
principles of the present invention, five graphical "tabs" 224 are
also provided on the display. Each tab is associated with different
set of eight protocol storage locations 222, and the operator may
move quickly between the tabs by pressing upon the tabs 224. In
this way, forty protocols may be stored and quickly retrieved while
continuing to provide sufficient information regarding each
protocol on the screen. The tabs 224 may bear numbers or may have
user-configurable names as are used with protocols, so that, for
example, one tab may contain protocols used with each of several
technicians or physicians.
[0057] The above description of an interface for an exemplary
powerhead identifies a number of specific features; however, the
principles of the present invention apply to a variety of other
touch-screen features that may also be provided. Indeed, a touch
screen provides sufficient flexibility in the interface that
certain embodiments of the present invention contemplate providing
a complete interface at the powerhead such that a console is no
longer needed for a power injection system.
[0058] U.S. Pat. No. 5,868,710, commonly assigned to the present
assignee, is incorporated by reference in its entirety. That patent
discloses a display screen for an injector powerhead that
automatically detects the orientation of the powerhead and flips
the output of the display screen accordingly so that it is more
readily readable to an operator. Embodiments of the present
invention advantageously include such functionality for the
augmented display screen as described above.
[0059] Referring to FIG. 4F, in a further embodiment consistent
with principles of the present invention, the display screen 30 may
be mounted to powerhead 22 by a swivel mount 238, permitting the
screen 30 to be positioned flush with a surface of the injector
powerhead 22, or to be tilted from the surface of the powerhead 22
as shown by arrows 240, and optionally subsequently pivoted about
mount 238 as shown by arrow 242, thus permitting screen 30 to be
optimally positioned to permit control and operation of injector
powerhead 22 for any number of various possible injector and
operator positions.
[0060] The current orientation of the display as shown in FIG. 4F
may be detected by a sensor incorporated within the injector, so as
to re-orient the display appropriately as the display is swivelled
relative to the injector head. Such a feature may be used in
conjunction with the use of a tilt sensor as described in the
above-referenced U.S. Patent to enable a rich interface selecting
an appropriate initial screen display orientation. Furthermore,
screen display orientation may be responsive to the current status
of the injector in an injection sequence, e.g., one orientation may
be used when in a manual control mode as shown in FIG. 4D (when the
injector is typically tilted upward for filling) and a second
orientation used when performing an injection protocol such as
shown in FIG. 4A (when the injector is typically tilted downward
for injecting).
[0061] It will be appreciated that there are other possibilities
for configuring the injector powerhead display in response to
injection steps and/or tilt angle of the injector. For example,
during an actual injection sequence when the injector is armed,
tilted down, and an injection is enabled, the technician using the
injector is often in a separated control room far from the injector
powerhead. Under such circumstances it may be beneficial to
display, in a very large font oriented for an injector tilted
downward, the current injector flow rate, volume and/or pressure,
potentially together with color coded, blinking or flashing regions
or fonts, or graphical iconography, to indicate the injector status
in a manner that will be visible by the technician from a great
distance, so that the technician may watch the patient during the
procedure and still have basic feedback on the operation of the
injector without looking to the console.
[0062] If the console is included with the contrast media injector
system, then the powerhead is a secondary control interface for the
contrast media injector system. The computer, memory and executable
applications that are typically a part of the console would
continue to be a part of the console and the powerhead would simply
communicate with the console. If, however, the console were not
included in the contrast media injector system then the powerhead
or some other component would need to be included that possessed
the computational and storage capabilities to provide such
functions as on screen textual help, multiple touch screens that
are configurable to provide a clear user interface, protocol
setting and setup information, etc. that was typically provided by
the console.
[0063] Turning to a different topic, injector powerheads have
conventionally included a single injecting head but dual head
injectors are becoming more prevalent as well. Typically, one
syringe is used to deliver saline and the other is used to deliver
contrast media (although other fluids are used as well). Features
that make these injectors safer, easier, and faster to use are
desirable; especially those that can be performed automatically by
control software within the powerhead.
[0064] The dual head injector powerhead 22 with display 30
discussed above, is depicted schematically in FIG. 5 along with
tubing and connections thereto. Each syringe 36a, 36b is connected
to respective tubing 506, 508 that eventually joins into a common
tubing portion 510 that ends at a fitting 512 (e.g., Luer fitting)
coupled to a catheter that delivers fluid to a patient.
[0065] The tubing 506, 508, may be colored to indicate the contents
of the tubing or it may be clear. In either case, the display 30
includes graphical information for an operator that indicates the
fluid that is being delivered by each syringe 36a, 36b. An
exemplary display is depicted in FIG. 6 that may be part of the
display screen 30. One graphical image of a syringe 602 and tubing
606 is provided on the left while another graphical image of a
syringe 604 and tubing 608 is provided on the right. As shown, a
respective fluid 610, 612 is shown in each syringe 602, 604. In
particular, as an injection protocol progresses, the display 600
changes to reflect the fluid level changes and to reflect which
fluid is being delivered to the patient (portion 609 of FIG.
6).
[0066] To assist the operator in recognizing what fluid is being
delivered from which syringe, the display 600 color-codes the
contents of each syringe and tubing to identify the fluid. For
example, a clear color on the display 600 may indicate that air is
in a particular syringe and tubing. Coloring the fluid "red" on the
display 600 may indicate that contrast media is in that syringe,
while a different color (e.g., blue) indicates the presence of
saline.
[0067] Such a colored display could also be used on a single head
injector to indicate the status of different automatic functions.
For example, this type of graphical display including color
information allows an operator to easily and quickly determine if a
syringe is full of air; when an empty syringe and tubing have been
properly filled and purged, or when a pre-filled syringe has been
purged properly.
[0068] It will be noted that dual-head injectors have typically
required an a priori selection of saline and contrast locations on
the two heads, for example, for consistency with the displays of
the injector, a syringe containing saline fluid would be required
to be attached to the first side of the injector and a syringe
containing contrast media would be required to be attached to the
second side of the injector. An aspect of the present invention is
to permit configuration of the injector such that displays
presented on the injector can be made consistent with any
combination of fluid types on the injector. Specifically, an
injector in accordance with the present invention permits the
operator to define the type of fluid, and color coding thereof, on
each of the A and B sides of the injector. Thus, the operator may
use the injector with syringes containing fluids of any two
arbitrarily selected types, or with fluids of the same types, and
correspondingly configure the injector and its displays to match
the chosen application. Any arbitrarily selected fluid type may
also be used with any arbitrarily selected syringe size. This
enables the operator to use either syringe location for any syringe
size and any type of fluid, at the operator's discretion, without
being subjected to confusingly inconsistent displays from the
injector. Alternate color-coded tubing sets may also be provided
for matching to the selected injector displays.
[0069] In the dual head powerhead of FIG. 5, two different fluid
tubes are coupled with the injector powerhead 503 but, typically,
there is only one fluid entry point at the patient. Thus, the two
fluid tubes eventually merge together between the syringes and the
patient. In the past, Y-tubing has often been used in which the
separate tubes merge relatively near the syringes so that a single
fluid tube exists for the majority of the tubing. The inherent
elasticity of syringes allows back flow to the non-driven syringe
during a pressure injection. Unless precautions are taken with
common Y-tubing, a typical injection producing 150 psi will allow
about 5 ml of the contents of the driven syringe to be pushed into
the undriven side where it will contaminate that side. In the past,
check valves have been used to prevent this, but such a solution
introduces its own set of problems.
[0070] Also, Y-tubing has a lag time between supplying the two
different fluids. In other words, the entire contents of the
Y-tubing shared portion must be flushed of one fluid before a
second fluid can be delivered to the patient. While methods exist
for addressing this issue, these methods require additional
activity and input by an operator that complicates and lengthens an
injection routine.
[0071] FIG. 8 depicts a V-tubing arrangement in which the junction
between the two tubings is relatively close to the patient's end.
Two syringes 802, 804 are used to deliver two different fluids to a
patient. The syringe 804 is coupled with an initial portion of
tubing 806 and the syringe 802 is coupled with a separate portion
of tubing 810. Although these portions of tubing 806, 810 merge
externally, they retain separate flow paths through a common
portion of tubing 811. The tubing 811 terminates at the patients
end with a fitting 812 to deliver one of the fluids.
[0072] The cross-section of an exemplary fitting is depicted in
FIG. 9. The tubing 811 splits into separate portions 902, 904 that
both couple to the fitting 812. In particular, the portions 902,
904 couple to a central cavity 816 such that fluid directed through
the tubing sections 902, 904 are delivered to the cavity 816. From
the cavity 816, fluid is expelled from the fitting 812 through an
opening 814.
[0073] Even though the tubing 811 appears externally to be a single
fluid tube, the principles of the present invention maintain the
separate fluid paths until the tubing 811 substantially reaches the
fitting 811. FIG. 10 depicts exemplary cross-sections that could be
used to implement tubing 811. The cross-section 1002 is generally
circular in nature with two passageways separated by a vertical
wall. The cross-section 1004 is similar to two circular tubes
attached along a common side. Each cross section may be formed from
co-extruded plastic or by similar means and can be color coded to
help identify the intended contents of the tubing.
[0074] As mentioned, a typical power injector system includes
inherent elasticity due to compression of the syringe plunger and
the expansion of the syringe barrel. The shape and size of the
plunger affects this amount of elasticity as well. According to
certain embodiments of the present invention, the un-driven side of
the powerhead may be driven to a sufficient displacement to prevent
the movement of fluid into the tubing on the undriven side due to
elasticity. The amount of amounts of fluid to drive from an
un-driven syringe will be a function of the pressure used on the
driven size and the type of syringe in use. In a closed-loop
approach, a measure of pressure and/or fluid flow in the undriven
sized may be used to perform closed-loop control of the ram on the
undriven side to prevent flow into the undriven side due to
elasticity. In an open-loop approach, measured values of typical
elasticity may be used to drive an appropriate amount based upon
the pressure on the driven side. For example, when a 125 ml syringe
having a flat plunger face sold by the present assignee is driven
at 50 PSI, the undriven side should be driven approximately 1.72 ml
to compensate for movement of fluid due to elasticity. With this
syringe, at 100 PSI, the driven amount is 2.28 ml, at 150 PSI, 3.45
ml, at 200 PSI, 4.32 ml, at 250 PSI, 5.37 ml, and at 300 PSI, 6.78
ml. Other syringes will have other characteristic values at various
pressures. In a combined open/closed loop approach, the initial
displacement applied to the undriven side upon initiation of the
injection may be obtained from measured typical values, after which
a closed-loop control may be initiated to maintain an equilibrated
pressure between the driven and undriven sides and/or zero flow
rate on the undriven side.
[0075] Previous injector powerheads for contrast media injectors
have included mechanisms to move the motor powered syringe ram back
and forth automatically. These mechanisms have included levers,
membrane key pads, push button or toggle switches, magnets and
Hall-effect sensors, etc. In all such instances, though, these
mechanism were part of the powerhead of the injector.
[0076] Embodiments of the present invention relate to a remote
control powerhead in which the control means for effecting movement
of the syringe ram is locate remotely from the powerhead. Such a
remote control will allow an operator greater flexibility in
location during certain injector operations and protocols.
[0077] FIG. 7 illustrates one simple remote control 710 that is
sized to fit in an operator's hand. The remote control emits a
signal from a transmitter 712 that is received at a receiver 708 at
the powerhead. Within the powerhead, the signal is converted for
use by the motor control circuitry 702 to effect movement of the
syringe ram 706 through the motor drive 704. The motor drive 704
and syringe ram 706 operate similar to conventional powerheads
except that in addition to receiving input from local controls, the
input from the receiver 708 is considered as well. The exemplary
remote control 710 includes two buttons 714, 716. One button 714
extends the ram 706 towards the front of the syringe and the other
button 716 retracts the ram 706 from the front of the syringe. This
particular remote control 710 permits one-handed operation because
of its size and button placement.
[0078] One of ordinary skill will recognize that such a remote
control 710 can include a variety of functions, have a variety of
physical form factors, and include various numbers of buttons and
knobs, without departing from the scope of the present invention.
For example, a potentiometer (linear or rotary) may be used to
remotely control the ram movement at a fixed speed. Alternatively,
a pressure sensitive switch may be utilized that permits control of
the ram movement but changes its speed depending on the pressure
supplied.
[0079] The frequency at which the remote control and the powerhead
communicate is not a material constraint of the present invention
which explicitly contemplates UHF, VHF, RF, infrared, ultrasonic,
etc. as exemplary communication modes. Because the remote control
may have a tendency to be separated from the general vicinity of
the powerhead, a physical tether 720 may be provided that limits
the removal of the remote control from the powerhead. Accordingly,
this tether may also act as a communications path in certain
embodiments such that the remote control is not a wireless device
but is coupled to the powerhead via a physical cable.
[0080] During venous procedures utilizing power injectors, the
contrast media or imaging agent is sometimes unintentionally
injected into the tissue surrounding a patient's vein. This is
generally referred to as extravasation and is considered a hazard.
It is commonly caused by the operator missing the patient's vein
entirely while inserting a catheter; piercing through the vein into
surrounding tissue; or injecting at a flow rate that punctures the
wall of the vein.
[0081] There are common techniques used by operators to detect or
prevent extravasation but these are not always 100% effective. When
using a dual head injector, one common technique is to perform a
patency test by first injecting saline into a patient's vein while
observing for skin swelling. This may be done manually or as part
of a stored protocol. While effective in some cases, the saline may
not be injected at a flow rate and volume that adequately simulates
the injection protocol. Thus, the actual imaging agent injection
may extravasate even if the saline injection did not.
[0082] Embodiments of the present invention relate to a dual head
power injector that includes in its software, one or more routines
that assist an operator in selecting an optimum flow rate and
volume during the saline injection test portion of a patency test.
The patency test interface screen will suggest to the operator flow
rate and/or volume values that are based on the selected protocol
that provide a simulation that is substantially similar imaging
injection that is to follow. This additional functionality may be
included via a separate dedicated display on the powerhead, or
console, or may be one of the many menu screens typically presented
to an operator through the general interface screen. Also, the
software may automatically set the flow rate and volume or permit
the user to set, or modify, the values after seeing the suggested
values. Certain safeguards may be included such that a patency
check may not be performed until a protocol is enabled or until a
manual purge has been completed. Also, the patency check may
include a verification that enough saline remains available before
proceeding with the patency check.
[0083] In general, the principles of the present invention can be
implemented according to an exemplary algorithm depicted in the
flowchart of FIG. 11. In step 1102 an injection protocol is
selected and enabled. Before the protocol is performed, however,
the operator may want to perform a patency check, and activates the
patency check (step 1108). In an exemplary embodiment, the user
indicates desire to perform a patency check by pressing and holding
the expel button for the saline syringe for a given period of time,
although numerous other interface methodologies may be used to
permit the user to initiate a patency check. As shown in the flow
chart, the specific methodology discussed here requires that the
operator press a button for more than the threshold time, thus
ensuring that a patency check is not unintentionally initiated. If
the button is released too early, no patency check is performed,
but may be re-initiated as illustrated at step 1108.
[0084] In the described embodiment, the software performs an
optional check in step 1110 to determine if adequate fluid exists
to perform the patency check and the selected protocol. If there is
not adequate fluid, the process stops. However, if there is
sufficient fluid, then the patency check may be executed in step
1112.
[0085] Based on the selected protocol, an operator is presented
interface options to set up the patency check. These options derive
from the existing protocol or from settings made by the user. As
seen at step 1114, a volume for the patency check is derived from a
factory default, or a historical volume used for previous patency
checks. As shown at step 1116, the user has the opportunity to
change the volume if desired. If, so, then the volume value is
changed in step 1118. As seen at step 1120, a flow rate is also
selected for the patency check. Again, this could be based on the
protocol, a default value or historical data. In the described
embodiment, the default flow rate is selected to be the maximum
flow rate on the "A" or "B" sides of the injector, so that the
patency check verifies the lack of extravasation at the largest
flow rate that will be required. Here again, the user is provided
the option of changing the patency check derivation in step
1122--if desired the user may choose the "A" side flow rate or
maximum "A" side flow rate, or the "B" side flow rate or maximum
"B" side flow rate, in step 1124.
[0086] Once the user has been presented with patency check settings
(e.g., in a setup screen displayed immediately after step 1110),
the user may execute the patency check in step 1112. Assuming no
extravasation is evident, the operator would typically proceed to
enable the protocol in step 1102, at which point the injector
awaits a "start" indication from the operator in step 1104, upon
which the protocol is executed in step 1106. If there is
extravasation seen during the patency check, this may be remedied,
and another patency check performed.
[0087] Referring now to FIG. 12, a test injection methodology can
be described. To perform a test injection, in step 1202 the
operator selects a test injection when configuring an injection
protocol, such as by depressing the "test injection" key in the
protocol setup screen shown in FIG. 6. Once a test injection is
selected, the test injection/protocol setup screen is displayed, as
shown in FIG. 13. On that screen, it can be seen that in addition
to the injection protocol parameters displayed as shown in FIG. 6,
test injection parameters are displayed in an area 1302. These
parameters include parameters identifying the flow rate and total
volume of a test injection.
[0088] As seen in FIG. 12, the values for the flow rate and volume
of a test injection are generated using the stored information and
protocol parameters that have already been set by the user.
Specifically, as seen at 1208, a factory default value (e.g., 10
ml) may be initially used as the volume of a test injection, or the
volume used in a prior test injection may be used. The volume
setting created is a default, but can be changed. As seen in FIG.
13 the test injection flow rate and volume settings are shown in
buttons on the screen, which may be touched to enable adjustment
with a slider bar or other graphical control as is shown in FIG. 6.
Thus, in step 1210 of FIG. 12 the user may take action to change
the volume settings and in step 1212, make a desired change to
generate the final volume settings for the test injection.
[0089] Similarly, in step 1214, a default flow rate is created for
the test injection based upon the initial flow rate and side ("A"
or "B") used in the already programmed protocol. These values are
defaults and, as before, in step 1216 the user may take action to
change the flow rate in step 1218. After making changes or
accepting the defaults, the flow rate settings are determined.
[0090] In addition to the above adjustments, the user may change
the head used by touching the button in the "Side" column on the
graphical display, as is done in the interface of FIG. 6 when a
test injection is not selected.
[0091] Initially, a test injection may include only injection from
one side of the injector, e.g., the "A" side or a side that has
been identified as carrying contrast media. However, a test
injection may also use both sides, e.g., to inject a bolus of
contrast media followed by a saline flush so as to create a
"packet" of contrast media surrounded by saline fluid. Or the test
injection may be done only with contrast media, at the operator's
discretion. Whether both sides are used may be determined from
whether both sides are used in the subsequent protocol, and/or on
various default parameters. The injector may include default
setting screens for identifying the default use of injection heads
as well as methods for deriving volumes and/or flow rates from a
current protocol or prior test injections, allowing operator
configuration of the injector's behavior.
[0092] After the parameters of a test injection are set in the
manner noted above, in step 1220 the injector evaluates those
parameters in an optional step to determine whether there is
adequate volume for execution of both the test injection and the
subsequent protocol. If there is not adequate volume then in step
1222 the operator may be warned of the insufficiency, for example
by indicating in a red color or by blinking colors, or both, of the
part of the injection for which there will be insufficient volume
of fluid available. This warning is particularly useful in that it
avoids a circumstance where the operator must return to the imaging
room after a test injection or a partially completed injection, to
refill syringes and remove air, potentially wasting contrast media
and substantial time in re-work. In a circumstance of insufficient
volume, the injector may prevent the test injection, or may allow
operator override of the warning, as may be suitable for a given
clinical setting. The response of the injector may also be
different based upon whether there is inadequate contrast media
(which is more likely to have adverse effects on imaging) or
inadequate saline (which is less likely to have such effects).
[0093] After passing through the optional step 1220, the user may
enable the injector by pressing the enable key 1304 shown in FIG.
13 (if not previously enabled), which leads to step 1224 shown in
FIG. 12. At this point, the test injection may be initiated by the
operator pressing the start button in step 1224. When the start
button is pressed, then in step 1226 the test injection step(s) are
executed as set forth on the setup screen shown in FIG. 13.
Thereafter, the operator evaluates the test injection and, for
example, the quality of imaging achieved with the set flow rate
and/or the scan delay from the time of the injection to the
appearance of contrast media on the scanner, and in step 1228 may
adjust injection parameters for the injection protocol in response.
If there is a pressure limit hit during the test injection, then
the injector may disable, and provide a warning that a pressure
limit was hit, so that the operator is spurred to make
modifications through step 1228 before re-enabling the injection
prior to execution of the protocol. Thereafter, the user may
depress the start button in step 1230 to cause the injector to
execute the injection protocol in step 1232.
[0094] It will be appreciated that one use of the test injection
may be to identify the time required for contrast media to reach a
particular part of the patient's body where it can be effectively
imaged, so that, for example, the technician may set a scan delay
time defining when scanning should commence after an injection has
begun. To facilitate this activity by the technician, an injector
in accordance with principles of the present invention may
incorporate a number of features that work with the test injection
function to ensure an accurate scan delay calculation.
[0095] First, the injector may be usable to compute a scan delay
time from (a.) the reconstruction time of the scanner being used
and (b.) the observed time delay from the beginning of injection to
the appearance of contrast media on the scanner display. The
reconstruction time of the scanner must be subtracted from the
observed time delay to identify an accurate scan delay time, since
observation of contrast on the scanner will be after contrast has
actually arrived at the location seen on the screen, due to
reconstruction delay. Thus, to facilitate the determination of an
accurate scan delay, the injector may facilitate computation of the
difference of the observed time difference and scanner
reconstruction time. An injector configured to compute this
difference may also be configured to assist in measuring the time
delay between the start of injection and observation of contrast,
for example by measuring an elapsed time between the start of an
injection and a input by the technician that contrast is being
observed on the scanner display.
[0096] Second, the injector may assist in the repeatability of
injection activity by including functionality to return the state
of the Y or V tubing connected to the injector to a predetermined
state. For example, the desired initial state prior to an injection
may be that the tubing, through to the injection site, be filled
with saline. This initial state is a potentially important part of
the timing that will be achieved in an injection, as the initial
flow of contrast into the injection site may be delayed by several
seconds corresponding to the time to flush saline out of the tubing
and contrast into the tubing. Alternatively, the initial state
prior to an injection may be that the tubing is filled with
contrast, or some part of the tubing has saline and some part has
contrast. Those initial conditions will have different
corresponding behaviors in the timing of the start of an
injection.
[0097] An injection in accord with principles of the present
invention may contain a feature in which the main single line
section of the Y or V tubing is prefilled with contrast, saline, or
any predetermined combination of the two, according to the settings
of the injector and/or preferences of the operator. To implement
this feature the injector would contain information about the
specific tubing used, the volume of tubing after the joint to a
single tube, as well as the desired initial condition. If the main
single line section is no greater than 10 ml in capacity, then an
initial fill of that section by a desired fluid may be assured by a
push of 10 ml of the desired fluid as a final step prior to
initiation of the injection.
[0098] An injector implementing this initial condition function may
follow a test injection as set forth in FIG. 12 by such a single
push of saline or contrast, as desired, to return the injector to
the desired initial condition. Thus, for example, if a test
injection involves a final step that is a contrast injection, and
the desired initial condition is to have the single main line
flushed with saline, then after the test injection the injector
would automatically push saline to flush the single main line and
return the injector to the desired initial state. The obverse
activity could be performed where a test injection has a final step
that is a saline injection and the desired initial condition is to
fill the single main line with contrast.
[0099] It will be further appreciated that the desired initial
condition for an injection may be a parameter or may be deduced
from the nature of the protocol requested; e.g., in one embodiment
it might be assumed that if the first injection step is contrast
that the desired initial condition is to have the single main line
filled with saline fluid, and so proceed at the initialization of a
test injection as well as in the initialization of the injector
after the test injection and prior to execution of the programmed
protocol.
[0100] While the present invention has been illustrated by a
description of various embodiments and while these embodiments have
been described in considerable detail, it is not the intention of
the applicants to restrict or in any way limit the scope of the
appended claims to such detail. Additional advantages and
modifications will readily appear to those skilled in the art. The
invention in its broader aspects is therefore not limited to the
specific details, representative apparatus and method, and
illustrative example shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of applicant's general inventive concept.
* * * * *