WO2010051587A1

WO2010051587A1 - Dynamic control of medical device user interface

Info

Publication number: WO2010051587A1
Application number: PCT/AU2009/001441
Authority: WO
Inventors: Nicholas Betts
Original assignee: Signostics Ltd
Current assignee: Signostics Ltd
Priority date: 2008-11-07
Filing date: 2009-11-05
Publication date: 2010-05-14
Anticipated expiration: 2011-05-07

Abstract

A user interface for a hand held ultrasound scanner device including a control member intended for single handed use the control member producing at least one directional output in response to a first control movement and one selection output in response to a second control movement. The selection output, when activated during acquisition of an ultrasound scan, causes the activation of a dynamic control a user can use to set the value of an operational parameter which affects the acquisition of the ultrasound scan.

Description

DYNAMIC CONTROL OF MEDICAL DEVICE USER INTERFACE

TECHNICAL FIELD

The present invention relates to a hand held medical diagnostic ultrasound device with a user interface for scan parameter control, and a method of control implemented through such a user interface.

BACKGROUND ART

Ultrasound has been used for medical imaging for many years. An ultrasound transducer is excited to transmit ultrasound waves into the body of a patient. These waves are reflected by features within the body. The returning echoes are received by a transducer and the resulting signals are used to form an image of features within the body.

The progress of electronics and information technology has made the control of ultrasound imaging machines a significant problem. The received signal is digitised immediately at the transducer output. This enables a wide range of complex digital signal processing techniques to be applied, which would have been prohibitively difficult or expensive to apply in analogue componentry. The user or manufacturer controls these functions by computer program control. The number and range of these controls which may be accessible to a user are considerable. A quite rich and complex user interface is required to manage the range of options.

These machines also provide many convenient features beyond the mere receipt and display of ultrasound scan images. A full computer user interface is provided, enabling patient data to be added and associated with scans. Scans can be stored for later retrieval, or transmitted over computer networks. Text and graphic annotations can be added to scans.

At the same time as imaging machines have become more complex, it has become possible to make such machines much smaller. Ultrasound machines are now portable, no longer requiring a dedicated space, but being mounted on a cart which can be moved to a patient's bedside. The machines may even be made small enough to be hand carried. This has greatly extended the usefulness of ultrasound, especially bringing it into the emergency ward and to assist in such routine procedures as line insertion.

However, the machines must still provide a wide range of user and image manipulation functionality which requires a complex user interface. In order to implement the complex user interface, a multiplicity of knobs or other control members and a keyboard and computer style screen are provided. This style of physical user interface is a major contributor to the size and cost of ultrasound units. The need to provide these user interface elements represents an impediment to further miniaturisation of ultrasound imaging equipment and a barrier to increased use of ultrasound in point of care situations.

DISCLOSURE OF THE INVENTION

In one form of this invention there is proposed a hand held ultrasound scanner device with a user interface including a control member adapted for single handed use wherein said control member produces at least one directional output in response to a first control movement by a user and at least one selection output in response to a second control movement by a user wherein the selection output, when activated during acquisition of an ultrasound scan, causes the activation of a dynamic control, said dynamic control being operable by a user using said control member to set the value of an operational parameter for the acquisition or display of the ultrasound scan.

For a handheld device a user may have no free hand to operate any controls whilst continuing to support the unit and perform the scan. Alternatively, a user may need to use the hand not performing a scanning function to perform some other function, such as needle insertion.

In an embodiment, a user interface is provided to allow the control of the scan process without the need to manipulate controls with a free hand. That is, a hand which is being used to perform a scan or support the DPU may also be used to control at least one parameter of the scan acquisition process.

The dynamic control is an image displayed on a display, which may be the same display which is being used to display the ultrasound scan or another display. The dynamic control may include an element which is apparently fixed and an element which is apparently moveable. Manipulation of the control member produces the directional output which is received by interface software. The directional output has a direction, and a magnitude. The software increases or decreases the magnitude of the operational parameter according to the direction and magnitude of the directional output. The software also apparently causes the moveable element to move, indicating the degree to which the operational parameter is being changed. The display of the scan being acquired changes to reflect the change in the operational parameter.

In preference, the dynamic control image is a slider control with a visual indicator bar indicating the currently selected value of the operational parameter

Preferably, the control member is a thumbwheel or scrollwheel, adapted to be rotated in a forward and a reverse direction, which supplies the directional output, and to be pressed, providing the selection output.

In an embodiment, the directional output may also include an indication of how fast or how hard the user has manipulated the control member, which may be called an urgency indication. Where the control member is a scrollwheel, this would indicate how rapidly the user has rotated the scrollwheel. This information may be used to cause the operational parameter to be varied by a greater or lesser extent for the same magnitude of directional output, depending on this urgency indication.

In an embodiment, the display screen is a touch screen, and the control member is a portion of that screen, adapted to detect a user's digit being slid in at least one direction, and to detect a tap as the second user control movement. Alternatively, a separate touch sensitive element may be provided as the control member.

In a further embodiment, the directional output for the user interface software may be provided by two push buttons, with one button providing a directional signal indicating that an increased value of the parameter to be controlled is desired, the other that the value is to be decreased. The length of time for which a button is depressed indicates the amount by which the parameter is to be varied. A further button or other control may provide the selection output, or this may be provided by a chord where both directional buttons are depressed simultaneously.

In a preferred embodiment, the device does not have a keyboard and has at most four user manipulable control members. This allows for a significant reduction in size and weight compared to conventional ultrasound machines. In preference, the device weighs less than one kilogram.

In a more preferred embodiment, the device weighs less than 450 grams.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a view of a hand-held ultrasound scanning device including a preferred embodiment of the present invention.

Figure 2 is a graph of ultrasound echo intensity against depth.

Figure 3 is a view of an ultrasound application display screen of the interface of the invention.

Figure 4 is a representation of the response of a time gain compensator. Figure 5 is a view of an interface screen providing depth control. Figure 6 is a view of an interface screen providing near level control. Figure 7 is a view of an interface screen providing far level control. Figure 8 is a view of an interface screen providing gain delay control. Figure 9 is a view of an interface screen providing gain rate control.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to Fig 1 , there is illustrated a hand held ultrasound scanning device according to an embodiment of the invention. There is a hand held ultrasonic probe unit 10, a display and processing unit (DPU) 1 1 with a display screen 16 and a cable 12 connecting the probe unit to the DPU 11. The DPU includes a control member in the form of a thumbwheel 18, which is able to be rotated up and down and to be pressed inward to the body of the DPU. These movements provide control outputs for use by the user interface software. The rotation provides a directional output, indicating the direction in which the wheel is being rotated, and also how far the wheel has been rotated from the most recent rest position and optionally how quickly the wheel is being rotated. The pressing of the thumbwheel provides a selection output to the user interface software. There is also provided two further interface control members, being control buttons, a back button 17, and a start button 20 which also provide control outputs to the user interface software. The probe unit 10 includes an ultrasonic transducer 13 which transmits pulsed ultrasonic signals into a patient's body 14 and receives returned echoes from the target body 14.

In this embodiment, the transducer transmits and receives in only a single direction at a fixed orientation to the probe unit, producing data for a single scanline 15. An image of an area or volume within the target body is built up by sweeping the scanline over that area or volume.

The probe unit further includes an orientation sensor 19 capable of sensing orientation or relative orientation about one or more axes of the probe unit. Thus, in general, the sensor is able to sense rotation about any or all of the axes of the probe unit.

The sensor may be implemented in any convenient form. In an embodiment the sensor consists of three orthogonally mounted gyroscopes. In further embodiments the sensor may consist of two gyroscopes, which would provide information about rotation about only two axes, or a single gyroscope providing information about rotation about only a single axis.

The probe unit includes a transducer 13 which acts to transmit and receive ultrasonic signals. A diplexer is used to switch the transducer between transmit and receive circuitry.

The probe unit includes circuitry to provide a pulsed voltage to the transducer 13. The transducer produces an interrogatory ultrasonic pulse in response to each electrical pulse.

This interrogatory pulse travels into the body and is reflected from the features of the body to be imaged as an ultrasonic response signal. This response signal is received by the transducer and converted into an electrical received signal.

The depth from which the echo is received can be determined by the time delay between transmission and reception, with echoes from deeper features being received after a longer delay.

Ultrasound beams travelling through tissue become progressively weaker due to interactions with the tissue, which cause tissue friction. The term that is used to describe the reduction of signal strength with depth is attenuation. With ultrasound imaging, attenuation affects both the transmitted pulse and the returning echo. The relationship between the received echo intensity and tissue depth is therefore not linear, but exponential as shown in Figure 2.

Ultrasound systems must offer a means of countering the effects of attenuation, or there would be a progressive 'fade out' of the image as depth increases. The solution is to progressively increase the level of amplification applied to the returning signal, so that echoes from greater depth are compensated for the increased attenuation they have suffered.

This compensation is achieved by a Time Gain Compensation (TGC) circuit. The TGC applies variable amplification, conceptually as shown in Figure 4, which is a plot of applied amplification against time of travel of the ultrasound echo. Time of travel of the ultrasound echo is equivalent to depth of the tissue returning the echo.

The characteristics of the amplification are selected to compensate for the depth attenuation, giving a compensated receive signal where the intensity is proportional to the reflectiveness of the feature which caused the echo. In general, the amplification characteristics may take any shape.

In use, a user applies the probe unit 10 to a body to be imaged 14. In order to make an ultrasound scan, the user presses the Start button 20 to start a scan, or a toolbar icon (not shown in the illustrated embodiment) may also be used to start a scan. In a further embodiment, a control may be provided on the probe unit which will also perform this function.

The user then rotates the probe as required to sweep the ultrasound beam over the desired area, keeping linear displacement to a minimum, in embodiments where displacement is not sensed.

In embodiments where rotation about all axes is not sensed, the user will also keep rotation about unsensed axes, that is axes about which rotation is not detected by the sensor of the embodiment, to a minimum.

Ultrasound energy pulses are transmitted by the transducer into the body of the patient. This energy is reflected by features within the patient's body, and these achoes are received by the transducer. An electrical response signal is produced by the transducer in response to the received echoes. At the same time, data is received from the orientation sensor 19. This data is the rotation about the sensed axes of the probe unit. It may be the angular change in the position of the probe unit since the immediately previous transducer pulse, or the orientation of the probe unit in some defined frame of reference. One such frame of reference may be defined by nominating one transducer pulse, normally the first of a scan sequence, as the zero of orientation.

The sensor data and the response signal are passed to the DPU 1 1 where they are combined to give a scanline. A scanline is a dataset which comprises a sequential series of intensity values of the response signal combined with orientation information. A scan dataset is a plurality of sequentially received scanlines.

A scan data set is built up by a user rotating the probe unit about at least one sensed axis while keeping the positional displacement to a minimum. The pulsed voltage is continued to be supplied to the transducer and each pulse results in a scanline.

Each scanline is a series of values for the intensity of the echo returned from increasing depth into the subject body.

An application is run by the DPU 1 1 to process the scanlines for display. As shown in Figure 3, the scanlines are displayed as an ultrasound image 31 on the display area 32 of the ultrasound application screen.

General information relevant to the scan may also be displayed. In this case, the time 33 and the patient name 34 are displayed.

Prior art devices have control units which are supported on trolleys, or other supports, leaving the operator with a free hand. A complex interface with multiple knobs and buttons is generally provided for control of the scan in progress.

For a handheld device as used in an embodiment of the invention, when in use, the probe unit is held by the user in one hand and the DPU in the other. There is no free hand to operate any controls whilst continuing to support the DPU.

When a scan has been captured, and is being examined, the probe unit may be released by the hand holding it, and that hand may be used to manipulate a user interface provided by a touchscreen. However, there are a number of parameters which it is advantageous to control while a scan is in progress. Accordingly, a user interface is provided to allow the control of the scan process without the need to manipulate controls with a free hand. That is, a hand which is being used to perform a scan or support the DPU may also be used to control at least one parameter of the scan acquisition process.

In this embodiment, the ultrasound application displays a toolbar 35 at the bottom of the display screen. This toolbar includes icons associated with functions relevant to the ultrasound application which is active.

In order to make use of the functions provided by the ultrasound application, a user moves the thumbwheel 18. The user is able to move the thumbwheel with the same hand which is being used to hold the DPU. The thumbwheel provides a control signal output which indicates in which direction it has been moved, and one or both of how far or how fast it has been moved. This control signal is processed by the user interface software running on the DPU which highlights each of the icons in turn. When the required function icon is highlighted, the user presses the thumbwheel to select that function, which is then performed by the device.

In embodiments where the display is a touchscreen, the required function may alternatively be selected by touching the screen where the icon is displayed.

The ultrasound image 31 is a sector of a circle, where the radius of the circle 36, is the depth of scan of the ultrasound image. This equates to the full length of an acquired scanline. Where the operator is interested only in features near the surface of the sector being scanned, it is advantageous to reduce the length of the received scanline or to reduce the length of the displayed scanline, and to adjust the display such that the shortened scanline continues to occupy the whole of the display screen.

It is further advantageous to be able to make adjustment of the depth while the scan is in progress, that is, while the user continues to rotate the probe unit against the subject being scanned. Other parameters may also advantageously be adjusted dynamically while a scan is being acquired.

Referring now to Figure 4, there is shown an idealised plotline 41 of the amplification provided by the time gain compensation circuit. This plotline is defined by four parameters. These are the gain delay time 42, the near field gain level 43, the far field gain level 45 and the gain rate 44 which is the slope of the plotline.

The interface of the invention provides for these parameters to be manipulated by the user while scanning is in progress, using the hand which is holding the DPU.

Whilst scanning, a user may wish to adjust the depth of the scan. In an embodiment, the user depresses the thumbwheel 18, which causes the display of Figure 5 to appear on the display unit. The display includes a slider control 51 , with a visual indicator bar 52. There is a label 53 indicating the parameter which is to be controlled. There is also a numerical display 54 of the current value of that parameter. In this figure the control indicates that the depth of scan is 13 cm, being somewhat greater than half the maximum possible depth.

In order to vary the depth parameter, the user rotates the thumbwheel. Rotation of the thumbwheel produces a directional output which is passed to the user interface software. An output indicating rotation in one direction will increase the displayed scan depth, an output indicating rotation in the other will reduce the displayed scan depth. The amount, and optionally the speed, by which the thumbwheel is rotated determines the amount by which the depth parameter is adjusted. The visual indicator bar moves up and down the slider control and the numerical display changes to indicate the changing value of the parameter. The slider control allows for rapid visual approximation of the depth, while the numerical display gives an accurate, but less intuitive indication of the parameter value.

When the thumbwheel is moved to adjust the depth parameter, the DPU resizes the image being displayed to show the image to the selected depth using the full available image area. This allows shallower features to be shown at an increased resolution. In one embodiment, changing the depth parameter changes only the display of the image. In other embodiments, the DPU may send a signal to the probe unit to reduce the length of the scanlines being obtained. This may allow the probe unit to reduce the power output if a shallower scan is required.

As these scanlines are displayed, the displayed scan sector 55 progressively shows a sector scan to the selected depth. In embodiments with a touchscreen the slider control is touch sensitive, enabling the slider control to be moved with a user's thumb or finger moving against the screen.

Whilst scanning, a user may wish to adjust parameters other than depth of scan. A subset of functions which a user might wish to adjust while scanning is provided by the interface. Depressing the thumbwheel multiple times provides multiple selection outputs to the user interface software which causes the displayed dynamic control to cycle through these possibilities.

In the illustrated embodiment, the near field gain is adjustable. Referring to Figure 4, the near field gain 43 is the degree of amplification provided to the ultrasound echoes returning from the shallowest part of the ultrasound target. In order to adjust the near field gain, a user presses the thumbwheel twice. The depth display of Figure 5 appears briefly, to be replaced by the near level adjustment display of Figure 6.

The display includes a slider control 61 , with a visual indicator bar 62. There is a label 63 indicating that the parameter which is to be controlled is "Near Level" which is the near field gain. There is also a numerical display 64 of the current value of that parameter. In this figure the control indicates that the near field gain is 7OdB, nearly the maximum possible value for the parameter.

Where the top part 65 of a scan image is bright as in Figure 6, a user may wish to reduce the near field gain, where it is dark, a user may wish to increase this value. In order to vary the near field gain, the user rotates the thumbwheel. The slider control and the numerical display indicate the changing value of the parameter. The slider control allows for rapid visual approximation of the applied gain, while the numerical display gives an accurate, but less intuitive indication of the parameter value. When the thumbwheel is moved to adjust the near field gain parameter, the DPU provides a signal to the TGC to change the near field gain to the newly selected value. This change is then reflected in the received and displayed scanlines.

A further adjustable parameter is the far field gain. Referring to Figure 4, the near field gain 45 is the degree of amplification provided to the ultrasound echoes returning from the deepest part of the ultrasound target. In order to adjust the far field gain, a user presses the thumbwheel three times. The far field gain adjustment screen of Figure 7 appears on the third press.

The display includes a slider control 71 , with a visual indicator bar 72. There is a label 73 indicating that the parameter which is to be controlled is "Far Level" which is the far field gain. There is also a numerical display 74 of the current value of that parameter. In this figure the control indicates that the near field gain is 5OdB, a little more than half the maximum possible value for the parameter.

Where the bottom part 75 of a scan image is dark as in Figure 7, a user may wish to increase the far field gain, where it is too bright, a user may wish to increase this value. In order to vary the far field gain, the user rotates the thumbwheel. The slider control and the numerical display indicate the changing value of the parameter. When the thumbwheel is moved to adjust the near field gain parameter, the DPU provides a signal to the TGC to change the far field gain to the newly selected value. This change is then reflected in the received and displayed scanlines.

In the illustrated embodiment, the gain delay is adjustable. The Gain Delay parameter sets a depth delay before amplification begins, which is useful when there is a superficial area of no diagnostic interest, such as a large subcutaneous fat layer in an obese patient. This can be seen on Figure 4, where it can be seen that the gain delay 42 corresponds to a time period, and hence a tissue depth, during which the amplification provided by the TGC is constant.

In order to adjust this value, to account for a need to view or ignore the shallowest part of the ultrasound scan, the user presses the thumbwheel four times. The display of Figure 8 is displayed.

The display includes a slider control 81 , with a visual indicator bar 82. There is a label 83 indicating that the parameter which is to be controlled is the gain delay. There is also a numerical display 84 of the current value of that parameter. In this figure the control indicates that the gain delay is a depth of 5 cm.

The final parameter available for in-scan adjustment in the preferred embodiment is the gain rate. Referring to Figure 4 the gain rate 44 is the slope of the TGC amplification plotline. This is the rate at which the TGC increases gain with depth to compensate for the attenuation of the tissue through which the ultrasound signals are travelling. It is measured in dB/cm. Pressing the thumbwheel five times will bring up the display of Figure 9. The display includes a slider control 91 , with a visual indicator bar 92. There is a label

93 indicating that the gain rate is being adjusted. There is also a numerical display

94 of the current value of that parameter. In this figure the control indicates that the gain rate is 80 dB/cm, which is a little more than half the maximum possible value for the parameter.

A user may adjust the gain rate if it is known that the tissue which is being imaged is of a type where the attenuation varies from the average tissue attenuation by a significant amount.

Other parameters may be made available for in-scan adjustment in other embodiments.

Any other control accessible to and able to be manipulated by a user while holding the DPU with the same hand may be used. For example, one of the push buttons, 20,17 may be pressed to display the slider control. Each of the available controls, in this embodiment the push buttons 20,17 and the depressing of the thumbwheel 18, may bring up slider controls with different functions.

The dynamic control need not be a slider as in the described embodiments. Any display which indicates the approximate value of a controlled parameter between two extremes may be used. These may include, without limitation, colour filling sectors of a circle, clock face style meter displays and displays having varying colours, intensity or brightness.

A purely numerical control may be used, wherein the numerical value of the parameter, or an indicative scalar number such as a percentage, is displayed and varied to indicate the setting and variation of the value of the controlled parameter. Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognised that departures can be made within the scope of the invention, which is not to be limited to the details described herein but is to be accorded the full scope of the appended claims so as to embrace any and all equivalent devices and apparatus.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS

1. A hand held ultrasound scanner device having a user interface including a control member adapted for single handed use wherein said control member produces at least one directional output in response to a first control movement by a user and at least one selection output in response to a second control movement by a user wherein the selection output, when activated during acquisition of an ultrasound scan, causes the activation of a dynamic control, said dynamic control being operable by a user using said control member to set the value of an operational parameter for the acquisition or display of the ultrasound scan.

2. The hand held ultrasound scanner device of claim 1 wherein the dynamic control is operated by the second control movement.

3. The hand held ultrasound scanner device of claim 1 wherein the dynamic control is a slider control displayed on a display unit.

4. The hand held ultrasound scanner device of claim 1 wherein the dynamic control includes a numerical representation of the value of the operational parameter.

5. The hand held ultrasound scanner device of claim 1 wherein the device consists of one or more enclosures which are gripped by a user whilst an ultrasound scan is being acquired, wherein the control member is controlled by a user using a hand which is also being used to grip or support said enclosure.

6. The hand held ultrasound scanner device of claim 1 wherein the control member is a thumbwheel protruding from a casing, the first control movement being the rotating of the thumbwheel about an axis, the second control movement being depressing the thumbwheel toward the casing.

7. The hand held ultrasound scanner device of claim 1 wherein the operational parameter is one or more parameters selected from scan depth, near field gain, far field gain, gain delay and gain rate.

8. The hand held ultrasound scanner device of claim 1 wherein repeated operation of the selection output causes dynamic controls controlling further operational parameters to be activated.

9. The hand held ultrasound scanner device of claim 1 wherein the control member is a touch sensitive strip.

10. The hand held ultrasound scanner device of claim 9 wherein the first user control movement is to slide a digit along said strip, and the second user control movement is to tap said strip.

11.The hand held ultrasound scanner device of claim 9 wherein the touch sensitive strip is part of a touch sensitive display screen.

12. The hand held ultrasound scanner device of claim 1 wherein the control member consists of a thumbwheel providing the directional output and a push button providing the selection output.

13. The hand held ultrasound device of claim 1 wherein the device has a total weight of less than one kilogram.

14. The hand held ultrasound device of claim 1 wherein the device has a total weight of less than 450 grams.

15. A method of control of a hand held medical diagnostic ultrasound device wherein at least one operational parameter for the acquisition of an ultrasound scan is controlled by a user using a hand which is also being used to grip or support an enclosure forming part of the device.

16. The method of claim 15 wherein the enclosure encloses a display and processing unit.

17. The method of claim 15 wherein the enclosure encloses a probe unit.

18. The method of claim 15 wherein the operational parameter is controlled by manipulation of one or more control members having a selection output and a directional output.

19. A method of control of a hand held medical diagnostic ultrasound device of a type having a probe unit and a display and processing unit both of which are held by a user during use to acquire an ultrasound scan, wherein a dynamic control is provided on the display and processing unit which a user manipulates to set the value of an operational parameter while a scan is being acquired.

20. A hand held ultrasound scanner device for a hand held medical diagnostic ultrasound device substantially as described in the specification with reference to and as illustrated by any one or more of the accompanying drawings.

21.A method of control of a hand held medical diagnostic ultrasound device substantially as described in the specification with reference to and as illustrated by any one or more of the accompanying drawings.