Patent Description:
Pelvic floor dysfunctions (PFDs) are major conditions that frequently occur in adult women, carrying a significant burden on the quality of life. The incidence of PDFs tends to increase with age of the population. PFDs can manifest with symptoms such as incontinence, constipation, and/or prolapsed pelvic organs. Pelvic floor weakness is frequently generalized and clinically underdiagnosed, and medical imaging evaluation is of major importance especially prior to surgical correction. Medical imaging, such as Pelvic floor Ultrasound (US) or trans-perineal US, is a widely accepted tool for diagnosing PDFs in clinical practice. Papers on the topic include the paper by <NPL>. ; and <NPL>.

The Valsalva manoeuvre (VM) is often used during US examinations to assess the state of a subject's (e.g. patient's) pelvic floor muscles. During a VM, a clinician asks the subject to push out her pelvic floor muscles as hard as she can (for example, for <NUM> to <NUM> seconds), as if the subject is bearing down to pass a stool or deliver a baby. When the clinician says to start the VM, the subject will need to start pushing as hard as she can and keep pushing as much as possible for the duration of the VM. When the clinician says to relax, the subject can stop pushing. It is important that the subject achieves her maximum "push" during the VM in order for effective examination. The Valsalva manoeuvre is described in more detail in the paper by <NPL>.

In one type of examination, the mobility of the pelvic organs during a Valsalva manoeuvre and shape and size of the Levator Hiatus (LH) are measured during routine examination and used to diagnose PFDs. The dimension of the LH at the maximal point of a VM (e.g. the point at which the pressure applied by the subject is maximal) is an important diagnostic index in pelvic floor ultrasound since it is widely used as a standardized parameter. For example: an area of the LH over <NUM><NUM> is considered abnormal for western women, whilst an area greater than <NUM><NUM> is considered abnormal for Chinese women. Experienced ultrasound practitioners can achieve near <NUM>% reliability at diagnosing PFDs by measuring the area of the LH during the maximal point of the VM (see paper by <NPL>).

<CIT> disclosed a method of classifying pelvic floor states, which can automatically identify the pelvic floor states in the ultrasonic pelvic floor images, and automatically mark the pelvic floor states on the images. <CIT> disclosed a method for biomechanical mapping of the female pelvic floor with a vaginal tactile imaging probe equipped with a plurality of tactile sensors distributed along an external surface thereof.

According to the study by Rong et al. , cited above, some causes of inaccuracy in pelvic floor Ultrasound Examinations arise due to false negatives due to subjects not achieving their maximal Valsalva (e.g. not exerting their maximum possible pressure on the pelvic floor during the VM). In such cases the subject will not push the pelvic muscle out to its maximum extent and thus the maximal area of the LH will be underestimated. False negatives of this type can occur for a variety of reasons, for example, women may be reluctant to push to their maximum extent in a hospital setting, for example, due to the risk of urinary leakage.

Furthermore, some false negatives may arise due to the field of view (FOV) obtained during the imaging process not covering the pelvic floor muscles sufficiently to be able to reconstruct LH image. For example, if the FOV of the ultrasound probe is small or the probe is located in an unsuitable position, then the region of interest (ROI) for a 4D VM sequence will be reduced during dynamic VM and this can also lead to underestimation of the area of the LH (due to reconstructed C-plane from the selected one 3D volume image at maximal VM). These issues and others are addressed by embodiments herein.

Thus, according to a first aspect, there is provided an ultrasound system for use in monitoring a Valsalva Manoeuvre, VM performed by a subject. The ultrasound system comprises a computing apparatus configured to: receive a measurement of abdominal pressure, P, for the subject whilst the subject is performing the VM, wherein the measurement of abdominal pressure was measured using a sensor external to the body for measuring abdominal pressure; and determine an indication of whether the subject has effectively performed the VM by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the VM to a reference abdominal pressure, PRef, measured for the subject.

According to a second aspect there is an apparatus for use in monitoring a Valsalva Manoeuvre, VM performed by a subject, the apparatus comprising: a sensor external to the body for measuring abdominal pressure; and a computing apparatus, wherein the computing apparatus is configured to: obtain a measurement of abdominal pressure, P, for the subject, from the sensor, whilst the subject is performing a VM; and send the obtained measurement of abdominal pressure, P, for the subject to an ultrasound system for use by the ultrasound system as a reference abdominal pressure, PRef, in determining whether the subject has effectively performed the VM. The apparatus of the second aspect may be a consumer apparatus accompanied by a computer application for use by the subject at home.

According to a third aspect there is a method performed by an ultrasound system for use in monitoring a Valsalva Manoeuvre, VM performed by a subject. The method comprises: receiving a measurement of abdominal pressure, P, for the subject whilst the subject is performing the VM, wherein the abdominal pressure was measured using a sensor external to the body for measuring abdominal pressure; and determining an indication of whether the subject has effectively performed the VM by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the VM to a reference abdominal pressure, PRef, measured for the subject.

According to a fourth aspect there is a computer program product comprising a computer readable medium, the computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform the method of the third aspect.

Thus according to embodiments herein, there is an apparatus, such as a consumer apparatus, for measuring a reference pressure exerted by a subject during a VM, and a complementary apparatus for receiving the reference pressure and using it to determine an indication of whether the subject has effectively performed the VM. For example, the reference pressure may be determined, using the apparatus of the second aspect, whilst the subject is at home, in familiar surroundings where they may practice their VMs. The pressure achieved during such practice may then be used in an Ultrasound examination to determine whether the maximum pressure achieved during the VM performed in the hospital setting is representative of the maximum VM pressure that the subject can achieve in the home setting, thus ensuring that the VM is effectively performed. Ensuring that the VM is correctly performed reduces false negative PDF diagnoses.

Example embodiments will now be described, by way of example only, with reference to the following drawings, in which:.

As described briefly above, embodiments herein relate to systems, apparatus and methods therefor for monitoring a subject (e.g. patient) as the subject performs a Valsalva Manoeuvre (VM). The monitoring may be performed to determine whether the VM was performed correctly and/or to determine whether ultrasound (US) imaging data of the pelvic floor of the subject, obtained whilst the subject performed the VM, is likely to be suitable for assessing whether the subject has pelvic floor dysfunction (PDF).

The maximum extent of the LH during a Valsalva Manoeuvre is a standardised measurement used to diagnose whether the subject has PFD. As described above, one of the reasons that such examinations can lead to false negatives (e.g. where PFD is missed by the clinician) is if the subject does not push their pelvic floor muscles out to their maximum extent during the VM. If a maximum push is not achieved, then the maximum extent of the LH is not achieved either (e.g. the maximum extent of the LH that the subject should or can reach) and this leads to underestimation of the LH area (which is reference standard for diagnosing PFD).

Embodiments herein propose a "training system" whereby the subject is given an apparatus with which to monitor themselves as they perform VMs e.g. at home. The training system records the abdominal pressure measurements in the home as reference pressures for the subject. The reference pressures obtained in the home setting may be used as a bench mark in the hospital setting to determine whether the subject is pushing to their maximum extent possible during a hospital-monitored VM. If the subject does not achieve the reference pressure (or a pressure close enough to the reference pressure) in the hospital setting then they may be asked to repeat the VM, for example.

An example apparatus is illustrated in <FIG> which shows an apparatus for use in monitoring a Valsalva Manoeuvre, VM performed by a subject. In <FIG> the apparatus is a belt <NUM> comprising one or more external pressure sensors 102a, 102b. The belt is worn around the abdomen of the subject and holds the pressure sensor(s) against the subject's body. The apparatus <NUM> further comprises a computing apparatus <NUM> configured to obtain a measurement of abdominal pressure, P, for the subject, from the sensor, whilst the subject is performing a VM. The belt may be used to monitor a plurality of (practice) VMs performed by the subject, e.g. in order to determine the maximum pressure that the subject can achieve in their own home/under relaxed conditions. The historical or practice VMs may be performed at the same location (e.g. in the home) for comparison purposes between different pressure measurements, but performed by the same subject. The computing apparatus <NUM> is then configured to send an obtained measurement of abdominal pressure, P, for the subject to an ultrasound system for use by the ultrasound system as a reference abdominal pressure (e.g. a pressure that the subject is known to be able to achieve), PRef, for use in determining whether the subject has effectively performed a VM.

When the subject subsequently goes for an US pelvic floor examination, e.g. in a hospital setting, an US system such as that illustrated in <FIG> may be used. In the hospital setting, a belt similar to that described with respect to <FIG>, may be used to measure the abdominal pressure of the subject whilst the subject performs the VM. The belt will measure the abdominal pressure, and a computing apparatus in the ultrasound system <NUM> is configured to receive the measurement of abdominal pressure, P, and determine an indication of whether the subject has effectively performed the VM by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the VM to the reference abdominal pressure, PRef, measured for the subject (e.g. as obtained using the consumer apparatus <NUM> in the home setting). In this way, an indication can be given to the clinician of whether the subject has correctly performed the VM.

In this way, the apparatus in <FIG> can be used to monitor the subject as they perform a VM at home, before examination. The ultrasound system <NUM>, <NUM> in <FIG> can then be used to providing guidance tool to an ultrasound practitioner to help identify if a VM performed during an ultrasound examination is properly performed for a specific task before the subject leaves the examination room.

In more detail, and turning now to <FIG>, some embodiments herein are performed using a computing apparatus such as the computing apparatus <NUM>. Generally, the computing apparatus <NUM> may form part of a computer or system e.g. such as a mobile phone, tablet, laptop, desktop computer or other computing device. In some embodiments, the apparatus <NUM> may form part of a distributed computing arrangement or the cloud.

The computing apparatus comprises a memory <NUM> comprising instruction data representing a set of instructions and a processor <NUM> (e.g. processing circuitry or logic) configured to communicate with the memory and to execute the set of instructions. Generally, the set of instructions, when executed by the processor, may cause the processor to perform any of the embodiments of the method <NUM> or the method <NUM> as described below.

The processor <NUM> can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the computing apparatus <NUM> in the manner described herein. In particular implementations, the processor <NUM> can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein. The processor <NUM> can comprise one or more processors, processing units, multi-core processors and/or modules that are configured or programmed to control the computing apparatus <NUM> in the manner described herein. In some implementations, for example, the processor <NUM> may comprise a plurality of (for example, interoperated) processors, processing units, multi-core processors and/or modules configured for distributed processing. It will be appreciated by a person skilled in the art that such processors, processing units, multi-core processors and/or modules may be located in different locations and may perform different steps and/or different parts of a single step of the methods described herein.

The memory <NUM> is configured to store program code that can be executed by the processor <NUM> to perform the method described herein. Alternatively or in addition, one or more memories <NUM> may be external to (i.e. separate to or remote from) the computing apparatus <NUM>. For example, one or more memories <NUM> may be part of another device. Memory <NUM> can be used to store any information or data received, calculated or determined by the processor <NUM> of the computing apparatus <NUM> or from any interfaces, memories or devices that are external to the computing apparatus <NUM>. The processor <NUM> may be configured to control the memory <NUM> to store such information.

In some embodiments, the memory <NUM> may comprise a plurality of sub-memories, each sub-memory being capable of storing a piece of instruction data. For example, at least one sub-memory may store instruction data representing at least one instruction of the set of instructions, while at least one other sub-memory may store instruction data representing at least one other instruction of the set of instructions.

It will be appreciated that <FIG> only shows the components required to illustrate this aspect of the disclosure and, in a practical implementation, a computing apparatus <NUM> may comprise additional components to those shown. For example, a computing apparatus <NUM> may further comprise a display. A display may comprise, for example, a computer screen, and/or a screen on a mobile phone or tablet. A computing apparatus may further comprise a user input device, such as a keyboard, mouse or other input device that enables a user to interact with the computing apparatus, for example, to provide initial input parameters to be used in the method described herein. A computing apparatus <NUM> may comprise a battery or other power supply for powering the computing apparatus <NUM> or means for connecting the computing apparatus <NUM> to a mains power supply.

In some embodiments, a computing apparatus <NUM> may be comprised in (e.g. form part of) an ultrasound system. For example, an ultrasound system may comprise the computing apparatus <NUM> described above, and further comprise a transducer with which to record the sequence of ultrasound image data.

In some embodiments herein, a computing apparatus <NUM> is comprised in (e.g. forms part of) a consumer apparatus <NUM> as illustrated in <FIG>.

Turning now to other embodiments, some embodiments herein relate to ultrasound systems. <FIG> shows an example ultrasound system <NUM>. The ultrasound system <NUM> may comprise a computer apparatus <NUM> as described above. In other embodiments, components of the ultrasound system <NUM> may be adapted to perform the method <NUM> as described below.

The system <NUM> comprises an array transducer probe <NUM> which has a transducer array <NUM> for transmitting ultrasound waves and receiving echo information. The transducer array <NUM> may comprise CMUT transducers; piezoelectric transducers, formed of materials such as PZT or PVDF; or any other suitable transducer technology. In this example, the transducer array <NUM> is a two-dimensional array of transducers <NUM> capable of scanning either a 2D plane or a three dimensional volume of a region of interest. In another example, the transducer array may be a 1D array.

The transducer array <NUM> may be coupled to a microbeamformer <NUM> which controls reception of signals by the transducer elements. Microbeamformers are capable of at least partial beamforming of the signals received by sub-arrays, generally referred to as "groups" or "patches", of transducers as described in <CIT>), <CIT>), and <CIT>).

In an alternative embodiment, instead of a microbeamformer <NUM>, the transducer array may be operated directly by a main system beamformer (not shown in <FIG>).

The system <NUM> may further comprise a transmit/receive (T/R) switch <NUM>, which the microbeamformer <NUM> can be coupled to and which switches the array between transmission and reception modes. The transmission of ultrasound beams from the transducer array <NUM> is directed by a transducer controller <NUM> coupled to the microbeamformer by the T/R switch <NUM> and a main transmission beamformer (not shown), which can receive input from the user's operation of the user interface or control panel <NUM>. The controller <NUM> can include transmission circuitry arranged to drive the transducer elements of the array <NUM> (either directly or via a microbeamformer) during the transmission mode.

It is noted that in an alternative embodiment, where instead of a microbeamformer <NUM>, the transducer array is operated directly by a main system beamformer, a T/R switch <NUM> may protect the main beamformer <NUM> from high energy transmit signals.

In a typical line-by-line imaging sequence, the beamforming system within the probe may operate as follows. During transmission, the beamformer (which may be the microbeamformer or the main system beamformer depending upon the implementation) activates the transducer array, or a sub-aperture of the transducer array. The sub-aperture may be a one-dimensional line of transducers or a two dimensional patch of transducers within the larger array. In transmit mode, the focusing and steering of the ultrasound beam generated by the array, or a sub-aperture of the array, are controlled as described below.

For each line (or sub-aperture), the total received signal, used to form an associated line of the final ultrasound image, will be a sum of the voltage signals measured by the transducer elements of the given sub-aperture during the receive period. The resulting line signals, following the beamforming process below, are typically referred to as radio frequency (RF) data. Each line signal (RF data set) generated by the various sub-apertures then undergoes additional processing to generate the lines of the final ultrasound image. The change in amplitude of the line signal with time will contribute to the change in brightness of the ultrasound image with depth, wherein a high amplitude peak will correspond to a bright pixel (or collection of pixels) in the final image. A peak appearing near the beginning of the line signal will represent an echo from a shallow structure, whereas peaks appearing progressively later in the line signal represent echoes from structures at increasing depths within the subject.

In addition, upon receiving the echo signals from within the subject, it is possible to perform the inverse of the above described process in order to perform receive focusing. In other words, the incoming signals may be received by the transducer elements and subject to an electronic time delay before being passed into the system for signal processing. The simplest example of this is referred to as delay-and-sum beamforming. It is possible to dynamically adjust the receive focusing of the transducer array as a function of time.

The structural and motion signals produced by the B mode and Doppler processors are coupled to a scan converter <NUM> and a multi-planar reformatter <NUM>. The scan converter <NUM> arranges the echo signals in the spatial relationship from which they were received in a desired image format. In other words, the scan converter acts to convert the RF data from a cylindrical coordinate system to a Cartesian coordinate system appropriate for displaying an ultrasound image on an image display <NUM>. In the case of B mode imaging, the brightness of pixel at a given coordinate is proportional to the amplitude of the RF signal received from that location. For instance, the scan converter may arrange the echo signal into a two dimensional (2D) sector-shaped format, or a pyramidal three dimensional (3D) image. The scan converter can overlay a B mode structural image with colors corresponding to motion at points in the image field, where the Doppler-estimated velocities to produce a given color. The combined B mode structural image and color Doppler image is able to depict tissue motion and blood flow within the structural image field. The multi-planar reformatter will convert echoes that are received from points in a common plane in a volumetric region of the body into an ultrasound image of that plane, as described in <CIT>). A volume renderer <NUM> converts the echo signals of a 3D data set into a projected 3D image as viewed from a given reference point as described in <CIT>).

The 2D or 3D images are coupled from the scan converter <NUM>, multi-planar reformatter <NUM>, and volume renderer <NUM> to an image processor <NUM> for further enhancement, buffering and temporary storage for display on an image display <NUM>. The imaging processor may be adapted to remove certain imaging artifacts from the final ultrasound image, such as for example,: acoustic shadowing, for example caused by a strong attenuator or refraction; posterior enhancement, for example caused by a weak attenuator; reverberation artifacts, for example where highly reflective tissue interfaces are located in close proximity; and so on. In addition, the image processor may be adapted to handle certain speckle reduction functions, in order to improve the contrast of the final ultrasound image.

In addition to being used for imaging, the blood flow values produced by the Doppler processor <NUM> and tissue structure information produced by the B mode processor <NUM> are coupled to a quantification processor <NUM>. The quantification processor may be used for making measurements in the images. The quantification processor may receive input from a user control panel <NUM>, such as the seed points for locating the surface of the muscle, as described in detail below.

Output data from the quantification processor is coupled to a graphics processor <NUM> for the reproduction of measurement graphics and values with the image on the display <NUM>, and for audio output from the display device <NUM>. The graphics processor <NUM> can also generate graphic overlays for display with the ultrasound images. These graphic overlays can contain standard identifying information such as patient name, date and time of the image, imaging parameters, and the like. For these purposes the graphics processor receives input from the user interface <NUM>, such as patient name. The user interface is also coupled to the transmit controller <NUM> to control the generation of ultrasound signals from the transducer array <NUM> and hence the images produced by the transducer array and the ultrasound system. The transmit control function of the controller <NUM> is only one of the functions performed. The controller <NUM> also takes account of the mode of operation (given by the user) and the corresponding required transmitter configuration and band-pass configuration in the receiver analog to digital converter. The controller <NUM> can be a state machine with fixed states.

The skilled person will appreciate that the detail provided above and the components illustrated in <FIG> are an example only and that an ultrasound system may have different components to those illustrated therein.

Turning to <FIG>, there is a computer implemented method <NUM> performed by an ultrasound system for use in monitoring a Valsalva Manoeuvre, VM performed by a subject. Embodiments of the method <NUM> may be performed, for example by an ultrasound system such as the ultrasound systems <NUM>, <NUM> or <NUM> described above. In some embodiments the method <NUM> may be performed by a computing apparatus <NUM> described above.

Briefly, in a first step <NUM>, the method <NUM> comprises receiving a measurement of abdominal pressure, P, for the subject whilst the subject is performing the VM, wherein the measurement of abdominal pressure was measured using a sensor external to the body for measuring abdominal pressure. In a second step <NUM>, the method <NUM> comprises determining an indication of whether the subject has effectively performed the VM by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the VM to a reference abdominal pressure, PRef, measured for the subject.

In more detail, the measurement of abdominal pressure received in step <NUM> is measured using a sensor external to the body for measuring abdominal pressure. In some embodiments, the sensor is comprised in a belt that is worn around the subject's abdomen, as illustrated in <FIG> and <FIG> above. In some embodiments, the sensor measures the pressure in a direction perpendicular to the abdominal muscles during the VM (e.g. outward pressure on the belt).

In other embodiments, the sensor may be embedded in a patch that is attached or stuck to the subject, or measured using a handheld sensor. The skilled person will appreciate that these are merely examples and that any external sensors suitable for measuring abdominal pressure may be used.

In step <NUM> the method <NUM> then comprises determining an indication of whether the subject has effectively (e.g. correctly; exerting a pressure close to the maximum possible pressure achievable for the subject) performed the VM by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the VM to a reference abdominal pressure, PRef, measured for the subject.

Generally, the reference pressure is a previous pressure achieved by the subject, or a target pressure for the subject. The reference pressure may be based on a pressure that the subject has previously achieved whilst performing a VM.

The reference pressure may be a maximum historical abdominal pressure measurement measured for the subject, determined from a plurality of historical abdominal pressure measurements, each of the plurality of historical abdominal pressure measurements having been taken as the subject performed a VM.

As an example, the plurality of historical abdominal pressure measurements may have been made using a consumer apparatus as described above with respect to <FIG>. The plurality of historical abdominal pressure measurements may have been made whilst the subject was at home, or in some other environment where the subject is able to be comfortable. The reference pressure may be the maximum pressure previously obtained by the subject during a VM, for example, the maximum value of the plurality of historical abdominal pressure measurements.

In step <NUM>, the measurement of abdominal pressure for the subject may be compared to the reference pressure by taking a ratio of P/PRef. In other words, the indication of whether the subject has effectively performed the VM may be based on a measure of P/Pref.

For example, the indication may be a value of P/PRef. In other examples, the indication may indicate whether P/PRef is greater a first predefined threshold. The first predefined threshold may be, for example, about <NUM>. For example, the indication may indicate if the subject achieves a pressure <NUM>% or more of the maximum recorded historical pressure for the subject. As another example, if the subject achieves a pressure <NUM>% or more of the maximum recorded historical pressure for the subject, then the indication may indicate that the VM was performed correctly.

In some embodiments, the method may comprise sending a signal to a display to cause the display to provide an indication of whether P/PRef is greater than the first predefined threshold. As such, the indication may be displayed on the display for use by a clinician in determining whether the subject has correctly (or sufficiently) performed a VM. From this, the clinician can use the indication to determine whether US images obtained during the VM were taken at an abdominal pressure close enough to the subject's maximal pressure, and thus whether the US images are suitable for diagnostic purposes e.g. suitable for use in diagnosing whether the subject has PFD.

In some embodiments, the method may further comprise obtaining ultrasound data of the pelvic floor of the subject whilst the subject is performing the VM. The ultrasound image data may be obtained as part of a pelvic floor examination. The ultrasound images may for example, be Pelvic floor US images, trans-perineal US images or translabial ultrasound images.

The ultrasound data may comprise raw data or radiofrequency (RF) signal data. The US data may alternatively or additionally be formatted into image data in a format such as e.g. the Digital Imaging and Communications in Medicine (DICOM) image format or any other suitable image format. The US data may be three-dimensional or two dimensional. Generally a sequence of images may be obtained. For example, at <NUM> second intervals throughout performance of the VM.

<FIG> illustrates an introital static 3D volume processed to demonstrate the relationship of the three orthogonal planes-coronal <NUM>, sagittal <NUM>, and axial <NUM> in the context of a pelvic floor ultrasound examination. The cursor dot seen in each plane represents the exact same spot in each plane.

Generally, the method <NUM> may comprise making measurements of the area of the levator hiatus, LH which is illustrated in <FIG> shows a mid sagittal 2D image at A-plane from a four-dimensional US acquisition for organ descent and hiatal ballooning or over-distensibility (<NUM> degrees acquisition angle). The region of interest (box in A in Fig. <NUM>) is set between the symphysis pubis (S) on the left and levator ani (LA) on the right. A indicates anal canal; B bladder; R, rectal ampulla; U, urethra; and V, vagina. The dotted contour <NUM> in the right-hand image <NUM> is the circumference or perimeter of the Levator hiatus (LH) in the plane of minimal dimensions; the solid white line in both <NUM> and <NUM> is the hiatal anteroposterior (AP) diameter in the midsagittal (anteroposterior) plane.

Generally, the midsagittal plane is determined from the 3D volume frame in <FIG> as shown in <FIG>, and C-plane reconstruction/rending for the LH image is implemented by selection of key points and drawing a line through the key points as minimal dimension plane.

The area of the LH may be determined, for example, by segmenting the US image data to determine the boundaries of the LH and determining the area therein. The skilled person will be familiar with segmentation and methods for performing segmentation of an image, but briefly, image segmentation involves extracting shape/form information about the objects or shapes captured in an image. This may be achieved by converting the image into constituent blocks or "segments", the pixels or voxels in each segment having a common attribute.

One method of image segmentation is Model-Based Segmentation (MBS), whereby a triangulated mesh of a target structure (such as, a mesh of the LH) is adapted in an iterative fashion to features in an image. Model-based segmentation has been used in various applications to segment one or multiple target organs from medical images, see for example, the paper by <NPL>. Another segmentation method uses machine learning (ML) models to convert an image into a plurality of constituent shapes (e.g. block shapes or block volumes), based on similar pixel/voxel values and image gradients.

<FIG> shows segmented images showing the LH for a subject at three different time points in a VM. The LH in each image is indicated by the lines 902a, 902b and 902c respectively. <FIG> indicates the LH at rest (baseline measurement). The area of the LH and AP diameter in each image is (a) :<NUM>^<NUM>/<NUM>; (b): <NUM>^<NUM>/<NUM> and (c):<NUM>^<NUM>/<NUM>. In this example, the change in AP diameter compared to the baseline is (b): (<NUM>-<NUM>)/<NUM> = <NUM>% and (c): (<NUM>-<NUM>)/<NUM>=<NUM>%. The change in Area compared to the baseline is (b): (<NUM>-<NUM>)/<NUM> = <NUM>% and (c) (<NUM>-<NUM>)/<NUM> = <NUM>.

Turning back to <FIG>, the method <NUM> may comprise making measurements of the area of the levator hiatus, LH, of the subject in the obtained ultrasound data at a plurality of time points as the subject performs the VM (e.g. measuring the LH in each of a sequence of US images as the VM progresses). The plurality of time points may be at one predefined interval (for example: at <NUM> second intervals throughout the VM). The skilled person will appreciate however that <NUM> seconds is merely an example and that the plurality of time points could be taken at consecutive time intervals of any length. Another simple approach is to select <NUM> representative LH images as first one for the very beginning of the VM, second one located at the middle of the VM, the last one located at either maximal VM time point or closer to the end of the VM.

It has been observed that if a VM is performed correctly, then the LH expands in a predictable manner, e.g. according to a profile. Thus, the shape-profile of the LH during a VM can be analysed to determine whether the VM was performed effectively. Thus, in some embodiments, the method <NUM> may further comprise determining the indication based on a comparison of the measurements of the area of the LH at the plurality of time points with a predefined profile of area measurements of the LH during a VM.

Generally, the predefined profiles may be obtained empirically based on measured profiles of different test subjects. Example predefined profiles that may be used are found in the paper by: <NPL>.

In some embodiments, the International Continence Society Prolapse Quantification System (ICS POP-Q) assessment profiles may be used. This system has <NUM> standardized curves for <NUM> different conditions as following:.

In one embodiment, the measurements of the area of the LH at the plurality of time points can be compared with a predefined profile of area measurements as follows:.

Other image features can also be used to determine whether the VM was performed effectively. For example, in some embodiments, the method <NUM> may further comprise determining from the measurements of the area of the LH, a maximum extent of the LH, LHAMax during the VM and an extent of the LH at rest, LHArest. The indication in step <NUM> may then further indicate whether a percentage change between LHAMax and LHArest is greater than a threshold percentage change. For example, if (LHAMax -LHArest)/LHArest is less than a pre-determined threshold (for example: <NUM>%) then this VM may be ruled out and the indication may indicate that the VM was not performed correctly.

Relative change in levator hiatal dimensions (for example: LH area) may also be used to determine whether the VM has been performed effectively. For example, the relative change between between rest and the maximum point (e.g. labelled as index0 at range from <NUM>% to <NUM>% an example for maximal change in this case) is (LHAMax -LHArest)/LHArest. Index series of relative changes (for example: index1, index2, index3, et. al) at several pressure measurement points can also be computed along the pressure waveform at different time markers. From such index series, a maximal change in measurements can be determined and this can also be used to determine whether the VM is effective or not.

For example, the method <NUM> may further comprise determining from the ultrasound data a maximal change in measurements of the area of the LH with respect to time. The indication in step <NUM> may then further indicate whether the maximal change in measurements of the area of the LH with respect to time is greater than a second predefined threshold. In some embodiments, if the slope is larger than the second predefined threshold and also the abdominal pressure is suitable (e.g. P/Pref > the first predefined threshold) then the VM is considered to have been effectively performed.

In some embodiments, thehiatal anteroposterior (AP) diameter can also be used to determine whether the VM has been performed effectively. For example, step <NUM> may further comprise determining from the ultrasound data a hiatal AP diameter during the VM, and determining from the ultrasound data an anteroposterior diameter at rest. In such embodiments, the indication may further indicate whether the hiatal anteroposterior diameter during the VM is larger than the anteroposterior diameter at rest. This is based on the fact that during an effective/correct VM, the hiatal anteroposterior diameter should be larger than the anteroposterior diameter at rest. As such, this can be indicated to the clinician.

In some embodiments, the bladder neck descent can be used to determine whether the VM has been performed correctly. For example, the bladder neck is expected to descend during correct performance of a VM. As such, in some embodiments, the step <NUM> may further comprise determining from the ultrasound data a measure of bladder neck descent (BND) for the subject during the VM. In such embodiments, the indication may further indicate whether the BND is greater than a predefined threshold BND value.

An appropriate level for the predefined threshold BND value may be determined, for example, empirically from population studies. As another example, the threshold BND value may be set at the symphysis pubis (SP), such that if level of the bladder neck is over the SP, then this is an indication that the VM is effective.

In an example embodiment, in step <NUM>, the following sequence of rules may be used to determine if a VM is effective:.

Turning back to the method <NUM>, in some embodiments, the method may further comprise instructing a display to display the indication on the display for use by a physician in determining whether the obtained ultrasound data is suitable for use in determining whether the subject has pelvic floor dysfunction. Generally, the display may display the data and/or the derived values of any of the indications described above. In some embodiments the indication may further provide advice to the clinician, for example: "The maximum abdominal pressure during the VM is less than <NUM>% of the Reference Pressure recorded for the subject" or "The maximum abdominal pressure during the VM is less than <NUM>% of the Reference Pressure recorded for the subject, the VM needs to be repeated". The indication may indicate that the obtained images are unlikely to be suitable for diagnostic purposes, for example, the indication may provide a warning that if the VM is not performed effectively then there is a risk that a PDF will be missed. The skilled person will appreciate that these are merely examples however and that the indication may be presented on a display in a wide range of different ways.

Thus, using the metrics above, an indication can be provided to a clinician performing a pelvic floor examination, that can be used by the clinician to determine whether the subject has correctly performed a VM, and thus whether the US images obtained are suitable for use in diagnosing PDFs.

Turning now to other embodiments, in one example system, there is an ultrasound system comprising a plurality of computing modules for analysing US image data obtained as a subject performs a VM that comprises some of the elements described above. For example, the computing modules may comprise:.

A user interface to confirm if the LH boundary is well detected.

A third module to obtain the reference abdominal pressure for the subject PRef (e.g. as obtained at home using an apparatus such as the apparatus <NUM> described above) and the abdominal pressure P obtained in the examination room as the subject performs a VM during an ultrasound examination.

A fourth module for determining an indication of whether the VM has been performed correctly. This could determine any of the types of indication described above, for example, a measure of P/Pref and/or one or more of the LH area measurements described above.

A fifth module that, for a given 2D/3D pelvic floor ultrasound image, provides information on the representative 2D/3D image and corresponding shapes for the detected LH (e.g. obtained via segmentation as described above) with useful LH dimensions.

The skilled person will appreciate that this is merely an example illustrating how some of the teachings described herein might be arranged in an ultrasound system, and that other combinations of modules are also possible.

Turning now to other embodiments, as described above with respect to <FIG>, in embodiments herein, the reference abdominal pressure, Pref, is determined for the subject using a sensor external to the body. For example, the sensor may be held against the body by means of a belt <NUM> worn around the waist, or a patch.

More generally, in some embodiments, there is an apparatus <NUM> for use in monitoring a Valsalva Manoeuvre, VM performed by a subject. The apparatus <NUM> comprises a sensor external to the body for measuring abdominal pressure; and a computing apparatus such as the computing apparatus <NUM> described above.

As described above, the sensor may be incorporated into a consumer device. For example, the sensor may be comprised in a belt worn around the subject's abdomen or waist. The sensor may be any type of pressure sensor that can measure force perpendicular to the skin surface. The belt may comprise one or more such pressure sensors and/or sensors for measuring stretch of the belt, e.g. pull/expansion force sensors.

In other embodiments, the pressure sensor may be embedded in a patch stuck to the skin, or a handheld device e.g. on the surface of the stomach against which the subject pushes against.

The computing apparatus may be comprised in (e.g. form part of) a computing device such as a mobile phone, tablet computer, laptop, smart watch, or any other computing device configured to perform the functionality described herein. In some embodiments, the computing apparatus runs a computing application, "app".

The computing apparatus is configured to perform the method <NUM> illustrated in <FIG>. In brief, the computing apparatus is configured to: obtain <NUM> a measurement of abdominal pressure, P, for the subject, from the sensor, whilst the subject is performing a VM. The computing apparatus is further configured to send <NUM> the obtained measurement of abdominal pressure, P, for the subject to an ultrasound system for use by the ultrasound system as a reference abdominal pressure, PRef,,in determining whether the subject has effectively performed the VM.

In some embodiments, the method <NUM> is performed by an app (e.g. on a smartphone, smart watch or similar) that has user interface to guide a subject step by step to remind the subject to perform VM training periodically. This may make the subject more comfortable performing the VM as the subject can practise at home, and may thus provide a more accurate indication of the (true) maximum pressure (PRef) that the subject can achieve during a VM.

The computing apparatus may be configured to give feedback when a subject performs a VM. For example, the computing apparatus may:.

If the subject is doing the expected maximum Valsalva, then the detected pressure is considered as the maximum pressure value. After a period of time training (for example: a week), if the subject has improved their Valsalva capability (e.g. increased their maximal pressure), then a new high maximum pressure value may be set as the target for the subject to achieve in the next week. After <NUM>-<NUM> weeks training, if the maximum pressure value is stable, that that value will be considered as the reference pressure PRef, reflective of the maximal pressure that the subject can obtain. This value of PRef will then be sent (in step <NUM>) be sent for use by the ultrasound system (e.g. for use in the method <NUM> during an ultrasound examination, as described above).

Generally, the apparatus <NUM> may record pressure measurements as the subject performs practice VMs. For example, the apparatus <NUM> may record the maximum pressure measurement of a plurality of VMs performed by the subject. The maximum of the plurality of measurements may then be sent to the US system (e.g. to a hospital/doctors surgery or hospital facility) for use by an US system as the reference pressure, PRef in the method <NUM> as described above.

In this way, the apparatus <NUM> may be used to monitor and record the maximum abdominal pressure achieved by the subject during the VM so as to produce an individualised target pressure PRef that the subject should achieve during the hospital setting, if the VM is performed to the subjects maximal pushing ability. Through the apparatus <NUM>, a subject can be trained to correctly perform the VM through coaching.

In summary, the apparatus described herein can be used to determine the maximal pressure PRef that a subject is capable of exerting on their pelvic floor and this can then be used, in real-time, in an ultrasound system to determine whether US imaging data collected as a subject performs a VM is suitable for use in a subsequent diagnostic process, e.g. suitable for analysing whether the subject has PFD.

Turning now to other embodiments, in another embodiment, there is provided a computer program product comprising a computer readable medium, the computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform the method or methods described herein.

Thus, it will be appreciated that the disclosure also applies to computer programs, particularly computer programs on or in a carrier, adapted to put embodiments into practice. The program may be in the form of a source code, an object code, a code intermediate source and an object code such as in a partially compiled form, or in any other form suitable for use in the implementation of the method according to the embodiments described herein.

Claim 1:
An ultrasound system (<NUM>, <NUM>) for use in monitoring a Valsalva Manoeuvre, performed by a subject, the ultrasound system comprising a computing apparatus (<NUM>) configured to:
receive (<NUM>) a measurement of abdominal pressure for the subject whilst the subject is performing the Valsalva Manoeuvre wherein the measurement of abdominal pressure was measured using a sensor (102a, 102b) external to the body for measuring abdominal pressure; and
determine (<NUM>) an indication of whether the subject has effectively performed the Valsalva Manoeuvre by comparing the measurement of abdominal pressure for the subject whilst the subject is performing the Valsalva Manoeuvre to a reference abdominal pressure measured for the subject.