Inductive sensing system and method

Abstract

An inductive sensing system (8) for detecting bleeding (e.g. blood pools) in one or more regions of a body. The system comprises a resonator circuit (10) having at least one antenna (12) driven with an oscillating drive signal to cause generation of an electromagnetic signal for application to the body. The signal induces eddy currents within the body which generate a secondary EM signal returned from the body. These interact with the resonator circuit by adding an additional inductance component to the circuit. This inductance component varies depending on the conductivity of the fluid in which the eddy currents are induced. Blood has a different conductivity to other bodily fluids. The system is configured to detect the presence of abnormal accumulations of blood based on the additional inductance component. The system generates a data output representative of the determination.

Description

TECHNICAL FIELD

[0001] The present invention relates to an inductive sensing system and method, particularly for sensing the presence of a blood pool in one or more regions of the body. BACKGROUND

[0002] Intracerebral hemorrhage is a major acute disease and requires prompt treatment to prevent rapid deterioration. Two common intracerebral hemorrhages include intracerebral hemorrhage and abdominal hemorrhage.

[0003] Intracerebral hemorrhage (ICH) requires extremely fast treatment; time is a key factor for the prognosis of the patient. The main problem is that ICH is often not immediately recognized in a pre-hospital setting (e.g. in the community, at the patient’s home or in an ambulance). It is often only diagnosed much later, in the hospital, or after the patient has started to decompensate. An earlier correct diagnosis in a pre-hospital setting would facilitate transport to the appropriate facility and allow timely application of therapy if the patient does not suffer from ICH, prevent severe deterioration and also improve the preparation and planning of the correct treatment once the patient has arrived at the hospital. Furthermore, the only known method of ICH diagnosis is currently an expensive in-hospital scan (CT scan or MRI scan), the results of which are evaluated by a neuroradiologist. Although accurate, these scans are both expensive and time-consuming and are not suitable for a pre-hospital setting.

[0004] Therefore, there is still a need for a fast and relatively compact means to reliably diagnose intracerebral hemorrhage in a pre-hospital setting.

[0005] Abdominal pain is one of the most common clinical presentations in emergency departments. The diagnosis of blunt abdominal trauma is crucial for a positive patient outcome. An undiagnosed abdominal hemorrhage can have severe consequences for the patient and can even be fatal. In current practice, the examination for intraperitoneal hemorrhage is performed via manual palpation or using ultrasound waves as part of the focused assessment with sonography in trauma (FAST) method. Although fast, these methods are not accurate. Manual palpation requires the expertise of a medical specialist to reliably determine the extent of abdominal tenderness. Furthermore, even with the input of a medical specialist, it can be that only the liver and the kidneys are palpable, while other organs can be more problematic for diagnosis. Furthermore, the patient is required to consciously indicate tenderness, which can not always be the case in triage situations.

[0006] The FAST technique has made significant progress in recent years and has been used to detect abdominal hemorrhage. However, this modality is also not completely accurate. The acquisition of a diagnostic quality ultrasound image depends on the skill of the operator and is therefore not always reliable. Due to the low sensitivity of ultrasound to intraperitoneal hemorrhage, several diagnostic errors often occur. Visceral hemorrhage is particularly difficult or even impossible to detect using ultrasound waves, which means a significant false negative rate within ultrasound scans. Furthermore, the human interpretation of the ultrasound output is at risk of medical errors.

[0007] As with ICH, the most accurate method remains CT or MRI scans. However, unnecessary computed tomography scans are also not beneficial to patients (exposing them to unnecessary radiation and prolonging their hospital stay) and consume valuable hospital resources. Therefore, to meet the needs of both patients and the emergency department, accurate and timely assessment and triage of potential internal bleeding in trauma patients is required.

[0008] WO 2019 / 094877 describes a device for evaluating intracranial bioimpedance and assessing brain automodulation in a patient’s head.

[0009] Therefore, there is still a need for an accurate and rapid method to detect abdominal bleeding in patients entering the emergency room.

[0010] Therefore, it would be advantageous to have an improved method for detecting internal bleeding that can overcome one or more of the above-mentioned deficiencies. Summary of the Invention

[0011] This invention is defined by the claims.

[0012] According to an example of an aspect of the invention, an inductive sensing system is provided, arranged for sensing an electromagnetic signal returning from the body in response to the application of an electromagnetic excitation signal to the body, the system being adapted to detect the presence of bleeding in one or more areas of the body, the system comprising:

[0013] A resonator circuit includes at least one loop antenna and an electronic signal generator coupled to the antenna, the electronic signal generator being used to drive the antenna using a drive signal to cause the antenna to generate the electromagnetic excitation signal; and

[0014] A signal sensing module is arranged to sense the return signal from the body simultaneously with signal generation based on the detection of a measure indicating an additional inductive component, the additional inductive component being added by the return signal to the antenna of the resonator circuit;

[0015] The system is configured as follows:

[0016] The presence or absence of blood accumulation is determined based on the measurement of the detected additional inductive component; and

[0017] Generate data output indicating the determined result.

[0018] The resonator circuit includes at least two single-loop antennas, and the system is configured as follows:

[0019] detecting an additional inductance component added to each of the antennas by the return signal from the body.

[0020] For example, the system is used for detecting (abnormal) blood pooling, i.e. a collection or accumulation of blood.

[0021] The system can comprise a controller or processor configured to perform the determining and generating steps.

[0022] Embodiments of the invention are thus based on the use of inductive sensing for detecting bleeding.

[0023] According to a set of embodiments, determining the presence or absence of blood accumulation can be based on a predefined threshold value, which is associated with the presence of bleeding or blood accumulation in at least one of the one or more regions of the body. However, the use of a threshold value represents only one example. Alternative methods include for example using an algorithmic model configured to determine the presence or absence of blood in one or more specific regions based on the detected additional inductance component. Other alternative methods can include using for example artificial intelligence or machine learning algorithms, e.g. trained for classifying between normal blood levels in a region and abnormal pooling or accumulation of blood in a region. For example, a machine learning algorithm can be trained with training data comprising different additional inductance component signals for different regions, each signal being labeled as to whether it corresponds to normal blood presence or abnormal blood accumulation or pooling.

[0024] Inductive sensing is based on generating a primary alternating magnetic field via a main antenna loop, which results in induced eddy currents, and a consequent secondary magnetic field in conductive materials or tissue within the primary magnetic field. The interaction of the secondary magnetic field with the primary loop or primary magnetic field can be used to detect characteristics of the probed body, in particular including characteristics of conductive tissue or material, such as water or other fluid content.

[0025] In particular, this field interaction results in a change of a detectable electrical property of the current running through the antenna coil. For example, the current frequency can be changed, and / or the current amplitude can be suppressed.

[0026] In inductive sensing, a signal generator, such as an oscillator, is connected to the loop antenna. The oscillator is an amplifier, typically comprising one or more transistors, which in combination with an inductive source and a capacitive source in a coupled circuit cause a state of resonance. The inductance is provided by the loop antenna, while the capacitance is provided by an optional capacitor component placed in parallel to the loop, together with the loop itself and its environment parasitic capacitance, and the oscillator parasitic capacitance. The total system is referred to as a resonator.

[0027] The secondary magnetic field generated by the body has the effect at the antenna loop of adding an additional complex inductance to the resonator circuit, which thereby causes a detectable change in the circuit current. The real part of the additional inductance can be detected as, for example, a change in the frequency of the oscillator circuit current. The imaginary part of the additional inductance can be detected as, for example, a change in the amplitude of the oscillator circuit current (or voltage).

[0028] Inductive sensing can also be used to distinguish between different fluids in the material. The electromagnetic signal response from different fluids varies depending on their electrical conductivity, which in turn varies depending on their physical properties. This provides a means for detecting the presence of a pool of blood at a location of the body where normally there should be no blood or only a small amount of blood. For example, in an intracerebral region, in a healthy patient, there should only be a layer of cerebrospinal fluid (CSF), plus normal blood flow. In the case of an intracerebral hemorrhage, in addition to or instead of due to an abnormal hemorrhage, there is a pool or accumulation of blood. Similarly, for an abdominal region, for a healthy patient, there should only be abdominal or visceral fluid in addition to normal blood flow through arteries, veins and capillaries in the region. Ascites fluid or visceral fluid has a different electrical conductivity to blood. A pool or accumulation of blood will result in a different returned inductive signal to normal blood flow and normal abdominal and visceral fluid. Thus, by measuring the inductive signal response at the relevant anatomical region, it can be determined whether there is an abnormal accumulation of blood or only normal fluid.

[0029] For example, according to one or more embodiments, the system can be configured for detecting the presence of a blood accumulation in an intracerebral region of the body. The system in this case can be configured for detecting the occurrence of an intracerebral hemorrhage based on the blood detection.

[0030] For example, a signal threshold can be defined, which can be known to be associated with the presence of a hemorrhage in an intracerebral region or an abdominal region as appropriate.

[0031] According to one or more embodiments, the system can be configured for detecting the presence of a blood accumulation in an abdominal region of the body. The system in this case can be configured for detecting the presence of an abdominal hemorrhage based on the blood detection.

[0032] For example, a signal threshold can be defined, which can be known to be associated with the presence of a hemorrhage in an intracerebral region or an abdominal region as appropriate.

[0033] According to one or more embodiments, the system can be configured to switch between at least two detection modes:

[0034] a first detection mode, in which the system is configured for detecting the presence of a blood accumulation in a skull region of the body; and

[0035] a second detection mode, wherein the system is configured for detecting the presence of a blood accumulation in an abdominal region of the body.

[0036] There are different possible configurations for the resonator circuit and the antenna. In particular, the resonator can be provided with a single antenna only or with multiple antennas. In each case, preferably, each antenna comprises only a single loop (single turn or winding).

[0037] It has been found that, in case the resonator circuit is provided with a single antenna only, the largest difference in inductive response between blood and non-blood body fluid is represented in the real part of the additional inductance component added to the resonator circuit.

[0038] Thus, in case a single antenna is provided, the signal sensing module can be configured to detect the real component of the additional inductance component added to the resonator circuit. However, this is not necessary and the approach works, e.g., if instead the imaginary component of the additional inductance is detected.

[0039] In particular embodiments, the detection of the presence or absence of a blood accumulation can comprise comparing the detected real component of the additional inductance with a real inductance threshold associated with the presence of a blood accumulation.

[0040] The use of more than one antenna can improve the accuracy or reliability of the blood detection. In particular, measurements with more than one loop antenna are less sensitive to small changes in the tissue layer between the loop and the fluid. For example, if the fat layer of the abdominal wall varies from patient to patient, the additional inductance measured with a single loop can change due to an increased or decreased distance of the (accumulated) blood layer from the loop. With a multi-loop setup, the measurements of both loops will change, but the ratio between the two measurements will remain approximately stable. Thus, the accuracy of determining the presence of blood is increased.

[0041] In the multi-loop setup, according to certain examples, the system can further be configured to determine a ratio between the additional inductance components added to each of the two antennas and determine the presence or absence of a blood accumulation based on the ratio.

[0042] The ratio in this context can mean the quotient of the reflected inductance components for the two loops.

[0043] In particular examples, the system can be configured to compare the ratio to a predefined threshold to determine the presence or absence of a blood accumulation.

[0044] Thus, in this example, the threshold is predefined, wherein the threshold is a threshold related to the ratio of values between the two loops.

[0045] In other examples, the detection of blood accumulation can be based on a difference between the additional inductance components added to each of the two antennas. For example, this difference can be compared to a predefined threshold to determine the presence or absence of blood accumulation.

[0046] Thus more generally, the detection of blood accumulation can be based on a comparison value of the inductance components added to each of the two antennas.

[0047] It has been found that for a multi-loop setup using a ratio between the inductances added to each loop, the largest difference between the inductance signals for blood and other fluids is found for the imaginary part of the inductances. Thus, in advantageous examples, the signal processing module can be configured to extract the imaginary parts of the additional inductance components added to each of the antennas and determine the ratio between the imaginary parts in these cases. This can provide more accurate or reliable detection results.

[0048] However, the use of imaginary components is not necessary and the method is still applicable to, for example, the real components of the additional inductance components added to each antenna.

[0049] Although examples with two antennas are mentioned, the resonator circuit can comprise more than two antennas.

[0050] In case two or more loops are provided, there are different options for their configuration.

[0051] The two loop antennas can be arranged concentrically with respect to each other.

[0052] Additionally or alternatively, the two loop antennas can be mounted axially offset with respect to each other. Axial offset in this context means an offset in a direction perpendicular to the plane defined by at least one of the antenna loops (the plane in which the antennas are located).

[0053] Additionally or alternatively, the signal generator can be configured to drive the two antennas with driving signals of different respective AC frequencies.

[0054] According to one or more embodiments, the system can comprise a support structure to which the at least one loop antenna is mounted.

[0055] The support structure serves, for example, to hold the one or more antennas in a fixed position. In case there are two antennas, it can hold them in a fixed position with respect to each other. It can be or comprise a frame structure. It is or comprises a housing structure.

[0056] In case a housing is provided, the housing can be arranged to house the resonator circuit comprising the antenna(s).

[0057] According to one or more embodiments, the sensing system can comprise a handheld probe unit. The handheld probe unit can comprise, for example, at least contain or house the resonator circuit.

[0058] The handheld probe configuration allows the system to be used for blood detection at different areas of the body, including the head or abdomen, as required. For example, the system can be switchable between different detection modes, for example as described above, for use in relation to different areas of the body.

[0059] According to one or more embodiments, the system can comprise a head-mounted cap to which at least one antenna is mounted. The mounting can be such that when the cap is worn, the at least one antenna is held in a fixed relationship with the surface of the head.

[0060] In preferred examples, preferably the system can comprise a plurality of antennas mounted to the cap at different locations so as to be held at different locations around the head when the cap is worn.

[0061] Such a cap provides an effective arrangement for detecting bleeding in the head region, for example for detecting intracerebral haemorrhage. The provision of a plurality of antennas at different locations around the cap means that bleeding across the full head region can be monitored, and for example a map of the signals detected around the head can be monitored.

[0062] In some examples, the cap can be formed of a flexible material so as to be held around the head when worn. However, this is not essential.

[0063] According to one or more embodiments, the system can comprise a garment or bed sheet (for example a textile) for covering at least one of the one or more regions of the body, to which the at least one antenna is mounted.

[0064] In preferred embodiments, the system can comprise a plurality of antennas mounted to the garment or bed sheet at different locations.

[0065] According to specific examples, the garment or bed sheet can comprise a blanket or vest.

[0066] A garment or bed sheet can be particularly advantageous for detecting bleeding in the abdominal region. For example, a blanket can be placed across the abdomen of the patient, whilst providing an insulating function, and also enabling inductive detection of any blood pooling in the abdomen.

[0067] According to one or more advantageous embodiments, the garment or bed sheet can comprise a visual indicator module, the system being configured to control the visual indicator module to provide a visual indication of the determination of the presence or absence of blood. The visual indicator can for example comprise one or more light sources, for example a red light and a green light, for example indicating the presence of blood and the absence of blood respectively. This feature can additionally or alternatively be applied to the head-mounted cap mentioned above to provide a visual indication of the presence of blood.

[0068] An example according to another aspect of the application provides an inductive sensing method for detecting the presence of bleeding in one or more regions of a patient's body, the method being based on sensing an electromagnetic signal returned from the body in response to applying an electromagnetic excitation signal to the body, the method comprising:

[0069] driving at least two loop antennas of a resonator circuit with a drive signal such that each loop antenna generates the electromagnetic excitation signal;

[0070] sensing the returned signal from the body based on detecting a measure indicative of an additional inductance component added to each of the antennas of the resonator circuit by the returned signal, simultaneously with the generation of the signal;

[0071] determining the presence or absence of blood accumulation based on the detected measure of the additional inductance component, and

[0072] generating a data output indicative of the result of the determination.

[0073] In particular embodiments, determining the presence or absence of blood accumulation or pooling can be based on a predefined threshold value associated with the presence of (abnormal) blood accumulation in at least one of the one or more regions of the body.

[0074] The method can be used to detect the presence of blood accumulation in an intracranial region. The method can be used to detect the presence of blood accumulation in an abdominal region. The method can further comprise determining the occurrence of either an intracranial hemorrhage or an abdominal hemorrhage based on the blood detection.

[0075] For example, the method can comprise positioning at least one antenna of the resonator circuit for applying an electromagnetic excitation signal to the head region or the abdominal region, and receiving a returned electromagnetic signal from the head region or abdominal region.

[0076] In case a threshold value is used for the detection, the threshold value can be a threshold value known to be associated with the presence of bleeding in the cranial region or the abdominal region as appropriate.

[0077] An example according to another aspect of the present application can provide a computer program product comprising code means configured, when run on a processor, to cause the processor to operatively couple to:

[0078] a resonator circuit comprising at least one loop antenna, and an electronic signal generator coupled to the antenna for driving the antenna with a drive signal to cause it to generate the electromagnetic excitation signal, and

[0079] a signal sensing module arranged for sensing the return signal based on detecting a measure indicative of an additional inductance component added to the antenna of the resonator circuit by the return signal from the body, simultaneously with the signal generation, to cause the processor to perform an inductive sensing method according to any of the embodiments outlined above or described below or according to any claim of the present application.

[0080] These and other aspects of the present application will be apparent from and elucidated with reference to the embodiments(s) described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0081] For a better understanding of the present application, and to show how it can be implemented, reference will now be made, purely by way of example, to the accompanying drawings in which:

[0082] Figure 1 schematically illustrating eddy current induction within a body to which the system is applied;

[0083] Figure 2 showing a schematic block diagram of components of an example system according to one or more embodiments;

[0084] Figure 3 illustrating an example arrangement comprising two antennas;

[0085] Figure 4 and Figure 5 showing graphs illustrating comparative inductive responses for blood and CSF for the imaginary and real parts of inductance when using a single antenna, respectively;

[0086] Figure 6 and Figure 7 showing graphs illustrating comparative inductive responses for blood and CSF for the imaginary and real parts of inductance when using two antennas, respectively;

[0087] Figure 8 and Figure 9 schematically illustrating a head-mounted cap unit comprising a plurality of antennas mounted thereto;

[0088] Fig. 10 shows a closer view of an attachment module for an antenna to a head cap;

[0089] Figure 11 An example bed sheet or garment is schematically illustrated including a plurality of antennas mounted thereto; and

[0090] Figure 12 An example method according to one or more embodiments is outlined in block diagram form. DETAILED DESCRIPTION

[0091] The application will be described with reference to the accompanying drawings.

[0092] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of apparatuses, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the application. These and other features, aspects, and advantages of the apparatuses, systems and methods of the present application will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0093] The present application provides an inductive sensing system for detecting bleeding (e.g. blood pools) in one or more regions of a body. The system includes a resonator circuit having at least one antenna driven with an oscillating drive signal to cause generation of an electromagnetic signal for application to the body. The signal induces eddy currents within the body, which generate a secondary EM signal returned from the body. These interact with the resonator circuit by adding an additional inductance component to the circuit. This inductance component varies depending on the conductivity of the fluid in which the eddy currents are induced. Blood has a different conductivity to other bodily fluids. The system is configured to detect the presence of blood based on the additional inductance component. The system generates a data output representative of the determination.

[0094] As discussed, the present application is based on inductive sensing technology.

[0095] Inductive sensing can be used as a means for non-invasive investigation of body properties.

[0096] Inductive sensing is based on generation of a primary alternating magnetic field via a primary antenna loop, which results in induced eddy currents and consequent secondary magnetic fields in conductive materials or tissue within the primary magnetic field. The interaction of the secondary magnetic field with the primary loop or primary magnetic field can be used to detect patterns of motion of the probed body, including those patterns that include water content, in particular.

[0097] In particular, the field interaction results in a change in a detectable electrical property of the current extending through the antenna coil. For example, the current frequency can be changed, and / or the current amplitude can be suppressed.

[0098] In inductive sensing, a signal generator (such as an oscillator) is connected to a loop antenna. The oscillator is an amplifier, usually comprising one or more transistors, which in combination with an inductive source and a capacitive source in a coupled circuit cause a state of resonance. The inductance is provided by the loop antenna, while the capacitance is provided by an optional capacitor component placed in parallel with the loop, together with the loop itself and its environment's parasitic capacitance, and the oscillator's parasitic capacitance. This total system is referred to as a resonator.

[0099] The secondary magnetic field generated by the body has the effect at the antenna loop of adding an extra complex inductance to the resonator circuit, which in turn causes a detectable change in the circuit current. The real part of the extra inductance is detectable as, for example, a change in the frequency of the oscillator circuit current. The imaginary part of the extra inductance is detectable as, for example, a change in the amplitude of the oscillator circuit current (or voltage).

[0100] Inductive sensing is based on generating a primary alternating magnetic field via a main antenna loop, which causes induced eddy currents; and consequent secondary magnetic fields in conductive materials or tissue within the primary magnetic field. This is illustrated schematically in Figure 1 The loop antenna 12 of the resonator circuit is driven with an alternating current (drive signal). This causes the current in the antenna to oscillate.

[0101] In use, the antenna 12 is brought into proximity with a body 16 to be probed. The drive of the antenna generates a primary electromagnetic (EM) signal 22 which couples with the body and generates eddy currents 18 in the body. These eddy currents depend on the electrical conductivity of the body. The eddy currents generate a secondary magnetic field 24. This secondary field interacts with the primary field 22 to change the oscillation characteristics of the resonator circuit.

[0102] In particular, generally, when the loop antenna reaches proximity to the body, the inductance L picks up an extra reflected inductance component L r as a result of the application of the excitation signal 22.

[0103] These eddy currents 18 in turn effectively make a contribution to the inductance of the loop antenna 12 due to the generation of the secondary time-varying magnetic flux. These eddy current fluxes combine with the main flux of the antenna, which results in a greater induced counter-EMF in the antenna, and hence a greater measurable effective inductance.

[0104] The added component of inductance due to the eddy currents can be referred to synonymously in this disclosure as "reflected inductance".

[0105] Generally, the reflected inductance L r is complex, and can be expressed as:

[0106] L r = L' r +iL" r (1)

[0107] where L' r is related to the reactive impedance of the antenna, and L" r is related to the resistive impedance of the antenna.

[0108] the inductance L r The addition of the reflected component of the inductance L r results in a detuning of the properties of the antenna (or resonator circuit). In particular, both the natural radial frequency of the coil antenna circuit and the damping factor of the coil antenna circuit change.

[0109] In particular, the real part of the additional inductance component L r is manifested in the natural frequency of the resonator circuit or antenna. The imaginary part of the additional inductance component is manifested in the (natural) oscillation amplitude of the resonator circuit.

[0110] By way of completeness, it should be noted that the circuit inductance is electrically related to the circuit impedance, and thus the measurement of the real and imaginary parts of the impedance can in some examples provide an indication of the required measured imaginary and real inductance. In particular, the impedance Z comprises a real part and an imaginary part: Z = R + iX, where R is the resistance and X is the reactance. This can also be written as Z = R + iω*L, where ω is the radial frequency and L is the inductance.

[0111] The above-mentioned reflected inductance L r can be defined as:

[0112] Lr = Z / (iω) = L - iR / ω (= L' + iL"). In this case, L is then referred to as the real part of the reflected inductance (also denoted as L'), and -R / ω is referred to as the imaginary part of the reflected inductance (also denoted as L").

[0113] Inductive sensing can also be used to distinguish between different fluids in a material. The electromagnetic signal response from different fluids varies depending on their electrical conductivity, which in turn varies depending on their physical properties. This provides a means for detecting the presence of a blood pool at a location in the body where normally there should be no blood or only normal blood flow.

[0114] For example, in the cranial or intracerebral region, in a healthy patient, there should only be a layer of cerebrospinal fluid (CSF), and normal blood flow through the blood vessels in the region. In the case of an intracerebral hemorrhage, there is additionally an accumulation or pooling of blood. Blood and CSF have different electrical conductivities. Thus, in the presence of blood pooling or accumulation, the average electrical conductivity of the probe region changes due to being greater than the normal blood concentration in the region. Thus, by measuring the inductive EM response of an intracerebral region, for example, it can be determined whether there is a blood accumulation or only normal blood and CSF.

[0115] Similarly, for the abdominal region, for a healthy patient, there should only be abdominal or peritoneal fluid in addition to normal blood flow through the blood vessels. Peritoneal or peritoneal fluid has a different electrical conductivity than blood. Thus, the inductive response of an inductive sensor applied to the abdominal region allows detecting the presence of a blood accumulation compared to the presence of only normal levels of blood plus abdominal or peritoneal fluid. As mentioned above, when there is an abnormal bleeding and thus blood pooling, the average electrical conductivity of the probed region changes, resulting in a change in the inductive response. This allows distinguishing an abnormal blood accumulation from a normal blood flow combined with other normal fluids.

[0116] Embodiments of the present application thus use inductive sensing to detect blood accumulation based on these principles.

[0117] Figure 2 A sensing system according to one or more embodiments of the present application is shown in block diagram form.

[0118] The system 8 comprises a resonator circuit 10 comprising a loop antenna 12 and an electronic signal generator 14 coupled to the antenna for driving the antenna with a drive signal so that it generates an electromagnetic (EM) excitation signal. The signal generator in this example takes the form of an oscillator 14 which generates a drive signal having a drive frequency.

[0119] In this example, the resonator circuit 10 further comprises a capacitor 13 for setting or tuning the natural free-space resonance frequency of the resonator circuit (i.e. the natural frequency in the absence of any applied field). In some examples, the capacitor can be a variable capacitor to allow adjustment of the natural free-space resonance frequency.

[0120] The system 8 further comprises a signal sensing module 30 arranged for sensing a return signal from the body based on detecting a measure indicative of an additional (complex) inductance component added to the antenna 20 of the resonator circuit 10 by the return signal from the body at the same time as the signal generation.

[0121] The secondary EM signal from the body adds an additional (complex) inductance component to the circuit, as discussed above. This can be detected based on detecting a change in one or more electrical properties of the resonator circuit, for example by detecting a change in the natural damping factor of the resonator circuit and / or a change in the natural frequency of the resonator circuit. These can be detected based on detecting a change in the amplitude of the oscillations in the resonator circuit current or based on detecting a change in the frequency of the oscillations in the resonator circuit, respectively, for example. The additional inductance component will vary depending on the properties of the probed medium, as discussed above.

[0122] The system is further configured to determine the presence or absence of a blood accumulation based on the detected measure of the additional inductance component.

[0123] The system is further configured to generate a data output indicative of the determined result.

[0124] In some examples, the determination of the presence or absence of blood, for example, can be based on one or more predefined thresholds, the one or more thresholds being associated with the presence of bleeding in at least one of the one or more regions of the body. In this way, bleeding can be detected.

[0125] However, the use of thresholds is not essential. Alternative approaches include, for example, the use of an algorithmic model configured to determine the presence or absence of blood in one or more specific regions based on the detected additional inductance component. Other alternative approaches can also include the use of, for example, artificial intelligence or machine learning algorithms, for example trained for classification between normal blood levels in a region and abnormal pooling or accumulation of blood in a region. For example, a machine learning algorithm can be trained with training data comprising different additional inductance component signals for different regions, each signal being labelled as to whether it corresponds to normal blood presence or abnormal accumulation or pooling of blood.

[0126] The above merely represents example approaches and embodiments of the invention are not limited thereto.

[0127] In some examples, the system can comprise a controller or processor configured to perform said determining and generating steps.

[0128] In Figure 2 In examples, the system 8 further comprises a microprocessor 32 arranged to be operatively coupled to the signal sensing module 30 and the resonator circuit 32. For example, the microprocessor can be configured for controlling the drive frequency of the drive signal generator 14 and / or it can be configured to perform signal processing, for example for said determination of the presence or absence of bleeding. In some examples, it can perform further signal processing, for example to derive one or more physiological or anatomical parameters from the sensed or measured signals detected by the signal sensing module 30.

[0129] The signal sensing module 30 can take different forms and operate in different ways for deriving said measure indicative of the additional inductance component added to the antenna of the resonator circuit by said return signal.

[0130] The inductive sensing system can be configured in either a single antenna arrangement or a multiple antenna arrangement.

[0131] In a single antenna arrangement, the resonator circuit comprises only a single antenna, preferably with a single loop.

[0132] In a multi-antenna setup, the resonator circuit comprises two or more antennas, each driven with a drive signal to generate an excitation signal, and wherein an additional inductance component added to each respective antenna is sensed by the signal sensing module.

[0133] Figure 3 An example multi-antenna configuration is schematically illustrated. In this example, two antennas are provided, a first 12a larger diameter antenna, and a second 12b smaller antenna diameter. In the illustrated example, the two antennas are arranged concentrically, with the smaller antenna 12b embedded (e.g. coaxially) within the circumference of the larger antenna 12a. A support structure, e.g. a frame or housing, can be provided which is arranged to hold the two (or more) antennas fixed relative to each other.

[0134] In this example, the two antennas are arranged coplanarly, i.e. in the same plane. However, in other examples, the two or more antennas can be mounted axially offset from each other (i.e. in a direction perpendicular to the plane defined by at least one of the antennas).

[0135] Furthermore, a concentric arrangement is not necessary. In further examples, the second antenna 12b can be arranged outside the circumference of the first antenna 12a, or its inner loop surface area can overlap with the inner loop surface area of the first antenna.

[0136] Furthermore, according to one or more examples, the two or more antennas can each be driven with a drive signal of a different respective frequency. This will be discussed further below.

[0137] Single and multi-antenna configurations will now be described in more detail.

[0138] A single antenna 12 can be used to measure a reflected inductance, e.g. at a specific location of the skull or abdominal region. For example, a single loop placed on the skull can be used to detect an intracerebral hemorrhage. A single loop placed on the abdomen can be used to detect an abdominal hemorrhage, e.g. caused by an abdominal trauma. Examples related to the detection of an intracerebral hemorrhage will be considered below.

[0139] The value of the reflected inductance will vary based on the tissue close to the loop antenna 12, the geometry of the loop, and the position of the loop relative to the body, e.g. the distance to the body. The term “reflected inductance” has been introduced above and refers to an additional inductance component added to the resonator circuit by a secondary electromagnetic (EM) signal returned from the body in response to the application of the EM excitation signal.

[0140] Since blood is more conductive compared to cerebrospinal fluid (CSF) or abdominal and internal body fluids, the presence of blood will result in a higher reflected inductance. By measuring the exact value of the reflected inductance, it can be determined whether there is more blood present than would be expected normally, or whether blood is present where it should not be. In this way, inductive sensing can be used to detect internal bleeding in the abdominal region or in the brain.

[0141] For example, according to a set of possible embodiments, a predetermined detection threshold can be defined in relation to the reflected inductance component, which threshold is known to be associated with the presence of bleeding, i.e. to detect an abnormal accumulation or pooling of blood in the anatomical region under consideration. The system can be configured to compare the detected reflected inductance component obtained with the single loop to the threshold to determine whether there is bleeding or no bleeding (abnormal blood pooling, or normal amount of blood). The value of the threshold can vary depending on the region of the body under consideration. For example, a different threshold can be defined for detecting intracerebral bleeding compared to detecting abdominal bleeding. The threshold can be predetermined, e.g. based on empirical measurements or based on the use of a model or simulation.

[0142] It should be noted that in some cases, a threshold can not be needed, and a model or simulation can be applied directly to determine the presence or absence of blood accumulation, e.g. by feeding the measured additional inductance component as input to the model or simulation.

[0143] To illustrate the principle of blood detection with a single loop arrangement, the inventors have run a paradigm simulation for detecting intracerebral bleeding.

[0144] Figure 4 and Figure 5 The difference in the real part (y-axis of Fig. 40) and the imaginary part (y-axis of Fig. 41) of the reflected inductance is shown when there is a thin layer of blood or CSF behind the skull as a function of the (normalized) frequency (x-axis of Figs. 40 and 41). Each graph shows the results for both blood and CSF. In Fig. 40, line 42 shows the results for CSF, and line 44 shows the results for blood. In Fig. 41, line 52 shows the results for CSF, and line 54 shows the results for blood. Figure 4 Figure 5 In each graph, the frequency is normalized with respect to the loop diameter. This normalization method is discussed in detail in WO 2018 / 127482. Figure 4 Figure 5 From the graphs of Figs. 40 and 41, it is clear that the presence of blood behind the skull results in a reflected inductance 54 (Fig. 41) that is different from the reflected inductance 52 (Fig. 40) for CSF. In particular, the real part of the reflected inductance is larger for blood than for CSF, and the imaginary part of the reflected inductance is smaller for blood than for CSF. Figure 4 Figure 5 In Fig. 40, the difference between the real part of the reflected inductance for blood and for CSF is larger than the difference between the imaginary part of the reflected inductance for blood and for CSF. In Fig. 41, the difference between the imaginary part of the reflected inductance for blood and for CSF is larger than the difference between the real part of the reflected inductance for blood and for CSF.

[0145] In each graph, the frequency is normalized with respect to the loop diameter. This normalization method is discussed in detail in WO 2018 / 127482.

[0146] From the graphs of Figs. 40 and 41, it is clear that the presence of blood behind the skull results in a reflected inductance 54 (Fig. 41) that is different from the reflected inductance 52 (Fig. 40) for CSF. In particular, the real part of the reflected inductance is larger for blood than for CSF, and the imaginary part of the reflected inductance is smaller for blood than for CSF. Figure 4 Figure 5 In Fig. 40, the difference between the real part of the reflected inductance for blood and for CSF is larger than the difference between the imaginary part of the reflected inductance for blood and for CSF. In Fig. 41, the difference between the imaginary part of the reflected inductance for blood and for CSF is larger than the difference between the real part of the reflected inductance for blood and for CSF.​​​​Figure 5 ) a significantly higher real component. The difference between the results for blood 44 and CSF 42 can also be observed in the imaginary component of the reflected inductance ( Figure 4 ), but the difference in results is smaller. Thus, for a single antenna setup, detecting the real component of the reflected inductance can provide more reliable and robust blood accumulation detection results.

[0147] For example, in an advantageous example, the system 8 can be configured to detect an additional real inductance component added to the resonator circuit and determine whether this exceeds a predetermined threshold, wherein the predetermined threshold can be based on a known value (or as a function of frequency) detected for a normal fluid such as CSF or a known normal blood flow level in a given region other than CSF.

[0148] Since the real component of the inductance is related to the imaginary component of the impedance, optionally, in some advantageous embodiments, the system 8 can be configured to detect an additional imaginary impedance component added to the resonator circuit and determine whether this exceeds a predetermined threshold, wherein the predetermined threshold can be based on a known value (or as a function of frequency) detected for a normal fluid such as CSF or a known normal blood flow level in a given region other than CSF.

[0149] The layer model used for the simulation in this example comprises the following layers and corresponding thicknesses (in mm):

[0150] Layer Thickness (mm) Bone - Cortical 2 Bone - Cancellous 3 Bone - Cortical 2 Cerebrospinal Fluid / Blood 1 Grey Matter 5 White Matter 100 Air Infinite

[0151] Table 1

[0152] It is assumed that the loop is placed at a distance of 3 mm from the first layer of cortical bone, which corresponds to, for example, the actual value of the outer wall of the probe housing between the loop and the skull.

[0153] A multi-loop arrangement will now be discussed.

[0154] According to one or more embodiments, a multi-loop setup comprising two or more antennas, preferably each comprising a single loop or winding, can be provided. Each can be provided with a different geometry (e.g. diameter, shape), position relative to the body (e.g. distance) and / or can be driven with a different driving frequency.

[0155] The multi-loop setup can be used for detecting bleeding in any region of the body, including, for example, for detection of intracerebral hemorrhage and for abdominal bleeding.

[0156] When the measurements of more than one antenna are combined, the measurements become less sensitive to small changes in the organization of the near loop. For example, if the fat layer of the abdominal wall varies from patient to patient, the reflected inductance measured with a single antenna will change due to an increased or decreased distance of the blood layer to the loop. However, with a multi-loop setup, the measurements of both antennas will change, but the ratio between the two measurements will more or less remain stable. Thus, the accuracy of the blood presence detection is increased.

[0157] This also advantageously means that no calibration of the system between different patients is required, since although the absolute measurement of the additional inductance (at a single antenna) can vary from patient to patient, the ratio between the values of the two loops is relatively stable across most patients. Thus, the accuracy is increased without the need for patient-specific calibration.

[0158] Similarly, when using a multi-loop setup to detect intracerebral hemorrhage, changes in the thickness of the skull have minimal influence on the ratio of the reflected inductance, whereas the results for a single loop can vary.

[0159] Thus, in a multi-loop arrangement, the system can be configured to detect an additional inductance component added to each of the plurality of antennas by the return signal from the body.

[0160] In some embodiments, the system can also be configured to determine a ratio between the additional inductance components added to each of the two antennas, and compare the ratio to a predefined threshold (for the ratio) to determine the presence or absence of blood. In other examples, a difference between the inductance components added to each of the two antennas can be determined, and this compared to a predefined threshold for the difference. More generally, a comparison value of the additional inductance components of the two antennas can be used for the determination.

[0161] A predetermined threshold can be defined in relation to the ratio of the reflected inductance component values between the two (or more) loops. The ratio can be specific to the loop arrangement. For example, it can correspond to the ratio of the smaller loop 12b to the larger loop 12a. The ratio in this context means the quotient of the reflected inductance component values for the two loops. The ratio threshold can be a ratio known to be associated with the presence of abnormal accumulation or pooling of blood.

[0162] The ratio threshold can be predetermined based on empirical measurements, or can be based on, for example, a model or simulation.

[0163] To illustrate the multi-antenna setup, the inventors have run further simulations, the results of which are shown in Figure 6 and Figure 7in the figures. Simulations are run with the same tissue layers used in the single loop setup simulations (i.e. as indicated in Table 1 above). The setup comprises two concentric loops with diameters of 10 mm and 20 mm, respectively (e.g. as shown in Figure 3 Fig. 2), and configured in a coplanar arrangement such that the distance from the antennas to the skull is the same for both antennas. These diameter sizes are merely by way of example, and in further examples any other antenna diameter values can be used in the opposite.

[0164] The ratio between the measured reflected inductances of the two loops is plotted as the imaginary part of the inductance (y-axis of Fig. 3) and the real part of the inductance (y-axis of Fig. 4) as a function of frequency (x-axis of both Fig. 3 and Fig. 4). Figure 6 Figure 7 The ratio in each case corresponds to the inductance value of the smaller loop (Loop 1) divided by the inductance value of the larger loop (Loop 2), i.e. the quotient of the smaller loop and the larger loop. Figure 6 Figure 7 Each graph shows the ratio results for both CSF and blood. In Fig. 3, line 62 shows the results for CSF and line 64 shows the results for blood. In Fig. 4, line 72 shows the results for CSF and line 74 shows the results for blood.

[0165] In this case, the largest difference between the blood and CSF results is found in the ratio of the imaginary components of the reflected inductances (Fig. 3). Figure 6 Here, the ratio between the imaginary reflected inductance components of the two loops (Loop 1 / Loop 2) is significantly smaller for blood than for CSF. Figure 7 Therefore, in some embodiments, the system 8 can be configured to extract the imaginary components of the reflected inductance components added at each antenna and determine only the ratio or quotient between these imaginary components. Working on the imaginary components for the ratio can result in more reliable or accurate detection results.

[0166] Figure 6 Also, since the imaginary components of the inductance are related to the real components of the impedance, alternatively, in some advantageous embodiments, the system 8 can be configured to extract the real parts of the additional impedance components added at each antenna and determine the quotient or ratio between these real components of the impedance.

[0167] However, differences are also observable between the ratio results of the real components of the reflected inductances (Fig. 4).

[0168] Therefore, in further embodiments, the ratio of the real components of the reflected inductances can alternatively or additionally be used in a multi-loop arrangement.

[0169] Figure 7

[0170] ​​​​​Although arrangements comprising only two antennas (two loops) have been discussed, in further embodiments more than two antennas (two loops) can be provided. In some embodiments, the detection of blood accumulation can be based on the relative values of the additional inductance components added to each of the three of the more antennas. For example, the difference between the inductance components of different pairs of the three of the more loops can be calculated, or the average difference between the loops can be calculated, or the quotient between the inductance components of the three of the more loops can be calculated. In some examples, the difference between the inductance components of different pairs of the three or more antennas can be calculated, and a common baseline or offset (e.g. representing skull thickness) known to be present in each can be subtracted. This can allow the compared values to more reliably indicate differences in blood volume in different regions.

[0171] Furthermore, although the above arrangements comprise concentric and coplanar antennas, in further embodiments the antennas can be provided in an axial offset and / or non-concentric arrangement from each other.

[0172] According to one or more embodiments, the two or more loops can be driven with different respective driving frequencies of the driving signals. This can further enhance the robustness of the measurement, as different frequencies will vary to different extents as a function of varying layer thickness. Thus, the reflected inductance ratio of two loops driven at different frequencies will tend to be more consistent between different patients than a two-loop arrangement in which the two loops are driven at the same frequency.

[0173] According to one or more embodiments, one or both loops can be driven at a time-varying frequency. For example, the frequency can be varied in a continuous manner (i.e. a frequency sweep is performed), and / or the frequency can be changed in discrete steps. The strength of the signal response (at the desired measurement depth) can vary depending on the driving frequency. Thus, by performing a frequency sweep, the optimal frequency (providing the strongest signal response) can be identified.

[0174] As discussed above, for either a single or multiple antenna arrangement, according to a set of embodiments a threshold can be used for blood detection. The value of the threshold can vary depending on the region of the body under examination. For example, there can be a different threshold for an intracerebral region compared to an abdominal region. As also discussed above, the use of a threshold is not essential, and for example other algorithms or models or machine learning based detection methods are also possible.

[0175] According to one or more embodiments, the system can be switchable between at least two detection modes:

[0176] a first detection mode, in which the system is configured for detecting the presence of blood accumulation in an intracerebral region of the body; and

[0177] A second detection mode, in which the system is configured for detecting the presence of blood accumulation in the abdominal region of the body.

[0178] Both single loop and multi-loop arrangements can be implemented in different ways.

[0179] In either case, a support structure can be provided for holding one or more antennas of the resonator circuit in a fixed position, for example in a fixed relationship to each other. Various example support structures will now be outlined.

[0180] According to one or more embodiments, the sensing system can comprise a handheld probe unit comprising at least a resonator circuit. In this case, the handheld probe can comprise a housing or frame providing the support structure.

[0181] A generic handheld device with either a single loop or multi-loop arrangement can be used for probing the skull and torso (and any other desired body region). A module can be provided for inputting to the device the anatomical region it is used with, for example the skull or torso, or other region. In case a threshold is used for performing the detection of blood pooling, it can then configure the threshold setting based on this input. The device can be provided with a module for automatically detecting the region it is sensing, for example a position sensor. Alternatively, there can be a user input module for providing this information to the probe. For example, this can be a simple switch for switching between different modes for different regions, for example a skull mode or a torso mode. In some examples, this can be a "software switch" implemented by a control unit or processor of the device or system.

[0182] In some examples, the system can be configured to automatically select the mode based on the inductance signal values detected at the region where the probe is placed. For example, an initialization phase can be triggered for automatically configuring the correct mode. The handheld unit is placed at the anatomical region to be probed and the initialization phase is activated. The system starts generating the inductive sensing signal and based on, for example, the value of the additional inductance component measured at the antenna, it can determine which anatomical region is being probed. For example, a lookup table can be stored which records typical ranges of inductive signal (e.g. additional inductance component) values for different anatomical regions. Based on consulting such a table, the anatomical region position of the device can be estimated and the correct mode for that region is automatically selected.

[0183] According to another set of embodiments, the system 8 can comprise a head-mounted cap to which at least one antenna is mounted. Preferably, a plurality of antennas 12 can be provided mounted to the cap.

[0184] Figure 8 Examples are schematically illustrated. Figure 8An example head cap 82 is shown which comprises a plurality of antennas 12 mounted or coupled to the outer surface of the cap (i.e. the surface furthest from the head when worn). The cap or hat can be placed on the patient's head when in use and the single or multiple antenna loops measure the reflected inductance at a plurality of locations on the skull. This gives the clinical staff the benefit of not having to hold the device. This can be beneficial for example in an ambulance. The cap can also ensure that the antennas are held in stable positions relative to the head and for example maintain a fixed uniform distance between each other. This can be beneficial for reliable and comparable measurements between test instances and between patients.

[0185] The cap can be configured in such a way that the positions of the antennas are fixed relative to the head and the spacing or pitch of each inductive sensor relative to the skull is uniform across the skull.

[0186] This can be done for example by using a flexible cap so as to ensure that contact with the skull is maintained (the cap remains around the head when worn). Optionally, a plurality of holes can be delineated by the cap so that the cap takes the form of a net or grid.

[0187] In a preferred example, each single or multiple antenna can be connected to the flexible cap or flexible net at a single point. Thus, even if the loop is rigid, the cap itself is completely flexible.

[0188] This is shown in Figure 9 and Figure 10a and Figure 10b Figure 9 An example cap 82 is illustrated and shows the arrangement of a plurality of single antennas 12 mounted to the cap, each antenna 12 via a single connection point 102. Each antenna is mounted to the outer surface of the cap or net via a spacer member 102 which holds or keeps each antenna upright or above the outer surface of the cap, hat or net (i.e. the surface facing away from the head). Each spacer member takes the form of a rod or bar which holds the respective antenna above the outer surface of the cap.

[0189] The spacer 102 or rod ensures that the centre of the circumference of the antenna loop 12 is held at a constant distance from the outer surface of the cap. In a further example, the spacer can be provided in the form of a cladding of wires around the antenna.

[0190] Figure 9 The array of inductive sensor antennas shown in

[0191] ​In a set of advantageous examples, the cap 82 can comprise a visual indicator module, and wherein the system is configured to control the visual indicator module to provide a visual indication of the determination of the presence or absence of bleeding in the region of the brain (e.g. in the brain).

[0192] The indicator can for example comprise a red-green light or display attached to the cap 82, e.g. red indicating bleeding, green indicating no bleeding.

[0193] The cap can be operably connectable in use, e.g. wired or wirelessly to a readout device or patient monitor.

[0194] Figure 10 shows an example antenna 12 and coupled spacer 102 or pole (single point connector). Figure 10b Figure shows a view of the spacer 102 or pole itself.

[0195] According to a further set of embodiments, the system can comprise a (e.g. textile) garment or bed sheet for covering one or more regions of the body to be inductively sensed, wherein at least one antenna 12 is mounted to the garment or bed sheet.

[0196] Preferably, the system comprises a plurality of antennas mounted to the garment or bed sheet at different locations.

[0197] Such an arrangement is particularly advantageous for performing inductive sensing of the torso (e.g. abdomen) for example.

[0198] According to one or more examples, a blanket or vest can be provided which can be placed on a patient, the blanket or vest comprising a plurality of antennas 12 mounted thereto.

[0199] Figure 11 An example is shown schematically. This shows an example blanket article 92 comprising an array of antennas 12 mounted on regions thereof. These can be mounted on the outer surface of the blanket, or can be integrated in the main body of the blanket, e.g. sewn in or zippered in.

[0200] The blanket 92 can for example be placed on a patient during a measurement, enabling medical personnel to focus on other tasks.

[0201] In a set of advantageous examples, the blanket can comprise a visual indicator module, and wherein the system is configured to control the visual indicator module to provide a visual indication of the determination of the presence or absence of bleeding in the abdominal region.

[0202] The indicator can for example comprise a red-green light or display attached to the blanket, e.g. red indicating bleeding, green indicating no bleeding.

[0203] In one set of embodiments, the visual indicator module can be arranged to detect blood accumulation across multiple regions of the patient's body, which can be covered by a garment or bed sheet (e.g. blanket). The visual indicator module can comprise a plurality of visual indicator portions arranged to provide a visual indicator at different locations of the garment or bed sheet to indicate the corresponding body location of detected blood pooling. For example, the visual indicator module can comprise a plurality of light sources disposed at different locations across the bed sheet or garment, and wherein the system is configured to illuminate the light source at a location aligned with (e.g. positioned on top of) any location of the body at which the plurality of antennas of the garment or vest detect blood accumulation.

[0204] For example, a location on the garment or vest on the patient can be calibrated, such as the center of the top edge of a blanket-like article positioned at the sternal notch or xiphoid process. The clinician can ensure that the reference point on the garment or vest is correctly aligned with the predefined reference on the patient's body when positioning the garment or vest on the patient. In this way, the article is positionally calibrated.

[0205] Similar features can also be applied to the head-mounted cap 82 discussed above, i.e. the head-mounted cap can comprise a visual indicator module arranged to provide a visual indicator at different locations of the cap to indicate the corresponding brain location of detected blood pooling.

[0206] The blanket can be operably connectable in use, e.g. with a wired or wireless connection to a readout device or patient monitor.

[0207] A plurality of antenna loops 12 can be used, distributed across the area of the blanket for measuring multiple locations at once without having to hold any device. The same single point attachment as shown and described above for the flexible cap 82 can also be used for this embodiment.

[0208] Embodiments of the present application thus provide an inductive sensor that can be used in almost any environment to detect the presence of bleeding. Advantages of the provided system include that it can be provided in a compact form factor, e.g. implemented as a handheld device, a blanket or a small cap, as discussed above. This means that it can easily be used in a pre-hospital or emergency triage setting. Furthermore, the results are instantaneous and easy to interpret. In particular, the data output signal of the inductive sensor system will immediately indicate any bleeding by means of a difference in reflected inductance. Thus, initial triage (e.g. for ICH or abdominal bleeding) can be performed anywhere and in a timely manner with low levels of operator expertise.

[0209] An example according to another aspect of the present application provides an inductive sensing method for detecting the presence of bleeding in one or more regions of a patient's body, the method being based on sensing an electromagnetic signal returned from the body in response to applying an electromagnetic excitation signal to the body.

[0210] Figure 11 A block diagram showing steps of an example method 100 according to one or more embodiments is shown.

[0211] The method comprises driving 102 at least one loop antenna of a resonator circuit with a drive signal so that it generates an electromagnetic excitation signal.

[0212] The method further comprises sensing 104 the return signal based on detecting a measure indicative of an additional inductance component added to the antenna of the resonator circuit by the return signal from the body, concurrently with the signal generation.

[0213] The method further comprises determining 106 the presence or absence of blood based on the detected measure of the additional inductance component.

[0214] The method further comprises generating 108 a data output indicative of the result of the determination.

[0215] The method can be used to detect the presence of blood in a cranial region. The method can be used to detect the presence of blood in an abdominal region. The method can further comprise determining, based on the blood detection, the occurrence of either an intracerebral hemorrhage or an abdominal hemorrhage.

[0216] For example, the method can comprise positioning at least one antenna of a resonator circuit for applying an electromagnetic excitation signal to a head region or an abdominal region, and receiving a return electromagnetic signal from the head region or the abdominal region.

[0217] As discussed above in relation to the system aspects of the invention, the determination of the presence or absence of blood accumulation can be based on a predefined threshold value associated with the presence of blood in at least one of the one or more regions of the body.

[0218] The threshold value can be a threshold value known to be associated with the presence of a hemorrhage in a cranial region or an abdominal region, as appropriate.

[0219] Implementation options and details for each of the above steps can be understood and interpreted in accordance with the explanations and descriptions provided above for the device aspects (i.e. system aspects) of the invention.

[0220] Any of the examples, options or embodiment features or details described above in relation to the device aspects (in relation to the inductive sensing system) of the invention can be applied or combined or incorporated in the present method aspects of the invention.

[0221] An example according to another aspect of the invention can provide a computer program product comprising code means configured, when executed on a processor, to cause the processor to be operatively coupled to:

[0222] a resonator circuit 10 comprising at least one loop antenna 12, and an electronic signal generator 14 coupled to the antenna for driving the antenna with a drive signal to cause it to generate an electromagnetic excitation signal, and

[0223] a signal sensing module 30 arranged for sensing the return signal based on detecting a measure indicative of an additional inductance component added to the antenna of the resonator circuit by the return signal from the body simultaneously with the signal generation, such that the processor performs an inductive sensing method according to any embodiment outlined above or described below or according to any claim of the present application.

[0224] As discussed above, some embodiments utilize a control module and / or microcontroller and / or microprocessor.

[0225] Any one or each of these components can be implemented in numerous ways, with software and / or hardware, to perform the various functions required. For example, a processor can be employed which employs one or more microprocessors that can be programmed using software (e.g., microcode) to perform the required functions. A control module may, however, be implemented with or without employing a processor, and also can be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmable microprocessors and associated circuitry) to perform other functions.

[0226] Examples of controller components that can be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0227] In various implementations, a processor or controller can be associated with one or more storage media such as volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM. The storage media can be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at required tasks. Various storage media can be fixed within a processor or controller or can be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller.

[0228] Variations to the disclosed embodiments can become apparent to those of ordinary skill in the art from the foregoing description and accompanying claims, which are presented by way of example only and are not intended to limit the scope of the application. In the claims, the word "comprising" does not exclude other elements or steps, and the words "a" or "an" do not exclude a plurality. A single processor or other unit can fulfil the functions of several items recited in the claims. If a measure is recited in mutually different dependent claims, this does not exclude that combinations of these measures can also be used. A computer program can be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state storage medium supplied together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. If the term "adapted to" is used in the claims and / or the specification it should be taken as equivalent to the term "configured to" in terms of the action of the claimant. Any reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

1. An inductive sensing system (8) arranged for sensing an electromagnetic signal returned from a body in response to the application of an electromagnetic excitation signal to the body, the system being adapted to detect the presence of bleeding in one or more areas of the body, the system comprising: The resonator circuit (10) includes at least two single-loop antennas (12a, 12b) and an electronic signal generator (14) coupled to the at least two single-loop antennas, the electronic signal generator being used to drive the at least two single-loop antennas with a driving signal so that the at least two single-loop antennas generate the electromagnetic excitation signal. as well as A signal sensing module (30) is arranged to sense the return signal from the body simultaneously with signal generation based on the detection of a metric indicating a corresponding additional inductive component, the additional inductive component being added by the return signal to each of the at least two single-loop antennas of the resonator circuit. The system is configured as follows: Determine the ratio between the measures of the additional inductance component detected and added to each of the at least two single-loop antennas (12a, 12b); The presence or absence of blood accumulation is determined based on the ratio of the determined additional inductance component; and Generate data output indicating the determined result.

2. The inductive sensing system according to claim 1, wherein, The presence or absence of blood pooling is determined based on a predefined threshold, which is associated with the presence of bleeding or blood pooling in at least one of the one or more regions of the body.

3. The inductive sensing system (8) according to any one of claims 1-2, wherein, The system is adapted to detect the presence of blood pooling in areas of the brain of the body.

4. The inductive sensing system (8) according to claim 3, wherein, The system is also configured to detect the occurrence of intracranial hemorrhage based on the blood test.

5. The inductive sensing system (8) according to any one of claims 1, 2 and 4, wherein, The system is adapted to detect the presence of blood pooling in the abdominal region of the body.

6. The inductive sensing system (8) according to claim 5, wherein, The system is also configured to detect the presence of abdominal bleeding based on the blood test.

7. The inductive sensing system (8) according to claim 3, wherein, The system can switch between at least two detection modes: In the first detection mode, the system is configured to detect the presence of blood pooling in a brain region of the body. as well as In the second detection mode, the system is configured to detect the presence of blood pooling in the abdominal region of the body.

8. The inductive sensing system (8) according to claim 5, wherein, The system can switch between at least two detection modes: In the first detection mode, the system is configured to detect the presence of blood pooling in a brain region of the body. as well as In the second detection mode, the system is configured to detect the presence of blood pooling in the abdominal region of the body.

9. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein the system is further configured to: The ratio is compared with a predefined threshold to determine the presence or absence of blood pooling.

10. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein, The at least two single-loop antennas are arranged concentrically with each other; The at least two single-loop antennas are mounted with an axial offset relative to each other, and / or The signal generator (14) is configured to drive the at least two single-loop antennas using drive signals with different corresponding AC frequencies.

11. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein, The system includes support structures (82, 92), and the at least two single-loop antennas (12a, 12b) are mounted in a fixed relationship with the support structures.

12. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein, The sensing system includes a handheld probe unit, which includes at least the resonator circuit (10).

13. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein, The system includes a headgear (82) to which at least two single-loop antennas (12a, 12b) are mounted, such that when the headgear is worn, the at least two single-loop antennas are held in a fixed relationship with the surface of the head.

14. The inductive sensing system (8) according to claim 13, wherein, The at least two single-loop antennas (12a, 12b) are mounted to the headgear at different locations so that they are held in different positions relative to the head when the headgear is worn.

15. The inductive sensing system (8) according to claim 13 or 14, wherein, The headgear (82) is formed of a flexible material so that it is held in place around the head when worn.

16. The inductive sensing system (8) according to any one of claims 1, 2, 4, 6, 7 and 8, wherein, The system includes clothing or sheets (92) for covering at least one area of ​​the body in one or more regions, and the at least two single-loop antennas (12a, 12b) are mounted to the clothing or sheets.

17. The inductive sensing system (8) according to claim 16, wherein, The at least two single-loop antennas are mounted on the clothing or bed sheet at different locations.

18. A computer program product including code units, which, when executed on a processor, cause the processor to perform an inductive sensing method (100) for detecting the presence of bleeding in one or more areas of a patient's body, the inductive sensing method being based on sensing an electromagnetic signal returned from the body in response to applying an electromagnetic excitation signal to the body, the inductive sensing method comprising: At least two single-loop antennas of the (102) resonator circuit are driven by a driving signal such that each single-loop antenna generates the electromagnetic excitation signal; Simultaneously with the signal generation, the return signal from the body is sensed (104) based on the detection of a metric indicating an additional inductive component, the additional inductive component being added by the return signal to each of the at least two single-loop antennas of the resonator circuit; Determine the ratio between the measures of the additional inductance component detected and added to each of the at least two single-loop antennas; The presence or absence of blood accumulation is determined based on the ratio of the determined additional inductance component, and Generate (108) data output indicating the determined result.

19. The computer program product according to claim 18, wherein, The inductive sensing method is used to detect the presence of blood in brain or abdominal regions.

20. The computer program product according to claim 19, wherein, The inductive sensing method also includes determining whether the bleeding is intracranial or abdominal based on blood detection.

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