Systems and methods for motion compensation in ultrasonic respiration monitoring

A respiration detection system comprising:

• a first probe (102) comprising:
• an ultrasonic transducer (112) stationary located within the first probe and having a transceiving face (113) oriented at an acute angle (Ω) relative to a front plane (114) of the first probe (102), wherein the ultrasonic transducer (112) is configured to produce an ultrasound beam (143) at the transceiving face (113) for transmission into an internal structure inside the body of a patient, wherein the internal structure is one of a liver (144), spleen, or kidney of the patient,
• a first accelerometer unit (121), and
• a first magnetic field unit (122), wherein the ultrasonic transducer (112), the first accelerometer unit (121), and the first magnetic field unit (122) are stationary located in the first probe (102);
• and
• a second probe (104) comprising:
• a second accelerometer unit (128), and
• a second magnetic field unit (129), wherein the second accelerometer unit (128) and the second magnetic field unit (129) are stationary located in the second probe (104);
• wherein the ultrasonic transducer (112), the first and second accelerometer units (121;
• 128), and the first and second magnetic field units (122;
• 129) are coupled to a signal processor (134),
• wherein the first probe (102) is configured to be placed on a front side (103) of the body (101) of the patient,
• wherein the second probe (104) is configured to be placed on a dorsal side (105) of the body (101),
• wherein signals from the first accelerometer unit (121) indicate first spatial orientations of the first probe (102) with the ultrasound transducer (112) and the first magnetic field unit (122) therein,
• wherein signals from the second accelerometer unit (128) indicate second spatial orientations of the second probe (104) with the second magnetic field unit (129) therein,
• wherein the first and second spatial orientations are relative to a fixed coordinate frame,
• wherein signals from the first magnetic field unit (122) in interaction with the second magnetic field unit (129) and orientations of the magnetic field units (122;
• 129) as provided by signals from the first and second accelerometer units (121;
• 128) are inputs to the signal processor (134) to calculate variable spatial distance between the first and second probes (102;
• 104) and thereby calculate spatial movement and orientation of the ultrasonic transducer (112) as induced by respiration of the patient,
• wherein a first one of the first magnetic field unit (122) and the second magnetic field unit (129) comprises a magnetic field sensor device, and wherein the other one of the first magnetic field unit (122) and the second magnetic field unit (129) comprises an electromagnet device configured to generate a magnetic field to be detected by the magnetic field sensor device, and wherein the magnetic field is related to distance between the first and second probes (102;
• 104), and
• wherein the signal processor (134) is configured to calculate, based on inputs from the first and second accelerometer units (121;
• 128) and from the first magnetic field unit (122) interacting with the second magnetic field unit (129), movement and orientation of the ultrasonic transducer (112) in the first probe (102) in relation to an expected direction of motion of the internal structure (144) inside the body of the patient relative to a longitudinal axis of the patient, the movement and orientation of the ultrasonic transducer (112) being related to respiration parameters associated with the respiratory muscles of the patient.

A respiration detection system comprising:

• a first probe (102) comprising:
• an ultrasonic transducer (112) stationary located within the first probe and having a transceiving face (113) oriented at an acute angle (Ω) relative to a front plane (114) of the first probe (102), wherein the ultrasonic transducer (112) is configured to produce an ultrasound beam (143) at the transceiving face (113) for transmission into an internal structure inside the body of a patient, wherein the internal structure is one of a liver (144), spleen, or kidney of the patient,
• a first accelerometer unit (121), and
• a first magnetic field unit (122), wherein the ultrasonic transducer (112), the first accelerometer unit (121), and the first magnetic field unit (122) are stationary located in the first probe (102);
• and
• a second probe (104) comprising:
• a second accelerometer unit (128), and
• a second magnetic field unit (129), wherein the second accelerometer unit (128) and the second magnetic field unit (129) are stationary located in the second probe (104);
• wherein the ultrasonic transducer (112), the first and second accelerometer units (121;
• 128), and the first and second magnetic field units (122;
• 129) are coupled to a signal processor (134),
• wherein the first probe (102) is configured to be placed on a front side (103) of the body (101) of the patient,
• wherein the second probe (104) is configured to be placed on a dorsal side (105) of the body (101),
• wherein signals from the first accelerometer unit (121) indicate first spatial orientations of the first probe (102) with the ultrasound transducer (112) and the first magnetic field unit (122) therein,
• wherein signals from the second accelerometer unit (128) indicate second spatial orientations of the second probe (104) with the second magnetic field unit (129) therein,
• wherein the first and second spatial orientations are relative to a fixed coordinate frame,
• wherein signals from the first magnetic field unit (122) in interaction with the second magnetic field unit (129) and orientations of the magnetic field units (122;
• 129) as provided by signals from the first and second accelerometer units (121;
• 128) are inputs to the signal processor (134) to calculate variable spatial distance between the first and second probes (102;
• 104) and thereby calculate spatial movement and orientation of the ultrasonic transducer (112) as induced by respiration of the patient,
• wherein the first probe (102) is configured to be placed on the patient's body to direct the ultrasound beam towards the internal structure inside the patient's body and receive ultrasonic echo signals from the internal structure,
• the first probe (102) further comprising a housing (110) with a cavity (111),
• the ultrasonic transducer (112) being located in the cavity (111), a transceiving face (113) of the ultrasonic transducer (112) being at an acute angle (Ω) relative to the front plane (114) of the housing at or adjacent a cavity mouth of the cavity (111) of the housing (110),
• wherein the ultrasonic transducer (112) is fixedly located in the cavity (111) of the housing (110) by way of an open-ended socket-like member (120) of ultrasound non-sonolucent material which provides a recess that extends from the transceiving face (113) towards the front plane (114),
• wherein a first body part (117) of an ultrasound sonolucent material is located in the socket-like member (120) at and in front of the transceiving face (113) of the ultrasonic transducer (112) towards the front plane (114),
• wherein the first accelerometer unit (121) and the first magnetic field detection unit (122) are connected to a printed circuit board (119) within the cavity (111) of the housing (110),
• wherein a front surface of the first probe (102) exhibits at least one of an inherent tacky property, an attachment face for an adhesive member or a double-sided tacky tape, or an engagement face for a tacky body layer,
• wherein the ultrasonic transducer (112) is configured to connect to a transceiver section of the signal processor (134),
• wherein the ultrasonic transducer (112) is mounted at a bottom region of the open-ended socket-like member (120), and
• wherein the ultrasonic transducer (112) and the open-ended socket-like member (120) extend from the printed circuit board (119).

A system for motion compensation in ultrasound-based detection of respiration parameters of a human, the system comprising:

• a first probe (102) configured to be attached to a front body surface (103) of the human, the first probe (102) having an ultrasound transducer (112), a first accelerometer unit (121), and a first magnetic field unit (122);
• a second probe (104) configured to be attached to a dorsal body surface (105) of the human, the second probe (104) having a second accelerometer unit (122), and a second magnetic field unit (129);
• and
• a signal processor (134) coupled to the ultrasonic transducer (112), the first and second accelerometer units (121;
• 128), and the first and second magnetic field units (122;
• 129);
• wherein the ultrasound transducer (112) in the first probe (102)7 is configured to transmit an ultrasound beam into an internal structure (144) inside the body of the human and receive ultrasound echo signals from the internal structure;
• wherein the second magnetic field unit (129) is configured to generate a magnetic field transmitted to and detected by the first magnetic field unit (122);
• and
• wherein the signal processor is configured to:
• calculate an orientation of the first accelerometer unit (121) relative to a fixed coordinate frame using derived parameters from the first accelerometer unit (121), and further calculating the derived parameters as unit vectors representing an orientation of the ultrasound beam and an orientation of the first magnetic field unit (122);
• calculate an orientation of the second accelerometer unit (128) relative to the fixed coordinate frame using further derived parameters, and calculating the further derived parameters including body back support tilt angle (a) and unit vectors representative of a spatial direction from the second magnetic field unit (129) to the first magnetic field unit (122), an orientation of the second magnetic field unit (129), and an expected direction of motion of the internal structure relative to a longitudinal axis of a torso of the human during exhalation;
• calculate any varying distance between the first and second magnetic field units (122;
• 129) based on the detection of the magnetic field;
• and
• process results from the calculated orientations of the first and second accelerometer units (121;
• 128), and further derived parameters from the first and second accelerometer units (121;
• 128), and the varying distance measured by the first and second magnetic field units (122;
• 129) to generate correction parameters to compensate for measurement errors in the received ultrasound echo signals caused by motion of the ultrasound transducer (112).