Ultrasonic apparatus for measuring a labor progress parameter

An apparatus (10) for measuring a labor progress parameter during childbirth by ultrasound images obtained by ultrasonic pulses, said apparatus (10) comprising:

• an ultrasound probe;
• a fastening means for fastening said ultrasound probe (1) onto the body of a parturient (2) so that said probe (1) has a visual field (7) that includes a portion of the body of said parturient (2) and of a foetus (3), in particular the endocervical canal (8) or the pubis of said parturient (2);
• a control unit (13) for receiving and analysing signals from said ultrasound probe (1), said control unit (13) creating or receiving as input by said probe a reference ultrasound image (11) and a plurality of subsequent ultrasound images (12), which are taken in succession after said reference ultrasound image (11);
• a user interface (14) for selecting a region of interest (21) in said reference ultrasound image (11) by an operator, said user interface (14) adapted to select said region of interest (21) substantially centred about said portion of the parturient's body, said region of interest (21) comprising a plurality of pixels (23);
• wherein said control unit (13) comprises:
• an automatic tracking means for tracking said region of interest (21), said automatic tracking means adapted to identify derived regions of interest (22) in selected images of said plurality of subsequent ultrasound images (12), said derived regions of interest (22) deriving from said region of interest (21) that is selected in said reference ultrasound image (11), said tracking means comprising:
• a means for calculating a predetermined local pixel function for each pixel (23) or group of pixels of said region of interest (21) in said reference ultrasound image (11) and in each selected image of said plurality of subsequent ultrasound images (12),
• a means for iteratively calculating, starting from said reference ultrasound image (11), the position of said derived region of interest (22) in each selected image, said means for iteratively calculating adapted to perform comparisons between:
• values of said local pixel function calculated at the pixels (23) of said region of interest (21) of an image of the selected images;
• values of said local pixel function calculated at pixels of said region of interest (22) of a subsequent ultrasound image (12);
• a means for comparing each position of said derived region of interest (22) with the position of said region of interest (21) in said reference ultrasound image (11) or in another image of said selected images and for calculating a labor progress parameter.