Methods and apparatus for ultrasound strain imaging

A system for providing ultrasonic strain imaging, comprising:

• an ultrasound probe for acquiring a sequence of RF frames during palpations of a target area;
• an external tracking device for measuring positions and orientations of said ultrasound probe at each said RF frame in said sequence of RF frames;
• a processor having a computer readable medium encoded with a program for optimizing the ultrasonic strain imaging, said program for sychronizing each of said positions and orientations of the ultrasound probe, the target area, or other instrument to a respective RF frame in said sequence of RF frames, automatically selecting multiple pairs of RF frames by minimizing a cost function which evaluates relative motion of any two image frames based upon the measured positions and orientations, calculating strain values for each of said selected multiple pairs of RF frames with the desired strain, and aligning and fusing images of the selected multiple pairs of RF frames with the desired strain from the approximately same location and orientation to generate a final strain image;
• and
• a display for displaying the final strain image.

A computer-readable medium comprising software, wherein, when executed by a computer, causes the computer to:

• receive a sequence of RF frames during palpations of a target area;
• receive positions and orientations of the ultrasound probe, the target area, or other instrument at each said RF frame in said sequence of said RF frames;
• synchronize each of the positions and orientations of the ultrasound probe, the target area or the other instrument to a respective RF frame in the sequence of RE frames;
• select multiple pairs of RF frames from an approximately same location and orientation from said synchronized sequence of RF frames by minimizing a cost function, said cost function evaluating the relative motion of any two image frames based upon the measured positions and orientations of said two image frames;
• select, from the automatically selected multiple pairs of RF frames, multiple pairs of RF frames with a desired strain;
• calculate strain values for each of said selected multiple pairs of RF frames with the desired strain;
• and
• align and fuse images of the selected multiple pairs of RF frames with the desired strain from the approximately same location and orientation to generate a final strain image.

A method of strain imaging, comprising:

• projecting a structured light pattern onto a surface of a target area to be imaged;
• acquiring a first set of images of the structured light pattern on the surface of the target area, said first set of images for reconstructing the surface of the target area;
• placing an ultrasound probe onto the target area;
• acquiring a second set of images including the surface of the target area and the ultrasound probe to determine the location of the probe;
• applying palpations to the target area;
• acquiring strain image data of the target area;
• constructing a finite element model based upon the first set of images, second set of images, and strain image data;
• and
• using the finite element model to solve for Young's Modulus to generate strain image.

A method for performing intraoperative calibration of an ultrasonic probe, comprising:

• projecting a structured light pattern onto a surface of the ultrasonic probe to generate a surface model of said ultrasonic probe, said ultrasonic probe for generating an ultrasound image;
• calibrating the surface model of the ultrasonic probe to the ultrasound image pre-operatively;
• attaching a sensor to the surface of the ultrasonic probe at a sensor location;
• determining a transformation between the surface model of the ultrasonic probe and the sensor at the sensor location;
• and
• computing a probe calibration matrix based upon the pre-operative calibration of the surface model of the ultrasonic probe to the ultrasound image and the transformation between the surface model of the probe and the sensor.