System and method for 3-D medical imaging using 2-D scan data
First Claim
1. A method for generating a three-dimensional representation of a region of tissue scanned by a transducer, comprising the following steps:
- A) pre-determining a calibrated speckle correlation-versus-distance function for the transducer to be used, for the tissue to be scanned, or both;
B) generating a series of 2-D image frames, divided into image elements;
C) identifying image elements representing speckle;
D) for each scanned image frame, estimating actual speckle correlation with at least one other frame based on at least the image elements in corresponding portions of the respective frames;
E) estimating the distance between pairs of image frames by evaluating the correlation-versus-distance function with the corresponding estimated actual speckle correlation for the pairs of frames, including estimating the distance between a reference and at least one other image frame;
F) for each frame for which correlation has been estimated, determining its relative displacement from the reference by evaluating the correlation-versus-distance function with the estimated actual speckle correlation;
G) registering the different frames in a three-dimensional format as a 3-D representation; and
H) displaying the 3-D representation.
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Accused Products
Abstract
A region of tissue is scanned as a series of 2-D frames. The correlation of substantially homogeneous speckle regions in the frames is determined and is compared with a precalibrated speckle correlation-versus-distance function to give an estimate of the distance between the frames. In some applications, the frames are partitioned into sub-frames, whose correlation values and distances are combined according to predetermined functions to give a distance estimate between the frames as a whole. The reliability of the distance estimates is improved and evaluated in various ways, for example, by comparing combinations of possible distances from end frames via intermediate frames, and by comparing computed frame or sub-frame velocities with a known or estimated transducer velocity. Once the relative distances of the 2-D frames are estimated, a 3-D image is compiled using registration techniques. Image frames need not be parallel.
256 Citations
16 Claims
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1. A method for generating a three-dimensional representation of a region of tissue scanned by a transducer, comprising the following steps:
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A) pre-determining a calibrated speckle correlation-versus-distance function for the transducer to be used, for the tissue to be scanned, or both; B) generating a series of 2-D image frames, divided into image elements; C) identifying image elements representing speckle; D) for each scanned image frame, estimating actual speckle correlation with at least one other frame based on at least the image elements in corresponding portions of the respective frames; E) estimating the distance between pairs of image frames by evaluating the correlation-versus-distance function with the corresponding estimated actual speckle correlation for the pairs of frames, including estimating the distance between a reference and at least one other image frame; F) for each frame for which correlation has been estimated, determining its relative displacement from the reference by evaluating the correlation-versus-distance function with the estimated actual speckle correlation; G) registering the different frames in a three-dimensional format as a 3-D representation; and H) displaying the 3-D representation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for generating a three-dimensional representation of a region of tissue including:
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A) an ultrasonic transducer scanning the region as a series of 2-D image frames, each frame comprising a pattern of image elements; B) processing means; 1) for identifying in each 2-D image frame image elements representing speckle; 2) for each scanned image frame, for estimating actual speckle correlation with at least one other frame based on at least the image elements in corresponding portions of the respective frames; 3) for estimating the distance between pairs of image frames by evaluating a predetermined calibrated correlation-versus-distance function with the corresponding estimated actual speckle correlation for the pairs of frames, including estimating the distance between a reference and at least one other image frame; 4) for each frame for which correlation has been estimated, for determining its relative displacement from the reference by evaluating the correlation-versus-distance function with the estimated actual speckle correlation; and 5) for registering the different frames in a three-dimensional format as a 3-D representation; C) a memory including a 2-D frame data portion for storing the 2-D image frames and a correlation data portion for storing predetermined parameters of the correlation-versus-distance function; and D) a display means for displaying the 3-D representation.
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Specification