System and method for fusing real-time ultrasound images with pre-acquired medical images
Inventors
Kruecker, Jochen • Xu, Sheng • Glossop, Neil David • Choyke, Peter Lyle • Wood, Bradford J.
Assignees
Koninklijke Philips NV • Government of the United States of America
Publication Number
US-8731264-B2
Publication Date
2014-05-20
Expiration Date
2027-11-26
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Abstract
A method, apparatus and system for fusing real-time ultrasound images with pre-acquired medical images are described.
Core Innovation
The invention describes a method, apparatus, and system for fusing real-time ultrasound (US) images with pre-acquired medical images from different modalities, such as magnetic resonance (MR), computer tomographic (CT), positron emission spectroscopic (PET), or single photon emission computed tomographic (SPECT) imaging. The solution involves transforming the coordinate system of the ultrasound image to that of the US sensor, then to a tracking system coordinate, and finally to the coordinate system of the pre-acquired image. This fusion allows for real-time imaging combined with higher resolution images from other modalities.
The problem being addressed arises because different medical imaging modalities have their own benefits and drawbacks. For example, MR imaging offers excellent resolution and detail but complicates and prolongs invasive procedures like biopsies, leading to higher patient costs. Ultrasound imaging, while providing fast, real-time images facilitating in-situ testing, lacks sufficient resolution for certain applications. Therefore, there is a need for a method and system that combines the real-time speed of ultrasound with the detailed resolution of pre-acquired images from other modalities to improve accuracy and efficiency in medical testing and treatment.
The invention provides a registration technique whereby a point cloud selected in the tracked ultrasound image is matched to a surface segmentation of the pre-acquired image using an iterative closest point (ICP) algorithm or alternatively manual or automatic image registration methods. This registration enables displaying the fused images in a common coordinate system, thereby allowing precise real-time guidance during medical procedures, such as biopsies or therapeutic interventions, without relying on fiducial markers. The system maintains flexible, freehand use of the ultrasound probe while integrating high-resolution imagery.
Claims Coverage
The patent contains two independent claims covering both a method and an apparatus for fusing real-time ultrasound images with pre-acquired images of another modality. The claims focus on coordinate transformations, point cloud matching, registration, and image display.
Method for fusing images using coordinate transformations and registration
Obtaining a real-time ultrasound (US) image including a test location from a segmented pre-acquired image of another modality; manually or automatically selecting a point cloud in the US image; transforming the US image coordinates to a coordinate system of a tracking system; transforming from the tracking system coordinates to the pre-acquired image coordinates; matching the point cloud to a surface segmentation of the pre-acquired image; registering the real-time US with the pre-acquired image; and displaying both images in the coordinate system of the pre-acquired image.
Apparatus for performing image fusion with tracking and registration
An apparatus including a US device to obtain real-time US images, a tracking system to determine the US device position relative to its coordinate system, and a programmed computer to select the point cloud, perform coordinate transformations from US image to tracking system then to pre-acquired image, match the point cloud to segmented pre-acquired image surfaces, register the images, and display the fused images. The apparatus may include repeatedly generated US images, possibly three-dimensional, and a medical device guided by the fused images for sampling or therapy at target regions.
The claims cover a comprehensive process and system for integrating real-time ultrasound imaging with pre-acquired segmented images from other modalities through coordinate transformations, point cloud matching using algorithms like ICP, registration, and coordinated displays. The invention enables accurate and efficient medical imaging fusion without reliance on fiducials and supports use during medical procedures.
Stated Advantages
Enables rapid registration of real-time freehand ultrasound images with high-resolution pre-acquired images during normal ultrasound examination without prolonging patient discomfort.
Avoids reliance on fiducial markers, allowing flexible and freehand use of the ultrasound probe.
Combines the benefits of high resolution from pre-acquired images with the speed and flexibility of real-time ultrasound.
Improves accuracy of testing and therapy by spatially correlating real-time and pre-acquired images in a common coordinate system.
Documented Applications
Guiding needle positioning for biopsies or seed placement using a real-time freehand transrectal ultrasound (TRUS) probe fused with pre-acquired images.
Performing medical procedures including tests and therapeutic interventions at target locations displayed via fused real-time ultrasound and pre-acquired images.
Intra-procedural imaging where pre-acquired images are used to select regions of interest for real-time ultrasound analysis.
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