Image registration and principal component analysis based multi-baseline phase correction method for proton resonance frequency thermometry
Inventors
Majeed, Waqas • Bhat, Himanshu • Schneider, Rainer • Campbell, Adrienne
Assignees
Siemens Healthineers AG • US Department of Health and Human Services
Publication Number
US-11301997-B2
Publication Date
2022-04-12
Expiration Date
2040-04-15
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Abstract
A method for phase correction in proton resonance frequency (PRF) thermometry application includes acquiring a series of magnetic resonance (MR) images comprising a first MR image and plurality of subsequent MR images depicting an anatomical area of interest. The MR images are acquired while tissue in the anatomical area of interest is undergoing a temperature change. Each subsequent MR image is registered to the first MR image to yield a plurality of registered images. A plurality of basis images are computed from the registered images using Principal Component Analysis (PCA). The basis images are used to remove motion-related phase changes from a second series of MR images, thereby yielding a motion corrected second series of MR images. One or more temperature difference maps are generated that depict a relative temperature change for the tissue in the anatomical area of interest based on the motion corrected second series.
Core Innovation
The invention relates to a multi-baseline phase correction method for proton resonance frequency (PRF) thermometry that combines registration-based motion correction with principal component analysis (PCA) to improve accuracy in thermal therapy procedures. The method involves acquiring a series of magnetic resonance (MR) images of an anatomical area undergoing temperature change, registering subsequent images to a first baseline image, and computing basis images from the registered set using PCA. These basis images are then used to remove motion-related phase changes from a second series of MR images, thus yielding a motion corrected series which is used to generate temperature difference maps depicting relative temperature changes in the tissue.
The problem addressed by this invention is the inaccuracy in PRF thermometry caused by motion-related changes in the main magnetic field (B0), which affect phase difference measurements even after image registration-based motion correction. Such inaccuracies limit the clinical effectiveness of PRF thermometry in monitoring thermal therapy, particularly in moving organs. The invention seeks to overcome this by integrating PCA-based multi-baseline phase correction with registration to better correct for motion-induced phase variations.
The inventive approach provides an advancement over conventional single or dictionary-based baseline methods for phase correction by enabling interpolation of motion states not directly represented among baseline images, and by reducing noise through PCA's dimensionality reduction. This results in significant reduction in bias and variance in temperature difference estimates, demonstrated using in-vivo human brain and cardiac datasets. The method can be implemented offline or adapted for real-time thermometry, employing various MRI sequences and supporting clinical use in thermal therapy procedures.
Claims Coverage
The patent discloses three independent claims covering a method, a system, and an article of manufacture for phase correction in PRF thermometry applications. The main inventive features involve the use of principal component analysis combined with image registration to correct motion-related phase changes in MR images for improved temperature mapping.
Method for phase correction in PRF thermometry using PCA and image registration
This method acquires a series of MR images of an anatomical area undergoing temperature change, registers each subsequent image to the first image to yield registered images, computes basis images from these using Principal Component Analysis (PCA), uses these basis images to remove motion-related phase changes from a second series of MR images, and generates temperature difference maps based on the motion corrected images.
System for phase correction in PRF thermometry with RF coils, computing capability, and display
The system includes RF coils configured to acquire MR images depicting anatomical areas with temperature change, computers connected to the coils that perform image registration to a first image, compute basis images using PCA from the registered images, remove motion-related phase changes from a second MR image series using the basis images, and generate temperature difference maps for display interpreting relative temperature changes.
Article of manufacture embodying computer-executable instructions for phase correction method
A non-transitory computer-readable medium containing instructions to perform the method comprising receiving MR image series, registering subsequent images to a first baseline image, computing basis images via PCA, removing motion-related phase changes from a second MR image series using the basis images, and generating temperature difference maps representing relative temperature changes for an anatomical area undergoing temperature change.
The claims collectively cover the innovative use of PCA-generated basis images combined with registration-based motion correction to improve accuracy of temperature difference mapping in PRF thermometry applications, addressing motion-related phase artifacts in MR images of tissue undergoing temperature changes.
Stated Advantages
Major reduction in the standard deviation of temperature difference estimates compared with conventional averaged baseline and dictionary-based methods.
Significantly smaller bias in temperature estimates in regions prone to susceptibility-related B0 changes.
Ability to interpolate motion states between those captured by baseline images, improving representation of complex motion.
Reduced noise in correction due to PCA dimensionality reduction pushing incoherent noise into less significant basis images.
Potential to increase the accuracy of PRF thermometry in or near moving organs, resulting in improved clinical outcomes.
Documented Applications
Use with thermal therapy procedures such as High Intensity Focused Ultrasound (HIFU) and laser based heating to monitor tissue temperature in real time.
Application to PRF thermometry in moving organs including human brain and heart.
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