Accelerated MR thermometry using the Kalman filter

Li Zhao,Craig Meyer,Samuel Fielden,Xue Feng,Wilson Miller,Kim Butts Pauly,Max Wintermark

doi:10.1186/2050-5736-3-s1-p40

Abstract

Magnetic resonance (MR) imaging plays an important role in monitoring thermal treatment. It can quantify thermal dose with temperature maps based on the proton-resonance frequency shift. Volumetric coverage is desirable, but acquiring multiple slices imaging is time consuming. Therefore, accelerated methods are needed to improve the spatial and temporal resolution in MR thermometry. Multi-channel coils are not widely available for MR-guided FUS systems, so conventional parallel imaging methods cannot be used for acceleration. Compressed sensing methods show promise, but the computation is currently too slow to provide real-time feedback. The Kalman filter is an optimal estimation method that has been widely used for real-time tracking in other fields. It has been studied for filtering of temperature for FUS. Here we apply it to accelerate image acquisition for thermometry.

Highlights

Background/introduction Magnetic resonance (MR) imaging plays an important role in monitoring thermal treatment
The Kalman filter (KF) uses prior state information to predict the current state with a dynamic system model: x(k) = x(k-1) + w(k-1) z(k) = U(k) F x(k) + v(k) x(k) is the target image at the kth frame and the first function describes the state transition. z(k) is the corresponding acquired data
F is a Fourier transform operator and U(k) is an undersampling pattern. w and v are the system and measurement noise, assumed to have white Gaussian distributions with covariance matrices estimated by the KF. w models state changes resulting from heating

Summary

Introduction

Background/introduction Magnetic resonance (MR) imaging plays an important role in monitoring thermal treatment. Accelerated MR thermometry using the Kalman filter Volumetric coverage is desirable, but acquiring multiple slices imaging is time consuming. Accelerated methods are needed to improve the spatial and temporal resolution in MR thermometry. Multi-channel coils are not widely available for MR-guided FUS systems, so conventional parallel imaging methods cannot be used for acceleration.

Results

Conclusion