@article{QIMS14204,
author = {Zhongshuai Zhang and Thomas Michaelis and Jens Frahm},
title = {Towards MRI temperature mapping in real time—the proton resonance frequency method with undersampled radial MRI and nonlinear inverse reconstruction},
journal = {Quantitative Imaging in Medicine and Surgery},
volume = {7},
number = {2},
year = {2017},
keywords = {},
abstract = {Optimal control of minimally invasive interventions by hyperthermia requires dynamic temperature mapping at high temporal resolution. Based on the temperature-dependent shift of the proton resonance frequency (PRF), this work developed a method for real-time MRI thermometry which relies on highly undersampled radial FLASH MRI sequences with iterative image reconstruction by regularized nonlinear inversion (NLINV). As a first step, the method was validated with use of a temperature phantom and ex vivo organs (swine kidney) subjected to heating by warm water or a pulsed laser source. The temperature maps obtained by real-time PRF MRI demonstrate good accuracy as independently controlled by fiber-optic temperature sensors. Moreover, the dynamic results demonstrate both excellent sensitivity to single laser pulses (20 ms duration, 6 J energy output) and high temporal resolution, i.e., 200 ms acquisition times per temperature map corresponding to a rate of 5 frames per second. In addition, future extensions to in vivo applications were prepared by addressing the breathing-related motion problem by a pre-recorded library of reference images representative of all respiratory states. In conclusion, the proposed method for real-time MRI thermometry now warrants further developments towards in vivo MRI monitoring of thermal interventions in animals.},
issn = {2223-4306}, url = {https://qims.amegroups.org/article/view/14204}
}