Improved MRI techniques for measurement of absolute temperature distributions

描述（由申请人提供）：本研究项目的目标是开发和实施一种基于MRI的技术，该技术可创建对热治疗程序至关重要的组织的准确、实时温度图。 这项研究是使热疗法在临床上可行的重要组成部分。为了使热治疗程序安全、有效和省时，必须在整个治疗过程中监测感兴趣区域中的组织的温度变化。该研究项目的目标是开发和实施3D磁共振成像（MRI）温度测量技术，以创建准确，可靠，实时的温度图，可用于监测热治疗过程中的组织加热。为了实现这一目标，研究将集中在三个领域：1）开发改进的温度测量技术，并证明它们能够测量组织中的温度分布; 2）减少由于运动引起的温度测量误差; 3）研究提高采集速度的技术。1)目前正在研究三个脉冲序列作为可能的选项，用于结合，或作为替代，广泛流行的，但容易出错，质子共振频移（PRFS）技术。一个化学位移光谱脉冲序列和两个3D单发扩散加权脉冲序列目前都在运行。它们的成像参数将针对温度测量进行优化，并将在体外和体内组织样本的加热实验中进行测试。2)光谱脉冲序列的自参考能力可以潜在地用于减少来自运动的误差。在离体和体内组织研究中，我们将测试光谱序列使用脂肪信号减少运动诱导的磁化率误差和运动诱导的配准误差的能力。3)两种技术将被调查，以提高扫描的时间分辨率。并行成像沿着重建算法（如GRAPPA）的使用可应用于任何脉冲序列，以减少扫描时间。时间约束重建算法已被证明能够减少扫描时间，并且也可以用任何脉冲序列来实现。

DESCRIPTION (provided by applicant): The goal of this research project is to develop and implement an MRI-based technique that creates accurate, real-time temperature maps of tissue that are vital to thermal therapy procedures. This research is a vital part of making thermal therapies clinically viable. For thermal therapy procedures to be safe, effective and time-efficient, the tissue in the region of interest must be monitored for temperature changes throughout the treatment. The goal of this research project is to develop and implement 3D magnetic resonance imaging (MRI) temperature measurement techniques to create accurate, robust, real-time temperature maps that can be used to monitor tissue heating during thermal therapy treatments. To achieve this goal, the research will focus on three areas: 1) develop improved temperature measurement techniques and demonstrate they are capable of measuring temperature distributions in tissue; 2) reduce temperature measurement errors that are due to motion; 3) investigate techniques to increase acquisition speed. 1) Three pulse sequences are currently being investigated as possible options to be used in conjunction with, or as an alternative to, the widely popular, but error prone, proton resonance frequency shift (PRFS) technique. A chemical shift spectroscopy pulse sequence, and two 3D single-shot diffusion weighted pulse sequence are all currently operational. Their imaging parameters will be optimized for temperature measurement and they will be tested in heating experiments on ex vivo and in vivo tissue samples. 2) The self referencing capability of the spectroscopic pulse sequence can potentially be used to reduce errors from motion. In ex vivo and in vivo tissue studies, we will test the ability of the spectroscopic sequence to use the fat signal to reduce both motion induced susceptibility errors and motion induced registration errors. 3) Two techniques will be investigated for improving the temporal resolution of the scans. The use of parallel imaging along with reconstruction algorithms such as GRAPPA can be applied to any pulse sequence to decrease the scan time. A temporally constrained reconstruction algorithm has been shown to be capable of reducing scan time and can also be implemented with any pulse sequence.