HYBRID PRF-THERMOMETRY IN THE MYOCARDIUM

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 目的：近年来，人们越来越关注在低血压下进行心脏介入治疗，如电生理消融术。 MR引导。在这些程序中直接监测温升可能有助于验证 成功消融和预测治疗结果。在这里，我们调查监测温度变化的可行性 在左心室心肌的实时。基于质子共振频率（PRF）偏移的温度图像 使用结合多基线减法和无参考测温的混合方法重建。 材料和方法：在三名志愿者（未加热）中采集短轴自由呼吸心脏图像， 在3 T扫描仪上使用4-5个交错的螺旋梯度回波采集进行实时采集，回波时间为3 ms、5 ms，以及 七小姐。 在Matlab中离线实现了混合温度图像重建。混合成像模型假设三个 在热治疗期间，源对图像相位有贡献：背景解剖相位、空间平滑相位 偏差和聚焦的热诱导相移。 对于处理的无参考部分，使用六阶背景多项式，并且多基线 库由150个在自由呼吸期间采集的图像（滑动窗口重建）组成，代表 大约三个心动周期。在感兴趣的圆形区域上进行温度重建， 整个左心室测量图像中间隔和游离室壁的温度不确定度 在心脏收缩期和心脏舒张期。 要了解卢卡斯中心正在进行的其他项目，请访问http://rsl.stanford.edu/ （卢卡斯年度报告和 ISMRM 2011摘要）

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Objective: In recent years there has been increased interest to perform cardiac interventions such as EP ablation under MR-guidance. Directly monitoring the temperature rise during these procedures could potentially be helpful to verify successful ablation and predict treatment outcome. Here, we investigate the feasibility of monitoring temperature changes in the left ventricular myocardium in real-time. Temperature images based on the proton resonance frequency (PRF) shift are reconstructed using a hybrid method that combines multi-baseline subtraction and referenceless thermometry. Materials and Methods: Short-axis free-breathing cardiac images were acquired in three volunteers (no heat applied) in real-time using spiral gradient echo acquisitions with 4-5 interleaves on a 3T scanner using echo times of 3 ms, 5 ms, and 7 ms. Hybrid temperature image reconstruction was performed off-line in Matlab. The hybrid imaging model assumes that three sources contribute to image phase during thermal treatment: Background anatomical phase, spatially smooth phase deviations, and focal, heat-induced phase shifts. For the referenceless portion of the processing, sixth-order background polynomials were used and the multi-baseline libraries were comprised of 150 images (sliding window reconstruction) acquired during free breathing, representing approximately three cardiac cycles. Temperature reconstruction was performed over circular regions of interest containing the entire left ventricle. Temperature uncertainty was measured in the septum and the free ventricular wall in images during systole and diastole. To read about other projects ongoing at the Lucas Center, please visit http://rsl.stanford.edu/ (Lucas Annual Report and ISMRM 2011 Abstracts)