PDF(Pubmed)
Abstract：
BACKGROUND: Interventional magnetic resonance imaging (MRI) can provide a comprehensive setting for microwave ablation of tumors with real-time monitoring of the energy delivery using MRI-based temperature mapping. The purpose of this study was to quantify the accuracy of three-dimensional (3D) real-time MRI temperature mapping during microwave heating in vitro by comparing MRI thermometry data to reference data measured by fiber-optical thermometry.
METHODS: Nine phantom experiments were evaluated in agar-based gel phantoms using an in-room MR-conditional microwave system and MRI thermometry. MRI measurements were performed for 700 s (25 slices; temporal resolution 2 s). The temperature was monitored with two fiber-optical temperature sensors approximately 5 mm and 10 mm distant from the microwave antenna. Temperature curves of the sensors were compared to MRI temperature data of single-voxel regions of interest (ROIs) at the sensor tips; the accuracy of MRI thermometry was assessed as the root-mean-squared (RMS)-averaged temperature difference. Eighteen neighboring voxels around the original ROI were also evaluated and the voxel with the smallest temperature difference was additionally selected for further evaluation.
RESULTS: The maximum temperature changes measured by the fiber-optical sensors ranged from 7.3 K to 50.7 K. The median RMS-averaged temperature differences in the originally selected voxels ranged from 1.4 K to 3.4 K. When evaluating the minimum-difference voxel from the neighborhood, the temperature differences ranged from 0.5 K to 0.9 K. The microwave antenna and the MRI-conditional in-room microwave generator did not induce relevant radiofrequency artifacts.
CONCLUSIONS: Accurate 3D real-time MRI temperature mapping during microwave heating with very low RMS-averaged temperature errors below 1 K is feasible in gel phantoms.
CONCLUSIONS: Accurate MRI-based volumetric real-time monitoring of temperature distribution and thermal dose is highly relevant in clinical MRI-based interventions and can be expected to improve local tumor control, as well as procedural safety by extending the limits of thermal (e.g., microwave) ablation of tumors in the liver and in other organs.
CONCLUSIONS: Interventional MRI can provide a comprehensive setting for the microwave ablation of tumors. MRI can monitor the microwave ablation using real-time MRI-based temperature mapping. 3D real-time MRI temperature mapping during microwave heating is feasible. Measured temperature errors were below 1 °C in gel phantoms. The active in-room microwave generator did not induce any relevant radiofrequency artifacts.
METHODS: Nine phantom experiments were evaluated in agar-based gel phantoms using an in-room MR-conditional microwave system and MRI thermometry. MRI measurements were performed for 700 s (25 slices; temporal resolution 2 s). The temperature was monitored with two fiber-optical temperature sensors approximately 5 mm and 10 mm distant from the microwave antenna. Temperature curves of the sensors were compared to MRI temperature data of single-voxel regions of interest (ROIs) at the sensor tips; the accuracy of MRI thermometry was assessed as the root-mean-squared (RMS)-averaged temperature difference. Eighteen neighboring voxels around the original ROI were also evaluated and the voxel with the smallest temperature difference was additionally selected for further evaluation.
RESULTS: The maximum temperature changes measured by the fiber-optical sensors ranged from 7.3 K to 50.7 K. The median RMS-averaged temperature differences in the originally selected voxels ranged from 1.4 K to 3.4 K. When evaluating the minimum-difference voxel from the neighborhood, the temperature differences ranged from 0.5 K to 0.9 K. The microwave antenna and the MRI-conditional in-room microwave generator did not induce relevant radiofrequency artifacts.
CONCLUSIONS: Accurate 3D real-time MRI temperature mapping during microwave heating with very low RMS-averaged temperature errors below 1 K is feasible in gel phantoms.
CONCLUSIONS: Accurate MRI-based volumetric real-time monitoring of temperature distribution and thermal dose is highly relevant in clinical MRI-based interventions and can be expected to improve local tumor control, as well as procedural safety by extending the limits of thermal (e.g., microwave) ablation of tumors in the liver and in other organs.
CONCLUSIONS: Interventional MRI can provide a comprehensive setting for the microwave ablation of tumors. MRI can monitor the microwave ablation using real-time MRI-based temperature mapping. 3D real-time MRI temperature mapping during microwave heating is feasible. Measured temperature errors were below 1 °C in gel phantoms. The active in-room microwave generator did not induce any relevant radiofrequency artifacts.
摘要：
背景：介入性磁共振成像（MRI）可以为肿瘤的微波消融提供全面的环境，并使用基于MRI的温度映射实时监测能量输送。这项研究的目的是通过将MRI测温数据与光纤测温仪测量的参考数据进行比较，来量化体外微波加热过程中三维（3D）实时MRI温度映射的准确性。
方法：使用室内MR条件微波系统和MRI测温法在基于琼脂的凝胶体模中评估了九个体模实验。MRI测量进行700s（25片；时间分辨率2s）。用两个距离微波天线约5mm和10mm的光纤温度传感器监测温度。将传感器的温度曲线与传感器尖端处的感兴趣的单体素区域（ROI）的MRI温度数据进行比较；MRI测温的准确性被评估为均方根（RMS）平均温度差。还评估了原始ROI周围的18个相邻体素,并且另外选择具有最小温度差的体素用于进一步评估。
结果：光纤传感器测得的最大温度变化范围为7.3K至50.7K。最初选择的体素中的中值RMS平均温差范围为1.4K至3.4K。温度差异在0.5K至0.9K之间。微波天线和MRI条件室内微波发生器未诱发相关的射频伪影。
结论：在凝胶体模中，微波加热过程中具有非常低的RMS平均温度误差低于1K的精确3D实时MRI温度映射是可行的。
结论：基于MRI的准确体积实时监测温度分布和热剂量与基于MRI的临床干预措施高度相关，并有望改善局部肿瘤控制，以及通过扩展热限制的程序安全(例如，微波）消融肝脏和其他器官中的肿瘤。
结论：介入MRI可以为肿瘤的微波消融提供全面的环境。MRI可以使用基于实时MRI的温度映射来监测微波消融。微波加热过程中的3D实时MRI温度映射是可行的。在凝胶体模中测量的温度误差低于1°C。有源室内微波发生器未引起任何相关的射频伪影。
方法：使用室内MR条件微波系统和MRI测温法在基于琼脂的凝胶体模中评估了九个体模实验。MRI测量进行700s（25片；时间分辨率2s）。用两个距离微波天线约5mm和10mm的光纤温度传感器监测温度。将传感器的温度曲线与传感器尖端处的感兴趣的单体素区域（ROI）的MRI温度数据进行比较；MRI测温的准确性被评估为均方根（RMS）平均温度差。还评估了原始ROI周围的18个相邻体素,并且另外选择具有最小温度差的体素用于进一步评估。
结果：光纤传感器测得的最大温度变化范围为7.3K至50.7K。最初选择的体素中的中值RMS平均温差范围为1.4K至3.4K。温度差异在0.5K至0.9K之间。微波天线和MRI条件室内微波发生器未诱发相关的射频伪影。
结论：在凝胶体模中，微波加热过程中具有非常低的RMS平均温度误差低于1K的精确3D实时MRI温度映射是可行的。
结论：基于MRI的准确体积实时监测温度分布和热剂量与基于MRI的临床干预措施高度相关，并有望改善局部肿瘤控制，以及通过扩展热限制的程序安全(例如，微波）消融肝脏和其他器官中的肿瘤。
结论：介入MRI可以为肿瘤的微波消融提供全面的环境。MRI可以使用基于实时MRI的温度映射来监测微波消融。微波加热过程中的3D实时MRI温度映射是可行的。在凝胶体模中测量的温度误差低于1°C。有源室内微波发生器未引起任何相关的射频伪影。
