一种用于乳腺微波热消融治疗温度成像的磁化率修正算法

An algorithm for correcting susceptibility induced breast temperature imaging during microwave ablation

在磁共振引导乳腺微波热消融手术过程中,温度成像方法可以算出被消融区域的准确温度.由于磁化率对温度变化很敏感,需要一种新的测温方法或者温度成像优化方法减小磁化率变化对测温准确性的影响.基于磁化率变化的温度成像优化方法首先使用最基本的温度成像方法求出热消融区域的温度;然后针对乳腺组织的特异性,使用水脂分离的温度成像方法计算温度,同时借助水和脂肪磁化率变化的差异性对温度进行修正;最后将温度差作为评估温度修正算法优劣的标准.仿真实验结果表明,对于包含水质两种组织的热消融模型,在微波消融输入功率为15W,微波消融时间为300s的时候,本算法的综合修正效果最好.上述结果证明了本算法的正确性以及可行性,适用于任何含有水和脂肪两种物质的组织.

During the interventional thermal therapy of beast caner by the hepatic microwave ablation （WMA） ,magnetic resonance （MR ） thermal imaging can obtain accurate temperature together with a reduction in the influence on the accuracy of the temperature caused by the change in the susceptibility of the WMA area .Because susceptibility is very sensitive to temperature change ,a new temperature mapping correction method was proposed to reduce the influence of the temperature imaging by susceptibility change .Firstly ,the temperature was calculated by the water proton resonance frequency （PRF） method . Secondly ,because breast tissue contains lots of fat ,the temperature was calculated by means of the water‐fat separating method based on differences in the susceptibility changes between water and fat .Lastly ,the temperature mapping correction method was evaluated by the temperature difference . The simulation results show that for a tissue model containing both water and fat ,when the power of the WMA is 15W , the temperature mapping accuracy can reach 0 .34 ℃ at the 300th second .All the results demonstrated the validity and feasibility of the temperature mapping correction method and its suitability for other tissues containing water and fat .