Objective To acquire temperature maps and anatomic images during MRI-guided high-intensity focused ultrasound (MRgHIFU) treatment, so as to ensure the accuracy and safety of the treatment.Methods Independent phase encoding gradients were applied for the first echo and the second echo.One echo was encoded for acquiring high spatial resolution anatomic images, while the other was encoded for acquiring fast temperature maps.The temperature maps were overlayed on the anatomic images for monitoring the treatment.Ex-vivo experiments with ox liver as well as water phantom experiments were done for demonstrating the method.Results Ox liver heating experiments demonstrated that the displaying of temperature maps was better than the conventional method with the maximum updating speed of 1 frame/s.The sensitivity to motion was good, which was proved by phantom experiments.Conclusion The proposed MR duel-echo gradient sequence can achieve good results in terms of temperature monitoring and motion detecting during MRgHIFU experiments.%目的 利用MR梯度双回波脉冲序列监控高强度聚焦超声(MRgHIFU)治疗,同时获取温度图和解剖图,提高治疗的准确性和安全性.方法 在第一、第二个回波上分别施加独立的相位编码梯度,一个回波获取高分辨率的解剖图,另一个回波获取快速的温度图.将温度图叠加在解剖图上治疗监控.通过牛肝离体加热和水膜移动实验加以验证.结果 牛肝离体实验表明,在最快1幅/秒温度图时仍然可以很好地测量和显示温度,优于传统的温度图显示方法.水模实验证明此法对检测运动的敏感度较好,有利于监控治疗的准确性和安全性.结论利用MR梯度双回波脉冲序列可以在HIFU实验中更好地监控温度和检测运动.
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