MRI无创测温技术在高强度聚焦超声损伤活体羊肝组织中的应用

Application of Non-invasive Temperature-measured Technique using MRI in Monitoring High Intensity Focused Ultrasound Radiation Argali′s Livers In Vivo

目的磁共振成像(MRI)无创测温技术实时监测高强度聚焦超声(HIFU)辐照活体羊肝组织的靶区温度,观察靶区温度的分布特点。方法MRI导航高强度聚焦超声治疗系统(MRIgHIFU)定点连续辐照羊肝组织,GRE-T-MAP序列实时监测靶区温度并采集3s,6s,10s的温度图。结果GRE-T-MAP每3～4s采集一幅以不同颜色标示的温度图像:同一层面,靶区中心温度最高,周围依次降低;焦点层面的平均温度比其前、后层面高。靶区温度随辐照时间延长而增高,辐照10s时焦点层面平均温度(63.03±5.39)℃,最高温度(76.19±2.98)℃。结论GRE-T-MAP序列能准确获取靶区及其周围的温度范围,MRI测温技术可用于评价HIFU辐照活体动物肝脏的效果,为进一步研究磁共振导航高强度聚焦超声治疗系统的临床应用奠定基础。

Objective To monitor real-time temperature of Argali＇s livers in vivo under high intensity focused ultrasound （HIFU） radiation and to observe temperature distribution of target area using magnetic resonance imaging （MRI）. Methods Normal livers were under uninterrupted radiation by HIFU while dynamic temperature images were captured by GRE-T-MAP and images of radiation for 3 s,6 s,and 10 s were analyzed. Results GRE-T-MAP captured images of target temperatures labeled with different colors every 3-4 s. 31ae images showed that central temperature was much higher than that of the peripheral area in the same deck and that of the pre-and post deck. Target temperature was increasec with the prolongation of radiation time. The average temperature was （63.03±5.39） ℃ and the highest was （76.19±2.98）℃ at 10 s. Conclusion GRE-T-MAP can capture the temperature range of target and peripheral area accurately,therefore it can be used to evaluate the effects of HIFU in radiating livers with living animals and provide evidences for further study of MRIgHIFU in chnic.