Usefulness of MR imaging-derived thermometry and dosimetry in determining the threshold for tissue damage induced by thermal surgery in rabbits
Usefulness of MR imaging-derived thermometry and dosimetry in determining the threshold for tissue damage induced by thermal surgery in rabbits
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DOI：
10.1148/radiology.216.2.r00au42517
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发表时间：
2000-08-01
期刊：
影响因子：
19.7
通讯作者：
Hynynen, KH
中科院分区：
文献类型：
--
作者：
McDannold, NJ;King, RL;Hynynen, KH
目的：探讨利用磁共振成像(MR)获得的温度和热剂量测量确定热组织损伤阈值的可行性。材料和方法：在兔大腿肌肉中以不同功率进行超声照射。在超声治疗过程中获得的温度敏感的磁共振图像被用来估计温度和热剂量。然后将温度、热剂量和施加功率与超声后图像上观察到的组织损伤的发生相关联。八元相控阵换能器被用来产生空间平坦的温度分布，允许平均以减少噪声和体素大小的影响。结果：组织损伤的发生与磁共振成像的温度和热剂量测量有很好的相关性，但与施加的功率无关。当温度大于50.4℃，热剂量大于31.2当量分钟(43.0℃)时，所有部位都会发生组织损伤，当这些值小于47.2℃和4.3当量分钟时，均未发生组织损伤。结论：磁共振成像测温和剂量学可作为预测活体组织损伤阈值的指标。该指标改善了对微创热疗的在线控制，并应允许更准确的靶区凝固。
PURPOSE: To investigate in vivo the feasibility of using magnetic resonance (MR) imaging-derived temperature and thermal dose measurements to find the threshold of thermal tissue damage.MATERIALS AND METHODS: Sonications were delivered in rabbit thigh muscles at varying powers. Temperature-sensitive MR images obtained during the sonicatitions were used to estimate the temperature and thermal dose. The temperature, thermal dose, and applied power were then correlated to the occurrence of tissue damage observed on postsonication images. An eight-element phased-array transducer was used to produce spatially flat temperature profiles that allowed for averaging to reduce the effects of noise and the voxel size.RESULTS: The occurrence of tissue damage correlated well with MR imaging derived temperature and thermal dose measurements but not with the applied power. Tissue damage occurred at all locations with temperatures greater than 50.4 degrees C and thermal doses greater than 31.2 equivalent minutes at 43.0 degrees C. No tissue damage occurred when these values were less than 47.2 degrees C and 4.3 equivalent minutes.CONCLUSION: MR imaging thermometry and dosimetry provide an index to predict the threshold for tissue damage in vivo. This index offers improved online control over minimally invasive thermal treatments and should allow for more accurate target volume coagulation.