Rieke Viola, Kinsey Adam M, Ross Anthony B, Nau William H, Diederich Chris J, Sommer Graham, Pauly Kim Butts
Radiological Sciences Laboratory, Department of Radiology, Stanford University, Stanford, CA 94305, USA.
IEEE Trans Med Imaging. 2007 Jun;26(6):813-21. doi: 10.1109/TMI.2007.892647.
Referenceless proton resonance frequency (PRF) shift thermometry provides a means to measure temperature changes during minimally invasive thermotherapy that is inherently robust to motion and tissue displacement. However, if the referenceless method is used to determine temperature changes during prostate ablation, phase gaps between water and fat in image regions used to determine the background phase can confound the phase estimation. We demonstrate an extension to referenceless thermometry which eliminates this problem by allowing background phase estimation in the presence of phase discontinuities between aqueous and fatty tissue. In this method, images are acquired with a multiecho sequence and binary water and fat maps are generated from a Dixon reconstruction. For the background phase estimation, water and fat regions are treated separately and the phase offset between the two tissue types is determined. The method is demonstrated feasibile in phantoms and during in vivo thermal ablation of canine prostate.
无参考质子共振频率（PRF）偏移测温法提供了一种在微创热疗期间测量温度变化的方法，该方法对运动和组织位移具有内在的鲁棒性。然而，如果使用无参考方法来确定前列腺消融期间的温度变化，用于确定背景相位的图像区域中水和脂肪之间的相位间隙会混淆相位估计。我们展示了一种无参考测温法的扩展，通过在水性和脂肪组织之间存在相位不连续性的情况下允许背景相位估计来消除此问题。在该方法中，使用多回波序列采集图像，并通过狄克逊重建生成二元水和脂肪图。对于背景相位估计，分别处理水和脂肪区域，并确定两种组织类型之间的相位偏移。该方法在体模以及犬前列腺的体内热消融过程中被证明是可行的。
