Dehkharghani S, Mao H, Howell L, Zhang X, Pate K S, Magrath P R, Tong F, Wei L, Qiu D, Fleischer C, Oshinski J N
From the Department of Radiology and Imaging Sciences (S.D., H.M., K.S.P., F.T., D.Q., J.N.O.), Emory University Hospital, Atlanta, Georgia
From the Department of Radiology and Imaging Sciences (S.D., H.M., K.S.P., F.T., D.Q., J.N.O.), Emory University Hospital, Atlanta, Georgia.
AJNR Am J Neuroradiol. 2015 Jun;36(6):1128-35. doi: 10.3174/ajnr.A4241. Epub 2015 Feb 5.
Applications for noninvasive biologic temperature monitoring are widespread in biomedicine and of particular interest in the context of brain temperature regulation, where traditionally costly and invasive monitoring schemes limit their applicability in many settings. Brain thermal regulation, therefore, remains controversial, motivating the development of noninvasive approaches such as temperature-sensitive nuclear MR phenomena. The purpose of this work was to compare the utility of competing approaches to MR thermometry by using proton resonance frequency chemical shift. We tested 3 methodologies, hypothesizing the feasibility of a fast and accurate approach to chemical shift thermometry, in a phantom study at 3T.
A conventional, paired approach (difference [DIFF]-1), an accelerated single-scan approach (DIFF-2), and a new, further accelerated strategy (DIFF-3) were tested. Phantom temperatures were modulated during real-time fiber optic temperature monitoring, with MR thermometry derived simultaneously from temperature-sensitive changes in the water proton chemical shift (∼0.01 ppm/°C). MR thermometry was subsequently performed in a series of in vivo nonhuman primate experiments under physiologic and ischemic conditions, testing its reproducibility and overall performance.
Chemical shift thermometry demonstrated excellent agreement with phantom temperatures for all 3 approaches (DIFF-1: linear regression R(2) = 0.994; P < .001; acquisition time = 4 minutes 40 seconds; DIFF-2: R(2) = 0.996; P < .001; acquisition time = 4 minutes; DIFF-3: R(2) = 0.998; P < .001; acquisition time = 40 seconds).
These findings confirm the comparability in performance of 3 competing approaches to MR thermometry and present in vivo applications under physiologic and ischemic conditions in a primate stroke model.
非侵入性生物体温监测在生物医学中应用广泛，在脑体温调节方面尤其受到关注，传统上成本高昂且具有侵入性的监测方案限制了其在许多情况下的适用性。因此，脑热调节仍存在争议，这促使了诸如温度敏感型核磁共振现象等非侵入性方法的发展。本研究的目的是通过使用质子共振频率化学位移来比较磁共振测温的不同竞争方法的效用。我们测试了3种方法，在3T的体模研究中假设一种快速准确的化学位移测温方法的可行性。
测试了一种传统的配对方法（差值[DIFF]-1）、一种加速单扫描方法（DIFF-2）和一种新的、进一步加速的策略（DIFF-3）。在实时光纤温度监测期间调节体模温度，同时通过水质子化学位移的温度敏感变化（约0.01 ppm/°C）得出磁共振测温结果。随后在一系列生理和缺血条件下的体内非人灵长类动物实验中进行磁共振测温，测试其重现性和整体性能。
对于所有3种方法，化学位移测温与体模温度显示出极好的一致性（DIFF-1：线性回归R(2)=0.994；P<.001；采集时间=4分40秒；DIFF-2：R(2)=0.996；P<.001；采集时间=4分钟；DIFF-3：R(2)=0.998；P<.001；采集时间=40秒）。
这些发现证实了3种竞争的磁共振测温方法在性能上的可比性，并展示了在灵长类中风模型的生理和缺血条件下的体内应用。
