Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Magn Reson Med. 2017 Sep;78(3):1110-1120. doi: 10.1002/mrm.26470. Epub 2016 Sep 30.
The purpose of this work was to determine the predictive value of chemical exchange saturation transfer (CEST) metrics in brain metastases treated with stereotactic radiosurgery (SRS).
CEST spectra at a radiofrequency power of 0.52 µT were collected on a 3 Tesla (T) magnetic resonance imaging from 25 patients at three time points: pretreatment, 1 week, and 1 month post-treatment. Amide proton transfer-weighted images and maps of the amplitude and width of Lorentzian-shaped CEST peaks and the relaxation-compensated AREX metric were constructed at the offset frequencies of amide, amine, and relayed nuclear Overhauser effect (NOE) from aliphatic groups as well as the broad magnetization transfer effect. Pretreatment CEST metrics, as well as CEST metric changes at 1 week post-treatment, were compared to changes in tumor volume at 1 month.
Significant (P < 0.05) 1-week predictive metrics included NOE peak amplitude (R = 0.69) in normal-appearing white matter (NAWM) and width (R = -0.55) in tumor. Baseline NOE in contralateral NAWM was negatively correlated (R = -0.69) with volume changes at 1 month. Metrics-defined outside tumor margins had higher correlation with volume changes than tumor regions of interest.
CEST metrics, in particular, the NOE peak amplitude, can predict volume changes 1 month post-SRS. Magn Reson Med 78:1110-1120, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
本研究旨在探讨化学交换饱和转移（CEST）指标在立体定向放射外科（SRS）治疗脑转移瘤中的预测价值。
在 3.0T 磁共振成像仪上，对 25 例患者进行了 0.52μT 射频功率的 CEST 谱采集，采集时间点为治疗前、治疗后 1 周和 1 个月。构建了酰胺质子转移加权图像和洛伦兹形 CEST 峰幅度和宽度以及弛豫补偿的 AREX 指标的图谱，以及来自脂肪族基团的酰胺、胺和中继核奥弗豪瑟效应（NOE）的偏移频率以及宽磁共振转移效应。比较了治疗前 CEST 指标和治疗后 1 周的 CEST 指标变化与 1 个月时肿瘤体积的变化。
在正常外观的白质（NAWM）和肿瘤中的 NOE 峰幅度（R=0.69）和宽度（R=-0.55）等有意义的（P<0.05）1 周预测指标发生了显著变化。对侧 NAWM 中的基线 NOE 与 1 个月时的体积变化呈负相关（R=-0.69）。与肿瘤感兴趣区相比，定义在肿瘤边界外的指标与体积变化具有更高的相关性。
特别是 CEST 指标中的 NOE 峰幅度，可以预测 SRS 治疗后 1 个月的体积变化。磁共振医学 78:1110-1120, 2017. © 2016 国际磁共振学会。
