优化7-T化学交换饱和转移参数以验证纤维腺性乳腺组织的糖胺聚糖和酰胺质子转移
Optimization of 7-T chemical exchange saturation transfer parameters for validation of glycosaminoglycan and amide proton transfer of fibroglandular breast tissue.
作者信息
Dula Adrienne N, Dewey Blake E, Arlinghaus Lori R, Williams Jason M, Klomp Dennis, Yankeelov Thomas E, Smith Seth
机构信息
From the Institute of Imaging Science (A.N.D., B.E.D., L.R.A., J.M.W., D.K., T.E.Y., S.S.), Department of Radiology and Radiological Sciences (A.N.D., T.E.Y., S.S.), Program in Chemical and Physical Biology (T.E.Y., S.S.), Department of Biomedical Engineering (T.E.Y., S.S.), Department of Physics and Astronomy (T.E.Y., S.S.), Department of Cancer Biology (T.E.Y.), and Vanderbilt Ingram Cancer Center (T.E.Y.), Vanderbilt University Medical Center, AA-1105 Medical Center North, 1161 21st Ave S, Nashville, TN 37232-2310; and Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands.
出版信息
Radiology. 2015 Apr;275(1):255-61. doi: 10.1148/radiol.14140762. Epub 2014 Oct 29.
PURPOSE
To (a) implement simulation-optimized chemical exchange saturation transfer (CEST) measurements sensitive to amide proton transfer (APT) and glycosaminoglycan (GAG) hydroxyl proton transfer effects in the human breast at 7 T and (b) determine the reliability of these techniques for evaluation of fibroglandular tissue in the healthy breast as a benchmark for future studies of pathologic findings.
MATERIALS AND METHODS
All human studies were institutional review board approved, were HIPAA compliant, and included informed consent. The CEST parameters of saturation duration (25 msec) and amplitude (1 μT) were chosen on the basis of simulation-driven optimization for APT contrast enhancement with the CEST effect quantified by using residuals of a Lorentzian fit. Optimized parameters were implemented at 7 T in 10 healthy women in two separate examinations to evaluate the reliability of CEST magnetic resonance (MR) imaging measurements in the breast. CEST z-spectra were acquired over saturation offset frequencies ranging between ±40 ppm by using a quadrature unilateral breast coil. The imaging-repeat imaging reliability was assessed in terms of the intraclass correlation coefficient, which indicates the ratio of between-subject variation to total variation.
RESULTS
Simulations were performed of the Bloch equations with chemical exchange-guided selection of optimal values for pulse duration and amplitude, 25 msec and 1 μT, respectively. Reliability was evaluated by using intraclass correlation coefficients (95% confidence intervals), with acceptable results: 0.963 (95% confidence interval: 0.852, 0.991) and 0.903 (95% confidence interval: 0.609, 0.976) for APT and GAG, respectively.
CONCLUSION
Simulations were used to derive optimal CEST preparation parameters to elicit maximal CEST contrast enhancement in healthy fibroglandular breast tissue due to APT at 7 T. By using these parameters, reproducible values were obtained for both the amide and hydroxyl protons from CEST MR imaging at 7 T and are feasible in the human breast.
目的
(a) 在7T磁场下，实施对人乳腺中酰胺质子转移（APT）和糖胺聚糖（GAG）羟基质子转移效应敏感的模拟优化化学交换饱和转移（CEST）测量；(b) 确定这些技术评估健康乳腺中纤维腺组织的可靠性，作为未来病理学研究结果的基准。
材料与方法
所有人体研究均经机构审查委员会批准，符合健康保险流通与责任法案（HIPAA）要求，并获得了知情同意书。基于模拟驱动优化选择饱和持续时间（25毫秒）和幅度（1微特斯拉）的CEST参数，以增强APT对比度，并使用洛伦兹拟合残差量化CEST效应。在7T磁场下，对10名健康女性进行了两次独立检查，实施优化后的参数，以评估CEST磁共振（MR）成像测量在乳腺中的可靠性。使用正交单侧乳腺线圈，在±40 ppm的饱和偏移频率范围内采集CEST z谱。根据组内相关系数评估成像-重复成像的可靠性，该系数表示受试者间变异与总变异的比率。
结果
针对布洛赫方程进行了模拟，通过化学交换指导分别选择了脉冲持续时间和幅度的最佳值，分别为25毫秒和1微特斯拉。使用组内相关系数（95%置信区间）评估可靠性，结果可接受：APT和GAG的组内相关系数分别为0.963（95%置信区间：0.852, 0.991）和0.903（95%置信区间：0.609, 0.976）。
结论
通过模拟得出了最佳的CEST制备参数，以在7T磁场下，因APT效应在健康的乳腺纤维腺组织中引发最大的CEST对比度增强。使用这些参数，在7T磁场下通过CEST MR成像获得了酰胺质子和羟基质子的可重复值，且在人体乳腺中是可行的。
Zotero 插件