Schmitt B, Zamecnik P, Zaiss M, Rerich E, Schuster L, Bachert P, Schlemmer H P
Center for High Field MR, Medical University of Vienna.
Rofo. 2011 Nov;183(11):1030-6. doi: 10.1055/s-0031-1281764. Epub 2011 Oct 27.
To evaluate the feasibility to detect and delineate malignant breast lesions in human patients by chemical exchange saturation transfer (CEST) as an MR imaging technique without the need for contrast agent administration.
Six female patients referred for pre-surgical staging due to histologically confirmed breast cancer were examined with MR at 3 T. The routine breast protocol included T (2w), STIR, T (1w)-DCE and contrast-enhanced T (1w) imaging with SPAIR fat suppression. For CEST imaging, a 3D RF-spoiled gradient echo (GRE) sequence with an optimized saturation pulse train was applied. To assess the diagnostic value of the technique, CEST effects observed between frequency offsets of 1.2 to 1.8 ppm from the bulk water resonance were compared to pharmacokinetic parameter maps (k (ep)) obtained by DCE-MRI.
In 3 of 6 patients, regions with high CEST signal intensity correlated well with tumor areas as determined by DCE-MRI. Analysis of signal intensities from ROIs in tumor, fibroglandular, adipose, and muscle tissue revealed significantly higher CEST values in tumor tissue compared to fibroglandular tissue. The detection of lesions was equally well possible with DCE-MRI and CEST-MRI. In the three other patients, the tumor regions could not be delineated based on the CEST image due to artifacts, which were most likely caused by a high content of fat tissue within the ROIs.
The results of this initial feasibility study indicate a significant potential of CEST-MRI to discriminate cancer from fibroglandular tissue in the human breast by a CEST contrast generated by endogenous solute molecules.
评估将化学交换饱和转移（CEST）作为一种无需注射造影剂的磁共振成像技术来检测和描绘人类患者乳腺恶性病变的可行性。
对6名因组织学确诊为乳腺癌而接受术前分期的女性患者进行3T磁共振检查。常规乳腺检查方案包括T2加权成像（T2w）、短TI反转恢复序列（STIR）、T1加权动态对比增强成像（T1w-DCE）以及采用SPAIR脂肪抑制的对比增强T1加权成像。对于CEST成像，应用了具有优化饱和脉冲序列的三维射频扰相梯度回波（GRE）序列。为评估该技术的诊断价值，将从总体水共振频率偏移1.2至1.8 ppm之间观察到的CEST效应与通过动态对比增强磁共振成像（DCE-MRI）获得的药代动力学参数图（kep）进行比较。
6名患者中有3名患者，CEST信号强度高的区域与DCE-MRI确定的肿瘤区域相关性良好。对肿瘤、纤维腺组织、脂肪组织和肌肉组织中感兴趣区域（ROI）的信号强度分析显示，与纤维腺组织相比，肿瘤组织中的CEST值明显更高。DCE-MRI和CEST-MRI对病变的检测效果相当。在另外三名患者中，由于伪影，基于CEST图像无法描绘肿瘤区域，这些伪影很可能是由ROI内高含量的脂肪组织引起的。
这项初步可行性研究的结果表明，CEST-MRI具有通过内源性溶质分子产生的CEST对比在人类乳腺中区分癌症与纤维腺组织的巨大潜力。
