Multislice CEST MRI improves the spatial assessment of tumor pH.
Multislice CEST MRI improves the spatial assessment of tumor pH.
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多层CEST MRI改善了肿瘤pH的空间评估。
DOI：
10.1002/mrm.26348
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发表时间：
2017-07
影响因子：
3.3
通讯作者：
Cárdenas-Rodríguez J
中科院分区：
文献类型：
--
作者：
Randtke EA;Granados JC;Howison CM;Pagel MD;Cárdenas-Rodríguez J
需要细胞外pH(Phe)的多层图来询问肿瘤和正常器官的异质性。为了满足这一需求，我们开发了一种带有CEST光谱拟合法的多层ACIDOCEST MRI采集方法，该方法可以在6.3到7.4的范围内测量活体PHE。采用相位偏移多平面(POMP)方法对CEST-FISPMRI进行多层螺旋CT扫描，获得单个CEST饱和脉冲的图像。对Bloch-McConnell方程进行了修改，以包括基于对比剂碘帕米多的pH和化学交换率的校准的pH。这些方程被用来估计肿瘤、肾脏、膀胱和其他组织的多层ACIDOCEST MR图像中的像素化Phe值。多层ACIDoCEST MRI成功地定位了从肿瘤核心到边缘的Phe从6.73到6.81个单位的梯度，以及跨越小鼠肾脏的Phe 6.56到6.97的梯度。膀胱被发现为Phe 6.3。AcidoCEST MRI结合Pomp采集和Bloch-McConnel分析，可以通过肿瘤、肾脏和膀胱在多个成像层面上映射Phe。这种多层评估有助于评估组织PHE的空间异质性。
Multislice maps of extracellular pH (pHe) are needed to interrogate the heterogeneities of tumors and normal organs. To address this need, we have developed a multislice acidoCEST MRI acquisition method with a CEST spectrum fitting method that measures in vivo pHe over a range of 6.3 to 7.4. The Phase Offset MultiPlanar (POMP) method was adapted for CEST-FISP MRI to acquire multiple image slices with a single CEST saturation pulse. The Bloch-McConnell equations were modified to include pH based on a calibration of pH and chemical exchange rate for the contrast agent, iopamidol. These equations were used to estimate the pixelwise pHe values throughout the multislice acidoCEST MR images of the tumor, kidney, bladder and other tissues of a MDA-MB-231 tumor model. Multislice acidoCEST MRI successfully mapped a gradient of pHe from 6.73 to 6.81 units from the tumor core to rim, and mapped a gradient of pHe 6.56 to 6.97 across the mouse kidney. The bladder was found to be pHe 6.3. AcidoCEST MRI with POMP acquisition and Bloch-McConnel analysis can map pHe in multiple imaging slices through the tumor, kidney, and bladder. This multislice evaluation facilitates assessments of spatial heterogeneity of tissue pHe.