UCEPR: Ultrafast localized CEST-spectroscopy with PRESS in phantoms and in vivo.
UCEPR: Ultrafast localized CEST-spectroscopy with PRESS in phantoms and in vivo.
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DOI：
10.1002/mrm.25780
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发表时间：
2016-05
影响因子：
3.3
通讯作者：
Vinogradov E
中科院分区：
文献类型：
--
作者：
Liu Z;Dimitrov IE;Lenkinski RE;Hajibeigi A;Vinogradov E
化学交换饱和转移（CEST）是一种对比机制，通过从低浓度分子的可交换质子到本体水的饱和转移来增强低浓度分子。通常需要多次扫描才能形成Z光谱，这使得CEST方法非常耗时。在这里，提出了一种超快局部CEST光谱与PRESS（UCEPR），以获得一个体素的整个Z光谱，只使用两次扫描，显着加速CEST。该方法结合了超快非本地化CEST光谱与使用PRESS的本地化。场梯度与饱和脉冲同时施加，产生也被空间编码的所有Z谱频率的同时饱和。数据采集期间的读出梯度将CEST响应的空间依赖性解析为频率。UCEPR在3 T扫描仪上进行了体模和活体测试。在phantomy中，与传统CEST方法相比，以4-7倍的加速实现了多个pH变体碘帕醇样品的快速Z光谱采集。在活体条件下，以高频率分辨率（≤ 0.2ppm）在48 s内快速测定了健康人脑白色物质中的酰胺质子转移（APT）。与传统的CEST方法相比，UCEPR具有快速获得高分辨率Z谱的优点。潜在的体内应用包括超快局部Z光谱、定量或动态CEST研究。
Chemical Exchange Saturation Transfer (CEST) is a contrast mechanism enhancing low-concentration molecules through saturation transfer from their exchangeable protons to bulk water. Often many scans are acquired to form a Z-spectrum, making the CEST method time-consuming. Here, an ultrafast localized CEST-spectroscopy with PRESS (UCEPR) is proposed to obtain the entire Z-spectrum of a voxel using only two scans, significantly accelerating CEST. The approach combines ultrafast non-localized CEST spectroscopy with localization using PRESS. A field gradient is applied concurrently with the saturation pulse producing simultaneous saturation of all Z-spectrum frequencies that are also spatially encoded. A readout gradient during data acquisition resolves the spatial dependence of the CEST responses into frequency. UCEPR was tested on a 3T scanner both in phantoms and in vivo. In phantoms, a fast Z-spectroscopy acquisition of multiple pH-variant iopamidol samples was achieved with 4–7-fold acceleration as compared to the conventional CEST methods. In vivo, amide proton transfer (APT) in white matter of healthy human brain was measured rapidly in 48 s and with high frequency resolution (≤ 0.2 ppm). Compared to conventional CEST methods, UCEPR has the advantage of rapidly acquiring high-resolution Z-spectra. Potential in vivo applications include ultra-fast localized Z-spectroscopy, quantitative, or dynamic CEST studies.