Investigating hydroxyl chemical exchange using a variable saturation power chemical exchange saturation transfer (vCEST) method at 3 T.
Investigating hydroxyl chemical exchange using a variable saturation power chemical exchange saturation transfer (vCEST) method at 3 T.
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DOI：
10.1002/mrm.25987
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发表时间：
2016-09
影响因子：
3.3
通讯作者：
Smith SA
中科院分区：
文献类型：
--
作者：
Clark DJ;Smith AK;Dortch RD;Knopp MV;Smith SA
开发对3T处的羟基质子敏感的CEST饱和方案。羟基部分的临床成像可对骨关节炎、神经精神障碍和癌症产生影响。通过随频偏线性变化饱和幅度，Z谱的直接含水饱和度分量被展平，并可被减去以产生隔离溶质共振的差谱(MTRdiff)。可变的饱和功率允许在一个Z-光谱中对羟基和胺/酰胺部分进行近乎最优化。模型研究被用来测试vCEST在两种环境中的性能：(1)水中单一溶质(糖原，葡萄糖)；(2)水中多溶质(糖原与BSA)。对一位有软骨移植病史的受试者进行了在体软骨-股软骨糖胺聚糖含量(GAG)的vCEST成像。在具有重叠共振的溶液中，vCEST解析单独的羟基峰和胺/酰胺峰。软骨中的CEST羟基信号可忽略不计，但对于vCEST，羟基信号的范围为2-5%·ppm，病变软骨与正常软骨之间有明显的反差。介绍了一种可变饱和幅度CEST(VCEST)方案，以提高在3T时对可交换羟基部分的灵敏度，从而在具有重叠共振的多个溶质存在的情况下检测羟基。
To develop a CEST saturation scheme sensitive to hydroxyl protons at 3 T. Clinical imaging of hydroxyl moieties can have an impact on osteoarthritis, neuropsychiatric disorders, cancer. By varying saturation amplitude linearly with frequency offset, the direct water saturation component of the Z-spectrum is flattened and can be subtracted to produce a difference spectrum (MTRdiff) that isolates solute resonances. Variable saturation power allows for near optimization of hydroxyl and amine/amide moieties in one Z-spectrum. Phantom studies were used to test vCEST performance in 2 environments: (1) aqueous single-solute (glycogen, glucose); (2) aqueous multiple solute (glycogen with BSA). In vivo vCEST imaging of glycosaminoglycan content (GAG) in patellar-femoral cartilage was performed in a subject with history of cartilage transplant. In solutions with overlapping resonances, vCEST resolves separate hydroxyl and amine/amide peaks. CEST hydroxyl signal in cartilage is negligible, but with vCEST, hydroxyl signal ranged from 2 – 5%·ppm and showed distinct contrast between lesions and normal appearing cartilage. Introduced a variable saturation amplitude CEST (vCEST) scheme to improve sensitivity to exchangeable hydroxyl moieties at 3 T resulting in detection of hydroxyl in the presence of multiple solutes with overlapping resonances.