In vivo assessment of extracellular pH of joint tissues using acidoCEST-UTE MRI
In vivo assessment of extracellular pH of joint tissues using acidoCEST-UTE MRI
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DOI：
10.21037/qims.2019.08.11
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发表时间：
2019-10-01
影响因子：
2.8
通讯作者：
Chang, Eric Y.
中科院分区：
文献类型：
--
作者：
High, Rachel A.;Ji, Yang;Chang, Eric Y.
背景：软骨和半月板的降解可能是由细胞外pH值的变化介导的。本研究的目的是优化使用三维超短回波时间读出（acidoCEST- ute）的acidoCEST磁共振成像（MRI）技术的饱和功率，并证明该方法在体内测量软骨和半月板pH值的可行性。方法：观察异帕米醇和碘己醇在软骨和半月板组织模型中不同功率下的磁化传递比不对称和射频功率失配比。采用优化的射频功率，采用acidoCEST-UTE MRI序列评估4例患者关节内直接给予碘造影剂后关节液和组织的pIl。结果：在幻影中，0.54/1.10 μ T的幂比值与pH的相关性最强。体内acicloCEST-UTE关节内液的pH值与造影剂的电极测量值相似（iopamidol为7.22 vs. 7.1； iohexol为7.65 vs. 7.5）。用acidoCEST-UTE技术测量，整体平均软骨pH值显著低于整体平均半月板pH值（分别为6.60和6.72，P=0.043）。结论：在关节内直接给药碘帕美或碘己醇后，可以使用醋酸醋酸酯- ute MRI测量软骨和半月板的体内pH值。
Background: Degradation of cartilage and meniscus may be mediated by changes in extracellular pH. The purpose of this study was to optimize saturation powers used with the acidoCEST magnetic resonance imaging (MRI) technique with a 3D ultrashort echo time readout (acidoCEST-UTE) and to demonstrate feasibility of the method for measuring pH in cartilage and meniscus in vivo.Methods: Magnetization transfer ratio asymmetry and ratio of radiofrequency (RF) power mismatch at different powers were evaluated in cartilage and meniscus tissue phantoms for iopamidol and iohexol. Using optimized RF powers, the acidoCEST-UTE MRI sequence was used to assess pIl of joint fluid and tissues in four patients after direct intra-articular administration of iodinated contrast.Results: In the phantoms, the ratio of powers 0.54/1.10 mu T showed the strongest correlation with pH. In vivo acicloCEST-UTE pH measurements of intra-articular fluid were similar to electrode measurements of the contrast agent (7.22 vs. 7.1 for iopamidol, respectively; 7.65 vs. 7.5 for iohexol, respectively). As measured with the acidoCEST-UTE technique, overall mean cartilage pH was significantly lower than overall mean meniscus pH (6.60 vs. 6.72, respectively; P=0.043).Conclusions: AcidoCEST-UTE MRI after direct intra-articular administration of either iopamidol or iohexol can be used to measure cartilage and meniscus pH in vivo.