Department of Radiodiagnosis and Diagnostic Imaging, Faculty of Medicine, Alexandria University, 1 Kolya-El Teb St., Mahata El-Ramel, Alexandria, Egypt.
Eur J Radiol. 2011 Nov;80(2):559-64. doi: 10.1016/j.ejrad.2010.12.011. Epub 2011 Jan 16.
Protein binding and relaxivity are major determinants of the relative effectiveness of an MR arthrographic contrast agent. We sought to evaluate the optimal concentrations of high and usual relaxivity agents in two different proteinous environments at variable field strength for two MR contrast agents of different relaxivities.
At 1.5, 3.0 and 7.0 T, gadobenate dimeglumine (Multihance) with high-relaxivity in proteinous environment and gadoteridol (Prohance) with more typical behavior were studied at 1.25, 2.5, 5, and 10 mmol in 1.7 g/dL and 3g/dL albumin (mimicking protein content of normal and inflammatory synovial fluids, respectively) vs. pure normal saline, as a control. Analysis of image signal intensity (SI) and relaxivity values was done.
In our study a change in concentration had no significant effect on T1 SI. In contrast, nearly every change in concentration led to a significant change in T2 SI. In 1.25 mmol concentration, there was no effect on T1 SI of either protein concentrations while higher concentrations showed significant decreased SI in either protein carrier compared to saline. The SI of Gadoteridol was significantly higher (p<0.0001) than that of gadobenate at each of 3T and 7 T, but was significantly lower (p<0.001) at 1.5 T in saline solution while this was not significant for either protein carrier. Both protein carriers had significant effect on T1 (p=0.0124) and T2 (p=0.0118) relaxivities. Also solution concentration significantly (p<0.01) affected both T1 and T2 relaxivities. Field strength did not affect T1 relaxivity (p=0.02511) while it significantly affected T2 relaxivity (p<0.001). This was significant (p=0.035) in case of gadoteridol at 3T.
1.25 mmol concentration of both gadoteridol and gadobenate solutions yields the best diagnostic T1 SI specially in higher fields (3T and 7 T) and avoid the deleterious effect of increasing concentration on T2 SI. Gadoteridol is suggested on 3T field indirect MR arthrograms. Protein had no positive effect on either SI or relaxivities in any joint model.
蛋白结合和弛豫率是磁共振关节造影对比剂相对效能的主要决定因素。我们旨在评估两种弛豫率不同的磁共振对比剂在两种不同蛋白环境中的不同场强下的高弛豫率和常规弛豫率试剂的最佳浓度。
在 1.5、3.0 和 7.0T 下，研究了高弛豫率的钆贝葡胺（Multihance）和更典型行为的钆特醇（Prohance）在分别模拟正常和炎症性滑液蛋白含量的 1.7g/dL 和 3g/dL 白蛋白（分别模拟正常和炎症性滑液的蛋白含量）中和纯生理盐水（作为对照）中的 1.25、2.5、5 和 10mmol 浓度下的表现。分析图像信号强度（SI）和弛豫率值。
在我们的研究中，浓度变化对 T1 SI 没有显著影响。相反，几乎每次浓度变化都会导致 T2 SI 显著变化。在 1.25mmol 浓度下，两种蛋白浓度对 T1 SI 均无影响，而较高浓度会导致两种蛋白载体与生理盐水相比，SI 显著降低。在 3T 和 7T 下，钆特醇的 SI 均显著高于（p<0.0001）钆贝葡胺，但在生理盐水溶液中，1.5T 时差异显著（p<0.001），而在两种蛋白载体中则不显著。两种蛋白载体均对 T1（p=0.0124）和 T2（p=0.0118）弛豫率有显著影响。此外，溶液浓度对 T1 和 T2 弛豫率均有显著影响（p<0.01）。场强对 T1 弛豫率无影响（p=0.02511），但对 T2 弛豫率有显著影响（p<0.001）。在 3T 时，这在钆特醇中具有显著意义（p=0.035）。
在较高场强（3T 和 7T）下，1.25mmol 浓度的钆特醇和钆贝葡胺溶液可获得最佳诊断 T1 SI，并避免浓度增加对 T2 SI 的有害影响。在 3T 场间接磁共振关节造影中建议使用钆特醇。在任何关节模型中，蛋白对 SI 或弛豫率均无积极影响。
