Can MTR be used to assess cartilage in the presence of Gd-DTPA2-?
Can MTR be used to assess cartilage in the presence of Gd-DTPA2-?
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DOI：
10.1002/mrm.10322
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发表时间：
2002-12-01
影响因子：
3.3
通讯作者：
Burstein, D
中科院分区：
文献类型：
--
作者：
Henkelman, RM;Stanisz, GJ;Burstein, D
在不存在和存在Gd-DTPA（2-）的情况下，测量正常、胰蛋白酶处理和白细胞介素-1 β（IL-1 β）处理的软骨的磁化传递（MT）和T-1和T-2松弛。不加Gd-DTPA（2-）时，T-1和T-2的软骨损伤均无明显变化。然而，与Gd-DTPA（2-）相比，胰蛋白酶消化的软骨显示出比正常软骨明显更短的T-1，正如预期的那样，这是由于这些样品中的糖胺聚糖（GAG）损失以及相关的Gd-DTPA（2-）浓度增加。T-2的结果相似，但没有那么戏剧性。MT伪一级交换率RMOB不依赖于造影剂浓度，正如预期的那样，胰蛋白酶处理的软骨明显更快，IL-1 β处理的软骨更慢。在这两种情况下，MT部分的大分子池M-OB下降，而只有胰蛋白酶化的软骨显示出增加MT交换率R。MT比值（MTR）随Gd-DTPA（2-）浓度的增加而降低。然而，在Gd-DTPA（2-）的存在下的MTR结果的解释是复杂的，由于纵向弛豫和MT交换增加的竞争效应。因此，在GAG耗竭程度未知且胶原蛋白受损的软骨样本中，可使用完整的MT分析来探测软骨的分子状态，但不可能在给予Gd-DTPA（2-）后使用简单的MTR测量来差异性确定样本中软骨降解的量。
Magnetization transfer (MT) and T-1 and T-2 relaxation of normal, trypsinized, and interleukin-1beta (IL-1beta)-treated cartilage were measured in the absence and presence of Gd-DTPA(2-). Without the addition of Gd-DTPA(2-), neither T-1 nor T-2 showed any significant change with cartilage damage. However, with Gd-DTPA(2-), trypsinized cartilage exhibited substantially shorter T-1 than normal cartilage, as expected due to the glycosaminoglycan (GAG) loss in these samples, and associated increased Gd-DTPA(2-) concentration. The T-2 results were similar, but less dramatic. The MT pseudo first-order exchange rate, RMOB, did not depend on the contrast agent concentration, as expected, and was significantly faster for trypsinized and slower for IL-1beta-treated cartilage. In both cases, the MT fraction of the macromolecular pool M-OB decreased while only trypsinized cartilage showed an increase in MT exchange rate R. The MT ratio (MTR) decreased with increasing Gd-DTPA(2-) concentration. However, interpretation of the MTR results in the presence of Gd-DTPA(2-) was complicated due to competing effects of increased longitudinal relaxivity and MT exchange. Therefore, in a cartilage sample with an unknown degree of GAG depletion and some collagen damage, a full MT analysis might be used to probe the molecular state of cartilage, but it would not be possible to use a simple MTR measurement after the administration of Gd-DTPA(2-) to differentially determine the amount of cartilage degradation in the sample.