Robust mapping of relaxation parameters in ex vivo tissues is based on hydration and therefore requires control of the tissue treatment to ensure tissue integrity and consistent measurement conditions over long periods of time. One way to maintain the hydration of ex vivo tendon tissue is to immerse the samples in a buffer solution. To this end, various buffer solutions have been proposed; however, many appear to influence the tissue relaxation times, especially with prolonged exposure. In this work, ovine Achilles tendon tissue was used as a model to investigate the effect of immersion in phosphate-buffered saline (PBS) and the effects on the T1 and T2 * relaxation times. Ex vivo samples were measured at 0 (baseline), 30 and 67 hours after immersion in PBS. Ultrashort echo time (UTE) imaging was performed using variable flip angle and echo train-shifted multi-echo imaging for T1 and T2 * estimation, respectively. Compared with baseline, both T1 and T2 * relaxation time constants increased significantly after 30 hours of immersion. T2 * continued to show a significant increase between 30 and 67 hours. Both T1 and T2 * tended to approach saturation at 67 hours. These results exemplify the relevance of stringently controlled tissue preparation and preservation techniques, both before and during MRI experiments.

中文翻译：

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阿喀琉斯腱浸入磷酸盐缓冲液中会影响T1和T2 *松弛时间：一项离体研究。

活体外组织中松弛参数的稳健映射基于水合作用，因此需要控制组织处理以确保组织的完整性和长期的一致测量条件。维持离体肌腱组织水合作用的一种方法是将样品浸入缓冲溶液中。为此，已经提出了各种缓冲溶液。但是，许多因素似乎会影响组织的松弛时间，尤其是长时间的暴露。在这项工作中，以绵羊跟腱组织为模型，研究了浸入磷酸盐缓冲盐水（PBS）中的效果以及对T1和T2 *松弛时间的影响。浸入PBS后0、30和67小时测量离体样品。超短回波时间（UTE）成像是使用可变的翻转角和回波移动多回波成像分别进行T1和T2 *估计的。与基线相比，浸入30小时后T1和T2 *弛豫时间常数均显着增加。T2 *在30到67小时之间继续显示出显着增加。T1和T2 *在67小时都趋于饱和。这些结果证明了在MRI实验之前和期间严格控制组织制备和保存技术的相关性。T1和T2 *在67小时都趋于饱和。这些结果证明了在MRI实验之前和期间严格控制组织制备和保存技术的相关性。T1和T2 *在67小时都趋于饱和。这些结果证明了在MRI实验之前和期间严格控制组织制备和保存技术的相关性。