Grant R, Condon B, Moyns S, Patterson J, Hadley D, Teasdale G
Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland.
Magn Reson Med. 1988 Apr;6(4):397-402. doi: 10.1002/mrm.1910060405.
Documented relaxation time measurements of body fluids such as cerebrospinal fluid (CSF) vary considerably. This may be largely due to lack of an appropriate method of maintaining the in vivo physiological and biochemical characteristics of the fluid. We have developed an in vitro technique that maintains the in vivo characteristics of body fluid samples for a sufficiently long period to establish the true relaxation times. To illustrate this we studied changes in CSF pH, pO2, and pCO2, first as it equilibrated with air and then under anaerobic conditions as found in vivo. Relaxation times of CSF were then studied under aerobic and anaerobic conditions. Under the particular aerobic conditions used the pH and pO2 of CSF increased quickly and pCO2 fell within the first 30 min. By 3-4 h equilibration with air was complete. The T1 and T2 relaxation times of CSF decreased by 14 and 16%, respectively, as a result of these physicochemical changes. It is important that such changes be considered when relaxation measurements of any body fluid are performed in vitro and efforts to maintain the in vivo milieu should not be neglected.
诸如脑脊液（CSF）等体液的弛豫时间测量记录差异很大。这可能在很大程度上是由于缺乏一种维持该液体体内生理和生化特性的合适方法。我们已经开发出一种体外技术，该技术可将体液样本的体内特性维持足够长的时间以确定真正的弛豫时间。为了说明这一点，我们研究了脑脊液的pH值、pO2和pCO2的变化，首先是其与空气平衡时的变化，然后是在体内发现的厌氧条件下的变化。然后研究了脑脊液在有氧和厌氧条件下的弛豫时间。在所使用的特定有氧条件下，脑脊液的pH值和pO2迅速升高，pCO2在最初30分钟内下降。到3 - 4小时，与空气的平衡完成。由于这些物理化学变化，脑脊液的T1和T2弛豫时间分别下降了14%和16%。当在体外进行任何体液的弛豫测量时，考虑到这些变化很重要，并且维持体内环境的努力不应被忽视。
