Neeb H, Zilles K, Shah N J
Institut für Medizin, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
Neuroimage. 2006 Jul 1;31(3):1156-68. doi: 10.1016/j.neuroimage.2005.12.063. Epub 2006 May 2.
The presence of brain edema, in its various forms, is an accompanying feature of many diseased states. Although the localized occurrence of brain edema may be demonstrated with MRI, the quantitative determination of absolute water content, an aspect that could play an important role in the objective evaluation of the dynamics of brain edema and the monitoring of the efficiency of treatment, is much more demanding. We present a method for the localized and quantitative measurement of absolute water content based on the combination of two fast multi-slice and multi-time point sequences QUTE and TAPIR for mapping the T(2)* and T(1) relaxation times, respectively. Incorporation of corrections for local B(1) field miscalibrations, temperature differences between the subject and a reference probe placed in the FOV, receiver profile inhomogeneities and T(1) saturation effects are included and allow the determination of water content with anatomical resolution and a precision >98%. The method was validated in phantom studies and was applied to the localized in vivo measurement of water content in a group of normal individuals and a patient with brain tumor. The results demonstrate that in vivo measurement of regional absolute water content is possible in clinically relevant measurement times with a statistical and systematic measurement error of <2%.
各种形式的脑水肿是许多疾病状态的伴随特征。虽然MRI可以显示脑水肿的局部发生情况，但绝对含水量的定量测定在脑水肿动态的客观评估和治疗效果监测中可能起着重要作用，而这方面的要求要高得多。我们提出了一种基于分别用于映射T(2)*和T(1)弛豫时间的两个快速多切片和多时间点序列QUTE和TAPIR相结合的局部和定量测量绝对含水量的方法。该方法纳入了对局部B(1)场校准错误、受试者与放置在视野中的参考探头之间的温度差异、接收器轮廓不均匀性以及T(1)饱和效应的校正，能够以解剖分辨率和大于98%的精度测定含水量。该方法在体模研究中得到验证，并应用于一组正常个体和一名脑肿瘤患者的局部体内含水量测量。结果表明，在临床相关测量时间内，可以在体内测量区域绝对含水量，统计和系统测量误差<2%。
