Murase Kenya
Department of Medical Physics and Engineering, Faculty of Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan.
Magn Reson Med. 2004 Apr;51(4):858-62. doi: 10.1002/mrm.20022.
It has become increasingly important to quantitatively estimate tissue physiological parameters such as perfusion, capillary permeability, and the volume of extravascular-extracellular space (EES) using T(1)-weighted dynamic contrast-enhanced MRI (DCE-MRI). A linear equation was derived by integrating the differential equation describing the kinetic behavior of contrast agent (CA) in tissue, from which K(1) (rate constant for the transfer of CA from plasma to EES), k(2) (rate constant for the transfer from EES to plasma), and V(p) (plasma volume) can be easily obtained by the linear least-squares (LLSQ) method. The usefulness of this method was investigated by means of computer simulations, in comparison with the nonlinear least-squares (NLSQ) method. The new method calculated the above parameters faster than the NLSQ method by a factor of approximately 6, and estimated them more accurately than the NLSQ method at a signal-to-noise ratio (SNR) of < approximately 10. This method will be useful for generating functional images of K(1), k(2), and V(p) from DCE-MRI data.
使用T(1)加权动态对比增强磁共振成像（DCE-MRI）定量估计组织生理参数，如灌注、毛细血管通透性和血管外细胞外间隙（EES）体积，变得越来越重要。通过对描述组织中对比剂（CA）动力学行为的微分方程进行积分，推导出一个线性方程，通过线性最小二乘法（LLSQ）可以轻松获得K(1)（CA从血浆转移到EES的速率常数）、k(2)（从EES转移到血浆的速率常数）和V(p)（血浆体积）。与非线性最小二乘法（NLSQ）相比，通过计算机模拟研究了该方法的实用性。新方法计算上述参数的速度比NLSQ方法快约6倍，并且在信噪比（SNR）<约10时比NLSQ方法估计得更准确。该方法将有助于从DCE-MRI数据生成K(1)、k(2)和V(p)的功能图像。
