Pedersen Michael, Klarhöfer Markus, Christensen Søren, Ouallet Jean-Christophe, Ostergaard Leif, Dousset Vincent, Moonen Chrit
Department of Molecular and Functional Imaging (IMF) ERT CNRS, University Victor Segalen 2, Bordeaux, France.
J Magn Reson Imaging. 2004 Dec;20(6):930-40. doi: 10.1002/jmri.20206.
To evaluate the feasibility of using the rapid principles of echo shifting with a train of observations (PRESTO) sequence for measurements of cerebral hemodynamic parameters based on first pass of a contrast agent.
Simulations were performed to investigate potential resolution loss due to relaxation effects. Experimental evaluation was conducted in healthy monkey brains using PRESTO and echo-planar imaging (EPI).
For short echo trains, an insignificant contribution of the longitudinal and transversal relaxation rates to the signal amplitude in white matter and gray matter was found, whereas a contribution as large as 40% was found in large vessels. Simulations of the point spread function demonstrated that PRESTO, despite its shorter readout trains, only has a small advantage in terms of maintenance of image resolution during bolus passage compared to EPI as long as the EPI echo train can be kept similar to the T2* value at the top of the bolus. Experimental studies revealed that the PRESTO and EPI gray matter to white matter ratio were similar with respect to cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT).
The study showed that PRESTO and EPI led to comparable quantitative perfusion parameters.
评估基于造影剂首次通过利用带有一系列观测值的回波移位快速原理（PRESTO）序列测量脑血流动力学参数的可行性。
进行模拟以研究由于弛豫效应导致的潜在分辨率损失。在健康猴脑中使用PRESTO和回波平面成像（EPI）进行实验评估。
对于短回波链，发现纵向和横向弛豫率对白质和灰质信号幅度的贡献不显著，而在大血管中发现贡献高达40%。点扩散函数的模拟表明，尽管PRESTO的读出回波链较短，但只要EPI回波链能够保持与团注顶部的T2*值相似，在团注通过期间与EPI相比，PRESTO在维持图像分辨率方面仅具有小的优势。实验研究表明，就脑血流量（CBF）、脑血容量（CBV）和平均通过时间（MTT）而言，PRESTO和EPI的灰质与白质比率相似。
该研究表明，PRESTO和EPI产生的定量灌注参数相当。
