Department of Electrical Computer Engineering University of Illinois at Urbana-Champaign Urbana Illinois, USA.
Magn Reson Med. 2010 Oct;64(4):1162-70. doi: 10.1002/mrm.22500.
Dynamic contrast-enhanced MRI (or DCE-MRI) is a useful tool for measuring blood flow and perfusion, and it has found use in the study of pulmonary perfusion in animal models. However, DCE-MRI experiments are difficult in small animals such as rats. A recently developed method known as Interleaved Radial Imaging and Sliding window-keyhole (IRIS) addresses this problem by using a data acquisition scheme that covers (k,t)-space with data acquired from multiple bolus injections of a contrast agent. However, the temporal resolution of IRIS is limited by the effects of temporal averaging inherent in the sliding window and keyhole operations. This article describes a new method to cover (k,t)-space based on the theory of partially separable functions (PSF). Specifically, a sparse sampling of (k,t)-space is performed to acquire two data sets, one with high-temporal resolution and the other with extended k-space coverage. The high-temporal resolution training data are used to determine the temporal basis functions of the PSF model, whereas the other data set is used to determine the spatial variations of the model. The proposed method was validated by simulations and demonstrated by an experimental study. In this particular study, the proposed method achieved a temporal resolution of 32 msec.
动态对比增强磁共振成像（DCE-MRI）是一种测量血流和灌注的有用工具，它已在动物模型的肺灌注研究中得到应用。然而，在大鼠等小动物中进行 DCE-MRI 实验较为困难。最近开发的一种方法称为交错径向成像和滑动窗口-钥匙孔（IRIS），它通过使用一种数据采集方案来解决这个问题，该方案使用来自对比剂多次团注的采集数据覆盖（k，t）-空间。然而，IRIS 的时间分辨率受到滑动窗口和钥匙孔操作中固有的时间平均效应的限制。本文描述了一种基于部分可分离函数（PSF）理论的新的覆盖（k，t）-空间的方法。具体来说，通过稀疏采样（k，t）-空间来获取两个数据集，一个具有高时间分辨率，另一个具有扩展的 k-空间覆盖范围。高时间分辨率的训练数据用于确定 PSF 模型的时间基函数，而另一个数据集用于确定模型的空间变化。通过模拟验证和实验研究验证了所提出的方法。在这项特定的研究中，所提出的方法实现了 32 毫秒的时间分辨率。
