Son Jong Bum, Wright Steven M, Ji Jim X
Department of Electrical & Computer Engineering, Texas A&M University, College Station, Texas, USA.
Concepts Magn Reson Part B Magn Reson Eng. 2008 Aug;33B(3):152-162. doi: 10.1002/cmr.b.20120. Epub 2008 Jul 10.
This paper presents a method for high-speed water-fat imaging using Single-Echo Acquisition (SEA) with an array of 64 localized coil elements and single-point Dixon sequence. The method forms two-dimensional separate water and fat images from a single echo data. Specifically, a channel correlation and region-growing algorithm was developed to extract the phase information from the single echo data, eliminating the need for multiple data acquisition normally required for water/fat separation. Phantom studies on a 4.7 T scanner show that the method can handle large inter-channel and cross-channel phase variations, even at relative high data noise levels. Assume that the water and fat are spatially separated and they can be identified by the phase discontinuity caused by the chemical frequency shift, the new method can acquire separate water and fat images without reducing the high frame rates of the SEA imaging method. Although its capability is limited if there are large susceptibility artifacts, disconnected tissues, or pixels with mixed fat and water signals, the new method is potentially useful for dynamic imaging of small animals, where the SEA imaging can provide high imaging speed but may suffer from reduced contrast due to the strong fat signals at short repetition time.
本文提出了一种使用具有64个局部线圈元件阵列的单回波采集（SEA）和单点狄克逊序列进行高速水脂成像的方法。该方法从单个回波数据中形成二维独立的水和脂肪图像。具体而言，开发了一种通道相关性和区域生长算法，用于从单个回波数据中提取相位信息，从而无需通常用于水/脂分离的多次数据采集。在4.7 T扫描仪上进行的体模研究表明，即使在相对较高的数据噪声水平下，该方法也能处理较大的通道间和跨通道相位变化。假设水和脂肪在空间上是分离的，并且可以通过化学频率偏移引起的相位不连续性来识别，那么这种新方法可以在不降低SEA成像方法高帧率的情况下获取独立的水和脂肪图像。尽管如果存在大的磁化率伪影、分离的组织或具有混合脂肪和水信号的像素，其能力会受到限制，但这种新方法对于小动物的动态成像可能具有潜在的用途，在这种情况下，SEA成像可以提供高成像速度，但由于短重复时间下的强脂肪信号可能会导致对比度降低。
