Desmond Kimberly L, Ramsay Elizabeth A, Plewes Donald B
Division of Imaging Research, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, 2075 Bayview Avenue, Toronto, Canada.
J Magn Reson Imaging. 2007 Jun;25(6):1293-8. doi: 10.1002/jmri.20921.
To optimize a reordered k-space acquisition that applies intermittent fat saturation (FS) pulses to allow for a time-efficient reduction of fat signal in breast MR images, and compare it with an elliptic-centric biphasic FS method in terms of the degree of fat suppression and speed.
The behavior of the fat and water signals under the influence of the reordered sequence was characterized. This allowed us to optimize the flip angle and visualize the expected artifacts by deriving the point spread function (PSF) of the fat signal. We compared the two sequences by acquiring images with a varying number of FS pulses, with a corresponding difference in scan time. The quality of the images was assessed by comparison with images obtained with full fat suppression as measured by a root-mean-square (RMS) error metric.
The reordered sequence allowed for an approximately twofold reduction in error compared to the biphasic sequence for the same scan time. With the reordered sequence and optimized scan parameters, we were able to reduce the time spent on fat suppression by as much as 99% with no discernible reduction in image quality.
This method will allow robust fat suppression with virtually no extension in imaging time for dynamic contrast-enhanced (DCE)-MRI.
优化一种重新排序的k空间采集方法，该方法应用间歇性脂肪饱和（FS）脉冲，以便在乳腺磁共振成像中高效地减少脂肪信号，并在脂肪抑制程度和速度方面将其与椭圆中心双相FS方法进行比较。
对重新排序序列影响下的脂肪和水信号行为进行了表征。这使我们能够优化翻转角，并通过推导脂肪信号的点扩散函数（PSF）来可视化预期的伪影。我们通过采集具有不同数量FS脉冲的图像来比较这两种序列，扫描时间相应不同。通过与用均方根（RMS）误差度量测量的完全脂肪抑制获得的图像进行比较来评估图像质量。
在相同扫描时间下，与双相序列相比，重新排序的序列使误差降低了约两倍。通过重新排序的序列和优化的扫描参数，我们能够将脂肪抑制所花费的时间减少多达99%，而图像质量没有明显下降。
该方法将允许在动态对比增强（DCE）-MRI中实现强大的脂肪抑制，而几乎不会延长成像时间。
