Plein Sven, Ryf Salome, Schwitter Juerg, Radjenovic Aleksandra, Boesiger Peter, Kozerke Sebastian
Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
Magn Reson Med. 2007 Oct;58(4):777-85. doi: 10.1002/mrm.21381.
In the k-t sensitivity encoding (k-t SENSE) method spatiotemporal data correlations are exploited to accelerate data acquisition in dynamic MRI studies. The present study demonstrates the feasibility of applying k-t SENSE to contrast-enhanced myocardial perfusion MRI and using the speed-up to increase spatial resolution. At a net acceleration factor of 3.9 (k-t factor of 5 with 11 training profiles) accurate representations of dynamic signal intensity (SI) changes were achieved in computer simulations. In vivo, 5x k-t SENSE was compared with 2x SENSE (identical acquisition parameters except for in-plane spatial resolution = 1.48 x 1.48 mm(2) vs. 2.64 x 2.64 mm(2), respectively). In 10 volunteers no differences in myocardial SI profiles were found (relative peak enhancement = 151% vs. 149.7%, maximal upslope = 12.9%/s vs. 13.3%/s for 2x SENSE and 5x k-t SENSE, respectively, all P > 0.05). Overall image quality was similar, but endocardial dark rim artifacts were reduced with k-t SENSE. Signal-to-noise ratio (SNR) in the myocardium was greater with 5x k-t SENSE by a factor of 1.36 +/- 0.23 at peak contrast enhancement with the relative yield decreasing with increasing dynamics in the object in accordance to theory. Higher nominal acceleration factors of up to 10-fold were shown to be feasible in computer simulations and in vivo.
在k-t灵敏度编码(k-t SENSE)方法中,利用时空数据相关性来加速动态磁共振成像(MRI)研究中的数据采集。本研究证明了将k-t SENSE应用于对比增强心肌灌注MRI以及利用加速来提高空间分辨率的可行性。在净加速因子为3.9(k-t因子为5,有11个训练轮廓)时,在计算机模拟中实现了动态信号强度(SI)变化的准确表示。在体内,将5倍k-t SENSE与2倍SENSE进行比较(除面内空间分辨率分别为1.48×1.48 mm²和2.64×2.64 mm²外,采集参数相同)。在10名志愿者中,未发现心肌SI曲线有差异(2倍SENSE和5倍k-t SENSE的相对峰值增强分别为151%和149.7%,最大上升斜率分别为12.9%/秒和13.3%/秒,所有P>0.05)。整体图像质量相似,但k-t SENSE减少了心内膜暗边伪影。在峰值对比增强时,5倍k-t SENSE使心肌中的信噪比(SNR)提高了1.36±0.23倍,相对产量根据理论随着物体动态性增加而降低。在计算机模拟和体内研究中均显示,高达10倍的更高标称加速因子是可行的。