Adluru Ganesh, Awate Suyash P, Tasdizen Tolga, Whitaker Ross T, Dibella Edward V R
Electrical and Computer Engineering Department, University of Utah, Salt Lake City, UT, USA.
Magn Reson Med. 2007 Jun;57(6):1027-36. doi: 10.1002/mrm.21248.
Dynamic contrast-enhanced (DCE) MRI is a powerful technique to probe an area of interest in the body. Here a temporally constrained reconstruction (TCR) technique that requires less k-space data over time to obtain good-quality reconstructed images is proposed. This approach can be used to improve the spatial or temporal resolution, or increase the coverage of the object of interest. The method jointly reconstructs the space-time data iteratively with a temporal constraint in order to resolve aliasing. The method was implemented and its feasibility tested on DCE myocardial perfusion data with little or no motion. The results obtained from sparse k-space data using the TCR method were compared with results obtained with a sliding-window (SW) method and from full data using the standard inverse Fourier transform (IFT) reconstruction. Acceleration factors of 5 (R = 5) were achieved without a significant loss in image quality. Mean improvements of 28 +/- 4% in the signal-to-noise ratio (SNR) and 14 +/- 4% in the contrast-to-noise ratio (CNR) were observed in the images reconstructed using the TCR method on sparse data (R = 5) compared to the standard IFT reconstructions from full data for the perfusion datasets. The method has the potential to improve dynamic myocardial perfusion imaging and also to reconstruct other sparse dynamic MR acquisitions.
动态对比增强（DCE）磁共振成像（MRI）是一种用于探测身体感兴趣区域的强大技术。本文提出了一种时间约束重建（TCR）技术，该技术随着时间推移所需的k空间数据更少，就能获得高质量的重建图像。这种方法可用于提高空间或时间分辨率，或增加感兴趣对象的覆盖范围。该方法通过在时间上施加约束，对时空数据进行联合迭代重建，以解决混叠问题。该方法已在几乎无运动或无运动的DCE心肌灌注数据上实现并测试了其可行性。将使用TCR方法从稀疏k空间数据中获得的结果，与使用滑动窗口（SW）方法获得的结果以及使用标准傅里叶逆变换（IFT）重建从完整数据中获得的结果进行了比较。实现了5倍（R = 5）的加速因子，且图像质量没有显著损失。与灌注数据集完整数据的标准IFT重建相比，在使用TCR方法对稀疏数据（R = 5）重建的图像中，观察到信噪比（SNR）平均提高了28±4%，对比噪声比（CNR）平均提高了14±4%。该方法有潜力改善动态心肌灌注成像，并可用于重建其他稀疏动态磁共振采集数据。
