基于同时多层激发和并行成像的心脏磁共振电影成像

Accelerated Cardiac CINE Imaging with CAIPIRINHA and Partial Parallel Acquisition

磁共振成像(MRI)无创无害、对比度多、可以任意剖面成像的特点特别适合用于心脏成像,却因扫描时间长限制了其在临床上的应用.为了解决心脏磁共振电影成像屏气扫描时间过长的问题,该文提出了一种基于同时多层激发的多倍加速心脏磁共振电影成像及其影像重建的方法,该方法将相位调制多层激发(CAIPIRINHA)技术与并行加速(PPA)技术相结合,运用到分段采集心脏电影成像序列中,实现了在相位编码方向和选层方向的四倍加速,并使用改进的SENSE/GRAPPA算法对图像进行重建.分别在水模以及人体上进行了实验,将加速序列图像与不加速序列图像进行对比,结果验证了重建算法的有效性,表明该方法可以在保障图像质量以及准确测量心脏功能的前提下成倍节省扫描时间.

Cardiac magnetic resonance imaging(CMRI)is a non-invasive technique that features multi-contrast and allowsimaging at arbitrary orientations.However,the clinical applications of cardiac MRI are limited,mainly due to its long scantime.To speed up cardiac CINE imaging,a multi-fold accelerated cardiac CINE imaging method based on simultaneousmulti-slice imaging and reconstruction technique was proposed.By combining the controlled aliasing in parallel imagingresults in higher acceleration(CAIPIRINHA)technique and a partial parallel acquisition(PPA)scheme,a four-foldacceleration(i.e.,2-fold along the phase encoding direction and2-fold along the slice encoding direction)was achieved.The proposed technique was tested and verified on phantoms and human subjects using an improved image reconstructionmethod SENSE/GRAPPA.Results demonstrated that the proposed method is effective in reducing cardiac CINE scan time,while preserving image quality and accuracy of cardiac function assessment.