使用三维时间分辨螺旋广义自校准部分并行采集加速技术的自由呼吸肝脏灌注成像。
Free-breathing liver perfusion imaging using 3-dimensional through-time spiral generalized autocalibrating partially parallel acquisition acceleration.
作者信息
Chen Yong, Lee Gregory R, Wright Katherine L, Badve Chaitra, Nakamoto Dean, Yu Alice, Schluchter Mark D, Griswold Mark A, Seiberlich Nicole, Gulani Vikas
机构信息
From the *Department of Radiology, University Hospitals of Cleveland, †Department of Biomedical Engineering, and ‡Division of Biostatistics, Case Western Reserve University, Cleveland, OH.
出版信息
Invest Radiol. 2015 Jun;50(6):367-75. doi: 10.1097/RLI.0000000000000135.
OBJECTIVES
The goal of this study was to develop free-breathing high-spatiotemporal resolution dynamic contrast-enhanced liver magnetic resonance imaging using non-Cartesian parallel imaging acceleration, and quantitative liver perfusion mapping.
MATERIALS AND METHODS
This study was approved by the local institutional review board and written informed consent was obtained from all participants. Ten healthy subjects and 5 patients were scanned on a Siemens 3-T Skyra scanner. A stack-of-spirals trajectory was undersampled in-plane with a reduction factor of 6 and reconstructed using 3-dimensional (3D) through-time non-Cartesian generalized autocalibrating partially parallel acquisition. High-resolution 3D images were acquired with a true temporal resolution of 1.6 to 1.9 seconds while the subjects were breathing freely. A dual-input single-compartment model was used to retrieve liver perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging data, which were coregistered using an algorithm designed to reduce the effects of dynamic contrast changes on registration. Image quality evaluation was performed on spiral images and conventional images from 5 healthy subjects.
RESULTS
Images with a spatial resolution of 1.9 × 1.9 × 3 mm3 were obtained with whole-liver coverage. With an imaging speed of better than 2 s/vol, free-breathing scans were achieved and dynamic changes in enhancement were captured. The overall image quality of free-breathing spiral images was slightly lower than that of conventional long breath-hold Cartesian images, but it provided clinically acceptable or better image quality. The free-breathing 3D images were registered with almost no residual motion in liver tissue. After the registration, quantitative whole-liver 3D perfusion maps were obtained and the perfusion parameters are all in good agreement with the literature.
CONCLUSIONS
This high-spatiotemporal resolution free-breathing 3D liver imaging technique allows voxelwise quantification of liver perfusion.
目的
本研究的目的是利用非笛卡尔并行成像加速技术开发自由呼吸高时空分辨率动态对比增强肝脏磁共振成像以及定量肝脏灌注成像。
材料与方法
本研究经当地机构审查委员会批准，并获得所有参与者的书面知情同意。在西门子3-T Skyra扫描仪上对10名健康受试者和5名患者进行扫描。采用6倍的缩减因子对螺旋堆叠轨迹进行平面内欠采样，并使用三维（3D）时间分辨非笛卡尔广义自校准部分并行采集进行重建。在受试者自由呼吸时，以1.6至1.9秒的真实时间分辨率采集高分辨率3D图像。使用双输入单室模型从动态对比增强磁共振成像数据中获取肝脏灌注参数，这些数据使用一种旨在减少动态对比变化对配准影响的算法进行配准。对5名健康受试者的螺旋图像和传统图像进行图像质量评估。
结果
获得了空间分辨率为1.9×1.9×3 mm3且覆盖全肝的图像。成像速度优于2 s/vol，实现了自由呼吸扫描并捕捉到了增强的动态变化。自由呼吸螺旋图像的整体图像质量略低于传统长屏气笛卡尔图像，但提供了临床可接受或更好的图像质量。自由呼吸3D图像配准后肝脏组织几乎没有残余运动。配准后，获得了全肝定量3D灌注图，灌注参数与文献报道完全一致。
结论
这种高时空分辨率自由呼吸3D肝脏成像技术能够对肝脏灌注进行体素级定量分析。
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