3D hyperpolarized he-3 MRI of ventilation using a multi-echo projection acquisition
3D hyperpolarized he-3 MRI of ventilation using a multi-echo projection acquisition
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DOI：
10.1002/mrm.21437
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发表时间：
2008-05-01
影响因子：
3.3
通讯作者：
Fain, Sean B.
中科院分区：
文献类型：
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作者：
Holmes, James H.;O'Halloran, Rafael L.;Fain, Sean B.
介绍了一种使用吸入超极化（HP）He-3 MR进行全肺高分辨率3D成像的方法，该方法具有多个半回波径向轨迹，可以通过欠采样加速成像。多个半回波径向轨迹可用于通过增加HIP He-3肺成像的每单位时间采集的数据量来降低欠采样3D投影重建（PR）成像的伪影水平。使用模拟评估了使用多个半回波轨迹的屏气He-3 MRI的点扩散函数（PSF），以预测T-2* 和气体扩散对图像质量的影响。PSF模拟的结果与志愿者研究中的成像结果一致，显示图像质量随着回波数量的增加而提高，使用最多8个半回波。所示的8半回波采集，以适应失去屏气短至6秒，使用回顾性重建在降低的分辨率，也允许减少屏气时间相比，等效的笛卡尔轨迹。此外，初步结果从三维动态吸气-呼气演习证明使用8半回波轨迹。结果表明，首次使用HIP He-3 MR对人体通气和呼吸动力学进行高分辨率3D PR成像。
A method is presented for high-resolution 3D imaging of the whole lung using inhaled hyperpolarized (HP) He-3 MR with multiple half-echo radial trajectories that can accelerate imaging through undersampling. A multiple half-echo radial trajectory can be used to reduce the level of artifact for under-sampled 3D projection reconstruction (PR) imaging by increasing the amount of data acquired per unit time for HIP He-3 lung imaging. The point spread functions (PSFs) for breath-held He-3 MRI using multiple half-echo trajectories were evaluated using simulations to predict the effects of T-2* and gas diffusion on image quality. Results from PSF simulations were consistent with imaging results in volunteer studies showing improved image quality with increasing number of echoes using up to 8 half-echoes. The 8-half-echo acquisition is shown to accommodate lost breath-holds as short as 6 sec using a retrospective reconstruction at reduced resolution and also to allow reduced breath-hold time compared with an equivalent Cartesian trajectory. Furthermore, preliminary results from a 3D dynamic inhalation-exhalation maneuver are demonstrated using the 8-half-echo trajectory. Results demonstrate the first highresolution 3D PR imaging of ventilation and respiratory dynamics in humans using HIP He-3 MR.