Doganay Ozkan, Wade Trevor, Hegarty Elaine, McKenzie Charles, Schulte Rolf F, Santyr Giles E
Department of Medical Biophysics, Western University, London, ON, Canada.
Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada.
Magn Reson Med. 2016 Aug;76(2):566-76. doi: 10.1002/mrm.25911. Epub 2015 Aug 29.
To implement and optimize a single-shot spiral encoding strategy for rapid 2D IDEAL projection imaging of hyperpolarized (Hp) (129) Xe in the gas phase, and in the pulmonary tissue (PT) and red blood cells (RBCs) compartments of the rat lung, respectively.
A theoretical and experimental point spread function analysis was used to optimize the spiral k-space read-out time in a phantom. Hp (129) Xe IDEAL images from five healthy rats were used to: (i) optimize flip angles by a Bloch equation analysis using measured kinetics of gas exchange and (ii) investigate the feasibility of the approach to characterize the exchange of Hp (129) Xe.
A read-out time equal to approximately 1.8 × T2* was found to provide the best trade-off between spatial resolution and signal-to-noise ratio (SNR). Spiral IDEAL approaches that use the entire dissolved phase magnetization should give an SNR improvement of a factor of approximately three compared with Cartesian approaches with similar spatial resolution. The IDEAL strategy allowed imaging of gas, PT, and RBC compartments with sufficient SNR and temporal resolution to permit regional gas exchange measurements in healthy rats.
Single-shot spiral IDEAL imaging of gas, PT and RBC compartments and gas exchange is feasible in rat lung using Hp (129) Xe. Magn Reson Med 76:566-576, 2016. © 2015 Wiley Periodicals, Inc.
分别在气相以及大鼠肺组织（PT）和红细胞（RBC）隔室中，实现并优化单次螺旋编码策略，用于超极化（Hp）（129）Xe的快速二维IDEAL投影成像。
使用理论和实验点扩散函数分析来优化模型中的螺旋k空间读出时间。来自五只健康大鼠的Hp（129）Xe IDEAL图像用于：（i）通过使用测量的气体交换动力学的布洛赫方程分析来优化翻转角，以及（ii）研究表征Hp（129）Xe交换方法的可行性。
发现读出时间约等于1.8×T2*时，能在空间分辨率和信噪比（SNR）之间提供最佳权衡。与具有相似空间分辨率的笛卡尔方法相比，使用整个溶解相磁化的螺旋IDEAL方法的SNR应提高约三倍。IDEAL策略能够以足够的SNR和时间分辨率对气体、PT和RBC隔室进行成像，从而允许在健康大鼠中进行区域气体交换测量。
使用Hp（129）Xe对大鼠肺中的气体、PT和RBC隔室以及气体交换进行单次螺旋IDEAL成像是可行的。《磁共振医学》76:566 - 576，2016年。©2015威利期刊公司
