Optimizing saturation-recovery measurements of the longitudinal relaxation rate under time constraints.
Optimizing saturation-recovery measurements of the longitudinal relaxation rate under time constraints.
复制标题
在时间限制下优化纵向松弛率的饱和恢复测量。
DOI：
10.1002/mrm.22111
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发表时间：
2009
影响因子：
3.3
通讯作者：
Zaharchuk,Greg
中科院分区：
文献类型：
--
作者：
Hsu,Jung-Jiin;Glover,GaryH;Zaharchuk,Greg
在恢复时间之和为1.5T1 ~ 3 T1（T1为纵向弛豫时间）的条件下，研究了使用两个和三个恢复时间的饱和-恢复方法。这些条件可以大大减少长T1核素的扫描时间，并使体液的纵向弛豫率R1（R1= 1/T1）映射在临床上可行。在恢复时间之和的各种约束条件下，进行了蒙特卡罗计算机模拟，以确定理想的恢复时间集。理想集被发现是近似不变的信噪比。对于三点法，其中两个恢复时间应设置为相同或大致相同，并应短于第三个。在恢复时间总和的共同约束下，三点法与两点法相比只能实现准确度和精密度的边际改善。采用快速自旋回波技术（XETA）对志愿者进行三维、高分辨率、全脑饱和恢复扫描，扫描时间为10 min，产生的脑脊液R1测量值（T1 ≤ 4 s）与计算机模拟和文献结果一致，这证明了将两点饱和恢复方法应用于长弛豫成分R1标测的临床可行性。Magn Reson Med，2009年。© 2009 Wiley利斯公司
The saturation–recovery method using two and three recovery times is studied for conditions in which the sum of recovery times is 1.5T1to 3T1, whereT1is the longitudinal relaxation time. These conditions can reduce scan time considerably for longT1species and make longitudinal relaxation rateR1(R1= 1/T1) mapping for body fluids clinically feasible. Monte Carlo computer simulation is carried out to determine the ideal set of recovery times under various constraints of the sum of recovery times. The ideal set is found to be approximately invariant to the signal‐to‐noise ratio. For the three‐point method, two of the recovery times should be set the same or approximately the same and should be shorter than the third one. Only marginal improvements in accuracy and precision can be achieved by the three‐point method over the two‐point method under a common constraint of the sum of recovery times. Three‐dimensional, high resolution, whole‐brain saturation–recovery scans on volunteers with a fast‐spin‐echo technique (XETA) and completed in a scan time of 10 min generatedR1measurements of cerebrospinal fluid (T1∼ 4 s) in agreement with the computer simulation and literature results, which demonstrates the clinical feasibility of applying the two‐point saturation–recovery method forR1mapping for long relaxation components. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.