Optimization of pseudo-continuous arterial spin labeling using off-resonance compensation strategies at 7T.
Optimization of pseudo-continuous arterial spin labeling using off-resonance compensation strategies at 7T.
复制标题
DOI：
10.1002/mrm.29070
复制
发表时间：
2022-04
影响因子：
3.3
通讯作者：
Talagala SL
中科院分区：
文献类型：
--
作者：
Saïb G;Koretsky AP;Talagala SL
伪连续动脉自旋标记（PCASL）对非共振效应（Δ B 0）的敏感性是超高场（≥ 7 T）的主要限制。本研究的目的是评估不同PCASL Δ B 0补偿方法在7 T下的有效性，并测量偏离共振校正的标记效率。通过在PCASL RF脉冲序列中增加额外的RF相位增量和横向梯度信号，可以补偿由供血动脉处的Δ B 0引起的相位偏移误差。在7 T下比较了平均场校正（AVGcor）、基于血管特定场图的校正（FMcor）和基于血管特定预扫描的校正（PScor）的有效性。校正后，在标记位置下游的供血动脉中直接测量PCASL标记效率。在非共振校正后，灌注信号在整个大脑中更加均匀。与未经校正的采集相比，使用AVGcor、FMcor和PScor的全脑平均灌注信号分别增加了2.4、2.5和2.1倍。当使用0.25mT/m的平均梯度（Gmean）时，在0.70μT的平均B1（B1 mean）下，经非共振校正，最大标记效率约为0.68。预扫描或场图可用于校正非共振效应并在7 T下检索良好的脑灌注信号。尽管这三种方法在本研究中表现良好，但FMcor可能更适合患者研究，因为它考虑了血管特异性Δ B 0变化。通过使用先进的硬件和软件优化标记效率，同时满足SAR约束，可以进一步提高图像质量。
The sensitivity of pseudo-continuous arterial spin labeling (PCASL) to off-resonance effects (ΔB0) is a major limitation at ultra-high field (≥7T). The aim of this study was to assess the effectiveness of different PCASL ΔB0 compensation methods at 7T and measure the labeling efficiency with off-resonance correction. Phase offset errors induced by ΔB0 at the feeding arteries can be compensated by adding an extra RF phase increment and transverse gradient blips into the PCASL RF pulse train. The effectiveness of an average field correction (AVGcor), a vessel-specific field-map-based correction (FMcor) and a vessel-specific prescan-based correction (PScor) were compared at 7T. After correction, the PCASL labeling efficiency was directly measured in feeding arteries downstream from the labeling location. The perfusion signal was more uniform throughout the brain after off-resonance correction. Whole-brain average perfusion signal increased by a factor of 2.4, 2.5 and 2.1 respectively with AVGcor, FMcor and PScor compared to acquisitions without correction. With off-resonance correction, the maximum labeling efficiency was ~0.68 at mean B1 (B1mean) of 0.70μT when using a mean gradient (Gmean) of 0.25mT/m. Either a prescan or a field map can be used to correct for off-resonance effects and retrieve a good brain perfusion signal at 7T. Although the three methods performed well in this study, FMcor may be better suited for patient studies because it accounted for vessel-specific ΔB0 variations. Further improvements in image quality will be possible by optimizing the labeling efficiency with advanced hardware and software while satisfying SAR-constraints.
登录
查看更多内容
影响因子：
3.3
作者：
Chung, Sohae;Kim, Daniel;Breton, Elodie;Axel, Leon
通讯作者：
Axel, Leon
影响因子：
3.3
作者：
DETRE, JA;LEIGH, JS;KORETSKY, AP
通讯作者：
KORETSKY, AP
DOI：
10.1097/00004647-199611000-00019
发表时间：
1996-11-01
影响因子：
6.3
作者：
Alsop, DC;Detre, JA
通讯作者：
Detre, JA
影响因子：
3.3
作者：
Rooney, William D.;Johnson, Glyn;Springer, Charles S., Jr.
通讯作者：
Springer, Charles S., Jr.
影响因子：
3.3
作者：
Meixner, Christian R.;Eisen, Christian K.;Nagel, Armin M.
通讯作者：
Nagel, Armin M.