Zhu Dan, Xu Feng, Liu Dapeng, Qin Qin
F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.
The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Magn Reson Med. 2025 Jun;93(6):2488-2498. doi: 10.1002/mrm.30439. Epub 2025 Jan 29.
The present work aims to evaluate the performance of three-dimensional (3D) single-shot stack-of-spirals turbo FLASH (SOS-TFL) acquisition for pseudo-continuous arterial spin labeling (PCASL) and velocity-selective ASL (VSASL)-based cerebral blood flow (CBF) mapping, as well as VSASL-based cerebral blood volume (CBV) mapping.
Digital phantom simulations were conducted for both multishot echo planar imaging and spiral trajectories with intershot signal fluctuations. PCASL-derived CBF (PCASL-CBF), VSASL-derived CBF (VSASL-CBF), and CBV (VSASL-CBV) were all acquired using 3D multishot gradient and spin-echo and SOS-TFL acquisitions following background suppression. Both simulation and in vivo images were compared between multishot and single-shot compressed sensing-regularized sensitivity encoding (CS-SENSE) reconstructions.
Artifacts were observed in both simulated multishot echo planar imaging and spiral readouts, as well as in in vivo multishot ASL perfusion images. A high correlation was found between the levels of signal fluctuations among interleaves and the severity of artifacts in both simulated and in vivo data. Image artifacts were more apparent in the inferior region of the brain, especially in CBF scans. These artifacts were effectively eliminated when single-shot CS-SENSE reconstruction was applied to the same data set.
ASL images obtained from 3D segmented gradient and spin-echo or SOS-TFL acquisitions can exhibit artifacts caused by signal fluctuations among different shots, which persist even after the application of background suppression pulses. In contrast, these artifacts were prevented when single-shot CS-SENSE reconstruction was applied to the same SOS-TFL data set.
本研究旨在评估三维（3D）单次激发螺旋堆叠式涡轮FLASH（SOS-TFL）采集技术在基于伪连续动脉自旋标记（PCASL）和速度选择性动脉自旋标记（VSASL）的脑血流（CBF）映射以及基于VSASL的脑血容量（CBV）映射中的性能。
针对多激发回波平面成像和具有激发间信号波动的螺旋轨迹进行了数字体模模拟。在背景抑制后，使用3D多激发梯度和自旋回波以及SOS-TFL采集技术获取PCASL衍生的CBF（PCASL-CBF）、VSASL衍生的CBF（VSASL-CBF）和CBV（VSASL-CBV）。对多激发和单次激发压缩感知正则化灵敏度编码（CS-SENSE）重建的模拟图像和体内图像进行了比较。
在模拟的多激发回波平面成像和螺旋读出以及体内多激发ASL灌注图像中均观察到伪影。在模拟数据和体内数据中，均发现不同激发间信号波动水平与伪影严重程度之间存在高度相关性。图像伪影在脑下部区域更为明显，尤其是在CBF扫描中。当对同一数据集应用单次激发CS-SENSE重建时，这些伪影得到了有效消除。
从3D分段梯度和自旋回波或SOS-TFL采集中获得的ASL图像可能会出现由不同激发间信号波动引起的伪影，即使应用背景抑制脉冲后这些伪影仍然存在。相比之下，当对相同的SOS-TFL数据集应用单次激发CS-SENSE重建时，可以防止这些伪影的出现。
