Liu Dexiang, Xu Feng, Lin Doris D, van Zijl Peter C M, Qin Qin
Department of Radiology, Panyu District Central Hospital, Guangzhou, Guangdong Province, China.
The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Magn Reson Med. 2017 Jan;77(1):92-101. doi: 10.1002/mrm.26515. Epub 2016 Oct 31.
To develop a non-contrast-enhanced MRI method for cerebral blood volume (CBV) mapping using velocity-selective (VS) pulse trains.
The new pulse sequence applied velocity-sensitive gradient waveforms in the VS label modules and velocity-compensated ones in the control scans. Sensitivities to the gradient imperfections (e.g., eddy currents) were evaluated through phantom studies. CBV quantification procedures based on simulated labeling efficiencies for arteriolar, capillary, and venular blood as a function of cutoff velocity (Vc) are presented. Experiments were conducted on healthy volunteers at 3T to examine the effects of unbalanced diffusion weighting, cerebrospinal (CSF) contamination and variation of Vc.
Phantom results of the used VS pulse trains demonstrated robustness to eddy currents. The mean CBV values of gray matter and white matter for the experiments using Vc = 3.5 mm/s and velocity-compensated control with CSF-nulling were 5.1 ± 0.6 mL/100 g and 2.4 ± 0.2 mL/100 g, respectively, which were 23% and 32% lower than results from the experiment with velocity-insensitive control, corresponding to 29% and 25% lower in averaged temporal signal-to-noise ratio values.
A novel technique using VS pulse trains was demonstrated for CBV mapping. The results were both qualitatively and quantitatively close to those from existing methods. Magn Reson Med 77:92-101, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
开发一种使用速度选择（VS）脉冲序列进行脑血容量（CBV）映射的非对比增强MRI方法。
新的脉冲序列在VS标记模块中应用了速度敏感梯度波形，在对照扫描中应用了速度补偿波形。通过体模研究评估了对梯度缺陷（如涡流）的敏感性。提出了基于模拟标记效率的CBV量化程序，该效率是动脉、毛细血管和静脉血的截止速度（Vc）的函数。在3T场强下对健康志愿者进行了实验，以研究不平衡扩散加权、脑脊液（CSF）污染和Vc变化的影响。
所使用的VS脉冲序列的体模结果表明对涡流具有鲁棒性。使用Vc = 3.5 mm/s和脑脊液抑制的速度补偿对照进行实验时，灰质和白质的平均CBV值分别为5.1±0.6 mL/100 g和2.4±0.2 mL/100 g，比使用速度不敏感对照的实验结果分别低23%和32%，对应平均时间信噪比降低29%和25%。
证明了一种使用VS脉冲序列进行CBV映射的新技术。结果在定性和定量上都与现有方法相近。Magn Reson Med 77:92 - 101, 2017. © 2016国际磁共振医学学会。
