Ji Yang, Lu Dongshuang, Jiang Yinghua, Wang Xiaoying, Meng Yuguang, Sun Phillip Zhe
Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA.
Clinical Neuroscience Research Center, Department of Neurosurgery, Tulane University School of Medicine, New Orleans, Louisiana, USA.
Magn Reson Med. 2021 Mar;85(3):1571-1580. doi: 10.1002/mrm.28510. Epub 2020 Sep 24.
To develop fast multi-slice apparent T (T ) mapping for accurate cerebral blood flow (CBF) quantification with arterial spin labeling (ASL) MRI.
Fast multi-slice T was measured using a modified inversion recovery echo planar imaging (EPI) sequence with simultaneous application of ASL tagging radiofrequency (RF) and gradient pulses. The fast multi-slice T measurement was compared with the single-slice T imaging approach, repeated per slice. CBF was assessed in healthy adult Wistar rats (N = 5) and rats with acute stroke 24 hours after a transient middle cerebral artery occlusion (N = 5).
The fast multi-slice T measurement was in good agreement with that of a single-slice T imaging approach (Lin's concordance correlation coefficient = 0.92). CBF calculated using T reasonably accounted for the finite labeling RF duration, whereas the routine T -normalized ASL MRI underestimated the CBF, particularly at short labeling durations. In acute stroke rats, the labeling time and the CBF difference (ΔCBF) between the contralateral normal area and the ischemic lesion were significantly correlated when using T -normalized perfusion calculation (R = 0.844, P = .035). In comparison, T -normalized ΔCBF had little labeling time dependence based on the linear regression equation of ΔCBF = -0.0247*τ + 1.579 mL/g/min (R = -0.352, P = .494).
Our study found fast multi-slice T imaging improves the accuracy and reproducibility of CBF measurement.
开发快速多层面表观T（T*）映射技术，用于通过动脉自旋标记（ASL）磁共振成像（MRI）准确量化脑血流量（CBF）。
使用改良的反转恢复回波平面成像（EPI）序列测量快速多层面T*，同时施加ASL标记射频（RF）和梯度脉冲。将快速多层面T测量结果与单层面T成像方法进行比较，后者对每个层面重复测量。在健康成年Wistar大鼠（N = 5）和短暂性大脑中动脉闭塞24小时后的急性中风大鼠（N = 5）中评估CBF。
快速多层面T测量结果与单层面T成像方法高度一致（林氏一致性相关系数 = 0.92）。使用T计算的CBF合理考虑了有限的标记RF持续时间，而常规的T归一化ASL MRI低估了CBF，尤其是在短标记持续时间时。在急性中风大鼠中，使用T归一化灌注计算时，标记时间与对侧正常区域和缺血性病变之间的CBF差异（ΔCBF）显著相关（R = 0.844，P = 0.035）。相比之下，基于ΔCBF = -0.0247τ + 1.579 mL/g/min的线性回归方程，T*归一化的ΔCBF对标记时间的依赖性较小（R = -0.352，P = 0.494）。
我们的研究发现快速多层面T*成像提高了CBF测量的准确性和可重复性。
