Vascular Imaging Lab, Department of Radiology, University of Washington, Seattle, WA, United States; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, United States.
Vascular Imaging Lab, Department of Radiology, University of Washington, Seattle, WA, United States; BioMolecular Imaging Center, Department of Radiology, University of Washington, Seattle, WA, United States.
Magn Reson Imaging. 2021 Jun;79:20-27. doi: 10.1016/j.mri.2021.02.012. Epub 2021 Mar 6.
To explore feasibility of using the vessel length on time-of-flight (TOF) or simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) MRA as an imaging biomarker for brain blood flow, by using arterial spin labeling (ASL) perfusion imaging and 3D phase contrast (PC) quantitative flow imaging as references.
In a population of thirty subjects with carotid atherosclerotic disease, the visible intracranial arteries on TOF and SNAP were semi-automatically traced and the total length of the distal segments was calculated with a dedicated software named iCafe. ASL blood flow was calculated automatically using the recommended hemodynamic model. PC blood flow was obtained by generating cross-sectional arterial images and semi-automatically drawing the lumen contours. Pearson correlation coefficients were used to assess the associations between the different whole-brain or hemispheric blood flow measurements.
Under the imaging protocol used in this study, TOF vessel length was larger than SNAP vessel length (P < 0.001). Both whole-brain TOF and SNAP vessel length showed a correlation with whole brain ASL and 3D PC blood flow measurements, and the correlation coefficients were higher for SNAP vessel length (TOF vs ASL: R = 0.554, P = 0.002; SNAP vs ASL: R = 0.711, P < 0.001; TOF vs 3D PC: R = 0.358, P = 0.052; SNAP vs 3D PC: R = 0.425, P = 0.019). Similar correlation results were observed for the hemispheric measurements. Hemispheric asymmetry index of SNAP vessel length also showed a significant correlation with hemispheric asymmetry index of ASL cerebral blood flow (R = 0.770, P < 0.001).
The results suggest that length of the visible intracranial arteries on TOF or SNAP MRA can serve as a potential imaging marker for brain blood flow.
通过动脉自旋标记（ASL）灌注成像和 3D 相位对比（PC）定量血流成像作为参考，探讨基于时间飞越（TOF）或同时非对比血管成像和斑块内出血（SNAP）MRA 的血管长度作为脑血流成像生物标志物的可行性。
在 30 例颈动脉粥样硬化患者的人群中，采用专用软件 iCafe 半自动追踪 TOF 和 SNAP 上可见的颅内动脉，并计算远端节段的总长度。ASL 血流自动采用推荐的血流动力学模型计算。PC 血流通过生成横截面动脉图像并半自动绘制管腔轮廓获得。采用 Pearson 相关系数评估不同全脑或半球血流测量值之间的相关性。
在本研究使用的成像方案下，TOF 血管长度大于 SNAP 血管长度（P<0.001）。全脑 TOF 和 SNAP 血管长度与全脑 ASL 和 3D PC 血流测量值均相关，且 SNAP 血管长度的相关系数更高（TOF 与 ASL：R=0.554，P=0.002；SNAP 与 ASL：R=0.711，P<0.001；TOF 与 3D PC：R=0.358，P=0.052；SNAP 与 3D PC：R=0.425，P=0.019）。半球测量值也观察到类似的相关性结果。SNAP 血管长度的半球不对称指数也与 ASL 脑血流的半球不对称指数显著相关（R=0.770，P<0.001）。
结果表明，TOF 或 SNAP MRA 上可见颅内动脉的长度可以作为脑血流的潜在成像标志物。
