Theory
ASL Perfusion MRI：是利用血液中的水 作为内源失踪剂，来探测CBF（cerebral blood flow）的。
ASL ASL Perfusion MRI 与BOLD MRI的比较
ASL ASL Perfusion MRI 与BOLD MRI的比较
ASL ASL Perfusion MRI 与BOLD MRI的比较
Radiology
Detre, J. A., and Alsop, D. C. 1999.
Perfusion fMRI with arterial spin labeling.
Functional MRI
History
Jiongjiong Wang, Ph.D. Research Assistant Professor of Radiology and Neurology University of Pennsylvania
动脉自旋标记灌注功能磁共振成像
Arterial Spin Labeling Perfusion fMRI
History
Alsop, D. C., and Detre, J. A. 1998.
Multisection cerebral blood flow MR imaging with continuous arterial spin labeling.
ASL Perfusion MRI 与BOLD MRI的比较
ASL Perfusion MRI 与Nuclear Imaging的比较
• • • • • SNR 高 分辨率高 安全性好 速度快 不同任务可以在一次试验内完成。
Stress 试验结果
Stress 试验结果
Conclusion
• ASL Perfusion MRI 相对于BOLD MRI更 合适做 诸如情绪变化，学习过程等；而 BOLD MRI更适合做认知或感觉运动刺激 等。 • 与SPECT成像同属灌注成像；但比 SPECT成像质量更高，时间性更好。
由刺激引起人的BOLD信号时程，即时 程脉冲反应函数，通常被称为血液动 力学响应函数(HRF)。
Theory
Theory
BOLD fMRI的缺陷： The other end of the frequency spectrum slow “drifts” in fMRI signal confound comparisons of activity spaced much more than a minute apart. Experiments with longer blocks (lower task frequencies) are most affected。。。
Theory
• Perfusion 可定义为血液向组织转运的稳 定状态。 • 常将各种灌注测量方法分为两类
– Exo-genous Contrast Tracer – Indogenous Contrast Tracer
水分子的微量运动会造成NMR信号的相移，用专门设计的相位 敏感RI:
BOLD（blood oxygen level-dependent） 是合氧血红蛋白和脱氧血红蛋白的磁化率有差异，神经 活动引起的血流有变化、血氧浓度及代谢率有变化的综
合机制。
Theory
BOLD fMRI 广泛应用于任务激活成像 研究中，特别是采用ER试验设计的个 体认知和感觉试验中。
History
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1. J. Wang, D.J. Licht (2006) Pediatric perfusion MRI with arterial spin labeling Neuroimaging Clinics of North America 16: 149-167 2. J. Wang, H. Rao, G.S. Wetmore, P.M. Furlan, M. Korczykowski, D.F. Dinges, J.A. Detre (2005) Perfusion fMRI reveals cerebral blood flow pattern under psychological stress. Proceedings of the National Academy of Sciences of U.S.A. 102:17804-17809. 3. J.Wang, Z. Wang, G.K. Aguirre, J.A. Detre (2005) To smooth or not to smooth? ? ROC analysis of perfusion fMRI data. Magn. Reson. Imag. 23: 75-81 4. J. Wang, Y. Zhang, R.L. Wolf, A.C. Roc, D.C. Alsop and J.A. Detre (2005) Amplitude modulated continuous arterial spin labeling perfusion MRI with single coil at 3.0 Tesla. Radiology 235:218-228 5. J. Wang, D.J. Licht, G.H. Jahng, C.S. Liu, J.T. Rabin, J. Haselgrove, R.A. Zimmerman and J.A. Detre (2003) Pediatric perfusion imaging using pulsed arterial spin labeling. J. Magn. Reson. Img. 18(4):404-413. 6. J. Wang, G.K. Aguirre, D.Y. Kimberg, J.A. Detre (2003) Empirical analyses of nullhypothesis perfusion fMRI data at 1.5 and 4.0 Tesla. Neuroimage. 19(4):1449-1462. 7. J. Wang, D.C. Alsop, H.K. Song, J.A. Maldijian, K. Tang, A.E. Salvucci, J.A. Detre. (2003) Transit time imaging with flow encoding arterial spin tagging (FEAST). Magn. Reson. Med. 50(3):599-607. 8. J. Wang, G.K. Aguirre, D.Y. Kimberg, A.C. Roc, L. Li, J.A. Detre (2003) Arterial spin labeling perfusion fMRI with very low task frequency. Magn. Reson. Med. 49: 796-802. 9. J. Wang, D.C. Alsop, L. Li, J. Listerud, J.B. Gonzalez-At, M.D. Schnall and J.A. Detre (2002) Comparison of Quantitative Perfusion Imaging using Arterial Spin Labeling at 1.5 and 4.0 Tesla. Magn. Reson. Med. 48:242-254.