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fMRI: Biological Basis and Experiment Design Lecture 15: CBF and Localization II

fMRI: Biological Basis and Experiment Design Lecture 15: CBF and Localization II. CBF techniques Big veins and big voxels. 1 light year = 5,913,000,000,000 miles?. Harrison, Harel et al., Cerebral Cortex 12:225 (2002). 100  m. Perfusion techniques.

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fMRI: Biological Basis and Experiment Design Lecture 15: CBF and Localization II

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  1. fMRI: Biological Basis and Experiment DesignLecture 15: CBF and Localization II • CBF techniques • Big veins and big voxels 1 light year = 5,913,000,000,000 miles?

  2. Harrison, Harel et al., Cerebral Cortex 12:225 (2002) 100m

  3. Perfusion techniques • FAIR – Flow-sensitive Alternating Inverstion Recovery • MOTIVE – MOdulation of TIssue and VEssel signal • QUIPSS – QUantitative Imaging of Perfusion using a Single Subtraction • QUIPSS-II – QUIPSS ... 2nd version • CASL – Continuous Arterial Spin Labeling • PASL – Pulsed Arterial Spin Labeling

  4. Perfusion (ASL) – general idea • Water in blood is used as a tracer • Two images are measured • With inversion of incoming blood • Longitudinal magnetization of incoming blood is inverted, and subtracts from total voxel signal • Without inversion of incoming blood • Difference image indicates

  5. CASL vs. PASL • Continuous ASL • long pulse is applied to neck arteries, so all blood coming into the head is inverted • After an appropriate delay (~1 – 2s) for that blood to get to the volume of interest, image is acquired • Reference image is taken without inversion pulse • Subtraction provides perfusion map • Pulsed ASL • Inversion is done in slab surrounding slices of interest • The rest is the same ...

  6. Low res SE High res SE

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