Andre Monteiro Paschoal1
1Institute of Physics, University of Campinas, Campinas, Brazil
Synopsis
Keywords: Contrast mechanisms: Perfusion, Image acquisition: Image processing
This talk aims to give an overview of the fundamental kinetic model to explain the ASL signal, the key bullets in the processing of the data to have a high-quality perfusion weighted image and quantitative perfusion-related parameters. The processing flow will continue through advanced steps that can be inserted into the pipeline to have a more accurate map or to obtain additional parameter maps. Target audience
Clinicians, physicists, scientists and/or radiographers who intend to understand how the ASL signal is modeled to obtain a high-quality perfusion imaging and how they can optimize their analysis model to make their protocol work. Overview
Arterial spin labeling is a non-invasive MR perfusion weighted imaging method that is being increasingly incorporated into clinical imaging protocols. However, despite some MR scanner vendors are working to provide a reliable ASL-CBF map onsite for diagnosis’ purposes, it still is recommended to have a more comprehensive processing pipeline offsite if we are looking for more accuracy in the CBF quantification or whether we are looking for additional information that requires more advanced models.
In this talk, we will begin with an overview of the general kinetic model used to explain the ASL signal and how it can vary for different labeling strategies. Next, we will go over recent efforts in standardizing the benchmarks for ASL processing and the ASL software inventory provided by the ISMRM Open Science Initiative for Perfusion Imaging (ISMRM OSIPI – www.osipi.org). Finally, we will briefly cover new advances to be attached in the processing pipelines to achieve more accurate perfusion maps (e.g., susceptibility distortion corrections, partial volume correction) as well as novel physiological parameters included in the kinetic model to infer other hemodynamic parameters (e.g., water exchange times).Specific Objectives
- Overview the theory of the ASL general kinetic model.
- Understanding the differences in the analysis when dealing with a different ASL labeling approach
- Recent OSIPI efforts to provide an ASL software inventory and identify important benchmarks to standardize the ASL data processing.
- Cover advanced modules that can be attached to the processing pipeline to improve the analysis.
- Exemplify novel physiological models to infer advanced hemodynamics information.
Acknowledgements
Sao Paulo Research Foundation (FAPESP)References
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Buxton R, et al., A general kinetic model for quantitative perfusion imaging with arterial spin labeling. Magnetic Resonance in Medicine 1998; 40(3):383–396.
Chappell MA, et al., Partial Volume Correction of Multiple Inversion Time Arterial Spin Labeling MRI Data. Magnetic Resonance in Medicine 2011; 65:1173–1183.
Woods et al., A general framework for optimizing arterial spin labeling MRI experiments. Magnetic Resonance in Medicine 2018; 81(4):2474-2488.
Pinto J, et al., Calibration of arterial spin labeling data — potential pitfalls in post‐processing. Magnetic Resonance in Medicine 2020; 83 (4),1222-1234.
ISMRM Open Science Initiative for Perfusion Imaging – ISMRM OSIPI (www.osipi.org); Task Force 1.1 ASL Software Inventory (https://osipi.org/task-force-1-1/) and Task Force 6.1 ASL Challenges (https://osipi.org/task-force-6-1/).