Rapid and Quantitative Chemical Exchange Saturation Transfer (CEST) Imaging with Magnetic Resonance Fingerprinting (MRF)
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| Autores principales: | , , , , |
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| Formato: | Preprint |
| Publicado: |
2017
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| _version_ | 1866909257645948928 |
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| author | Cohen, Ouri Huang, Shuning McMahon, Michael T. Rosen, Matthew S. Farrar, Christian T. |
| author_facet | Cohen, Ouri Huang, Shuning McMahon, Michael T. Rosen, Matthew S. Farrar, Christian T. |
| contents | Purpose: To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging.
Methods: We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the N$α$-amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6). The MRF acquisition schedule varied the saturation power randomly for 30 iterations (phantom: 0-6 $μ$T; in vivo: 0-4 $μ$T) with a total acquisition time of <=2 minutes. The signal trajectories were pattern-matched to a large dictionary of signal trajectories simulated using the Bloch-McConnell equations for different combinations of exchange rate, exchangeable proton volume fraction, and water T1 and T2* relaxation times.
Results: The chemical exchange rates of the N$α$-amine protons of L-Arg were significantly (p<0.0001) correlated with the rates measured with the Quantitation of Exchange using Saturation Power method. Similarly, the L-Arg concentrations determined using MRF were significantly (p<0.0001) correlated with the known concentrations. The pH dependence of the exchange rate was well fit (R2=0.9186) by a base catalyzed exchange model. The amide proton exchange rate measured in rat brain cortex (36.3+-12.9 Hz) was in good agreement with that measured previously with the Water Exchange spectroscopy method (28.6+-7.4 Hz). The semi-solid proton volume fraction was elevated in white (11.2+-1.7%) compared to gray (7.6+-1.8%) matter brain regions in agreement with previous magnetization transfer studies.
Conclusion: CEST-MRF provides a method for fast, quantitative CEST imaging. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_1710_06054 |
| institution | arXiv |
| publishDate | 2017 |
| record_format | arxiv |
| spellingShingle | Rapid and Quantitative Chemical Exchange Saturation Transfer (CEST) Imaging with Magnetic Resonance Fingerprinting (MRF) Cohen, Ouri Huang, Shuning McMahon, Michael T. Rosen, Matthew S. Farrar, Christian T. Medical Physics Purpose: To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging. Methods: We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the N$α$-amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6). The MRF acquisition schedule varied the saturation power randomly for 30 iterations (phantom: 0-6 $μ$T; in vivo: 0-4 $μ$T) with a total acquisition time of <=2 minutes. The signal trajectories were pattern-matched to a large dictionary of signal trajectories simulated using the Bloch-McConnell equations for different combinations of exchange rate, exchangeable proton volume fraction, and water T1 and T2* relaxation times. Results: The chemical exchange rates of the N$α$-amine protons of L-Arg were significantly (p<0.0001) correlated with the rates measured with the Quantitation of Exchange using Saturation Power method. Similarly, the L-Arg concentrations determined using MRF were significantly (p<0.0001) correlated with the known concentrations. The pH dependence of the exchange rate was well fit (R2=0.9186) by a base catalyzed exchange model. The amide proton exchange rate measured in rat brain cortex (36.3+-12.9 Hz) was in good agreement with that measured previously with the Water Exchange spectroscopy method (28.6+-7.4 Hz). The semi-solid proton volume fraction was elevated in white (11.2+-1.7%) compared to gray (7.6+-1.8%) matter brain regions in agreement with previous magnetization transfer studies. Conclusion: CEST-MRF provides a method for fast, quantitative CEST imaging. |
| title | Rapid and Quantitative Chemical Exchange Saturation Transfer (CEST) Imaging with Magnetic Resonance Fingerprinting (MRF) |
| topic | Medical Physics |
| url | https://arxiv.org/abs/1710.06054 |