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Robust estimation of quantitative perfusion from multi‐phase pseudo‐continuous arterial spin labeling

Msayib, Y.; Craig, M.; Simard, M. A.; Larkin, J. R.; Shin, D. D.; Liu, T. T.; Sibson, N. R.; Okell, T. W.; Chappell, M. A.

Robust estimation of quantitative perfusion from multi‐phase pseudo‐continuous arterial spin labeling Thumbnail


Authors

Y. Msayib

M. Craig

M. A. Simard

J. R. Larkin

D. D. Shin

T. T. Liu

N. R. Sibson

T. W. Okell



Abstract

Purpose
Multi‐phase PCASL has been proposed as a means to achieve accurate perfusion quantification that is robust to imperfect shim in the labeling plane. However, there exists a bias in the estimation process that is a function of noise in the data. In this work, this bias is characterized and then addressed in animal and human data.

Methods
The proposed algorithm to overcome bias uses the initial biased voxel‐wise estimate of phase tracking error to cluster regions with different off‐resonance phase shifts, from which a high‐SNR estimate of regional phase offset is derived. Simulations were used to predict the bias expected at typical SNR. Multi‐phase PCASL in 3 rat strains (n = 21) at 9.4 T was considered, along with 20 human subjects previously imaged using ASL at 3 T. The algorithm was extended to include estimation of arterial blood flow velocity.

Results
Based on simulations, a perfusion estimation bias of 6‐8% was expected using 8‐phase data at typical SNR. This bias was eliminated when a high‐precision estimate of phase error was available. In the preclinical data, the bias‐corrected measure of perfusion (107 ± 14 mL/100g/min) was lower than the standard analysis (116 ± 14 mL/100g/min), corresponding to a mean observed bias across strains of 8.0%. In the human data, bias correction resulted in a 15% decrease in the estimate of perfusion.

Conclusions
Using a retrospective algorithmic approach, it was possible to exploit common information found in multiple voxels within a whole region of the brain, offering superior SNR and thus overcoming the bias in perfusion quantification from multi‐phase PCASL.

Citation

Msayib, Y., Craig, M., Simard, M. A., Larkin, J. R., Shin, D. D., Liu, T. T., …Chappell, M. A. (2020). Robust estimation of quantitative perfusion from multi‐phase pseudo‐continuous arterial spin labeling. Magnetic Resonance in Medicine, 83(3), 815-829. https://doi.org/10.1002/mrm.27965

Journal Article Type Article
Acceptance Date Aug 2, 2019
Online Publication Date Aug 20, 2019
Publication Date 2020-03
Deposit Date Sep 28, 2020
Publicly Available Date Oct 15, 2020
Journal Magnetic Resonance in Medicine
Print ISSN 0740-3194
Electronic ISSN 1522-2594
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 83
Issue 3
Pages 815-829
DOI https://doi.org/10.1002/mrm.27965
Keywords Radiology Nuclear Medicine and imaging
Public URL https://nottingham-repository.worktribe.com/output/4930898
Publisher URL https://onlinelibrary.wiley.com/doi/full/10.1002/mrm.27965

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