Analytical Dual Flip Angle R1 Calculation Outside the Small‐Angle Regime
Luke J. Edwards, Kerrin J. Pine, Ilona Lipp, Evgeniya Kirilina, Gunther Helms, Nikolaus Weiskopf, Catherine Crockford, Luke J. Edwards, Angela D. Friederici, Tobias Gräßle, Philipp Gunz, Carsten Jäger, Evgeniya Kirilina, Ilona Lipp, Kerrin Pine, Matyas Liptovszky
TL;DR
This paper introduces a new method for calculating R1 and proton density from MRI data that works well even with large flip angles.
Contribution
A novel analytical estimator for R1 and apparent proton density that avoids the small flip angle approximation.
Findings
The novel method avoids flip angle-dependent bias seen in traditional small-angle methods.
The new method preserves precision with negligible differences in coefficients of variance.
The method is more accurate and broadly applicable for a wider range of MRI data.
Abstract
To evaluate a new analytical estimator for R1 and apparent proton density (A) from short‐TR dual flip angle data which does not rely on the small flip angle approximation and can thus be applied to a broader range of data, especially where relatively large flip angles are needed to achieve sufficient T1‐weighting for R1 estimation. A rational approximation of the Ernst equation was derived for small R1·TR and rearranged to give analytical estimators of R1 and A from dual flip angle data. Unlike previously used analytical estimators, this method relies neither on the flip angles being small nor the two TRs being equal or integer multiples of each other. R1 and A estimated using the novel method were compared to estimates using the conventional small‐angle approximation approach in simulations and data measured at 7T from six in vivo human participants and a postmortem chimpanzee brain.…
Genes, proteins, chemicals, diseases, species, mutations and cell lines named across the full text — each resolved to its canonical identifier and authoritative record.
Click any figure to enlarge with its caption.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
Figure 24
Figure 25
Figure 26
Figure 27
Figure 28
Figure 29Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsScientific Measurement and Uncertainty Evaluation · Advanced Electrical Measurement Techniques · Fluid Dynamics and Turbulent Flows