Dipolar Order Parameters in Large Systems With Fast Spinning

Order parameters are a useful tool for quantifying amplitudes of molecular motions. Here we measure dipolar order parameters by recoupling heteronuclear dipole-dipole couplings under fast spinning. We apply symmetry based recoupling methods to samples spinning under magic angle at 60 kHz by employing a variable flip angle compound inversion pulse. We validate the methods by measuring site-specific 15N-1H order parameters of a microcrystalline protein over a small temperature range and the same protein in a large, precipitated complex with antibody. The measurements of the order parameters in the complex are consistent with the observed protein undergoing overall motion within the assembly.

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Technical Note: The effect of 2D excitation profile on T1 measurement accuracy using the variable flip angle method with an average flip angle assumption

Medical Physics ◽

10.1002/mp.12513 ◽

2017 ◽

Vol 44 (11) ◽

pp. 5930-5937 ◽

Cited By ~ 3

Author(s):

Bryant T. Svedin ◽

Dennis L. Parker

Keyword(s):

Measurement Accuracy ◽

Technical Note ◽

Flip Angle ◽

Variable Flip Angle ◽

Excitation Profile ◽

Angle Method

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Accuracy of equilibrium magnetization mapping in sliced two-dimensional spoiled gradient-recalled echo pulse sequence with variable flip angle

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.24023 ◽

2013 ◽

Vol 38 (5) ◽

pp. 1245-1250

Author(s):

Hideto Kuribayashi ◽

Masaki Sekino ◽

Takuya Minowa ◽

Yoshie Maitani ◽

Hiroyuki Ohsaki ◽

...

Keyword(s):

Pulse Sequence ◽

Flip Angle ◽

Two Dimensional ◽

Variable Flip Angle ◽

Equilibrium Magnetization ◽

Echo Pulse

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Snapshot whole-brain T1relaxometry using steady-state prepared spiral multislice variable flip angle imaging

Magnetic Resonance in Medicine ◽

10.1002/mrm.26746 ◽

2017 ◽

Vol 79 (2) ◽

pp. 856-866 ◽

Cited By ~ 2

Author(s):

Rahel Heule ◽

Josef Pfeuffer ◽

Oliver Bieri

Keyword(s):

Steady State ◽

Flip Angle ◽

Variable Flip Angle ◽

Whole Brain

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A New Similarity Metric for Groupwise Registration of Variable Flip Angle Sequences for Improved T 10 Estimation in DCE-MRI

Biomedical Image Registration - Lecture Notes in Computer Science ◽

10.1007/978-3-319-08554-8_16 ◽

2014 ◽

pp. 154-163 ◽

Cited By ~ 3

Author(s):

Andre Hallack ◽

Michael A. Chappell ◽

Mark J. Gooding ◽

Julia A. Schnabel

Keyword(s):

Flip Angle ◽

Variable Flip Angle ◽

Similarity Metric ◽

Dce Mri ◽

Groupwise Registration

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A practical guideline for T1 reconstruction from various flip angles in MRI

Journal of Algorithms & Computational Technology ◽

10.1177/1748301816656288 ◽

2016 ◽

Vol 10 (4) ◽

pp. 213-223 ◽

Cited By ~ 1

Author(s):

Constantin Sandmann ◽

Erlend Hodneland ◽

Jan Modersitzki

Keyword(s):

Sensitivity Analysis ◽

Linear Method ◽

Real Data ◽

Flip Angle ◽

Robust Method ◽

Variable Flip Angle ◽

Nonlinear Approach ◽

Reconstruction Methods ◽

The Family ◽

Linear Reconstruction

A fast and robust method for T1 estimation in MRI is the so-called variable flip angle technique. We introduce a novel family of T1 reconstruction methods from data acquired with various flip angles and propose a family member which combines the robustness of a nonlinear- with the computational advantages of a linear reconstruction. The constructed family contains the most common approaches for T1 estimation, namely a linear and a nonlinear approach. A general sensitivity analysis for arbitrary members of the family is established. Advantages of the optimized reconstruction are demonstrated on phantom- as well as real data, showing improvements of up to 24% as compared with the linear method. As a further means to stabilize T1 estimation, spatial stabilization methods are compared. We demonstrate on phantom and on real data that improved results can be obtained if not only T1 but also a second unknown M0 in the reconstruction is stabilized.

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