Related Experiment Video
Updated: Jul 7, 2026
09:25
NMR 15N Relaxation Experiments for the Investigation of Picosecond to Nanoseconds Structural Dynamics of Proteins
Published on: November 1, 2024
Parameter relations for the Shinnar-Le Roux selective excitation pulse design algorithm [NMR imaging]
J Pauly1, P Le Roux, D Nishimura
1Inf. Syst. Lab., Stanford Univ., CA.
IEEE Transactions on Medical Imaging
|January 1, 1991
Summary
The Shinnar-Le Roux (SLR) algorithm enables precise analytical specification of radiofrequency pulse performance. This allows for designing pulses with desired slice profiles and optimizing performance trade-offs.
Area of Science:
- Magnetic Resonance Imaging
- Pulse Sequence Design
Background:
- The Shinnar-Le Roux (SLR) algorithm is a key method for designing radiofrequency (RF) pulses in Magnetic Resonance Imaging (MRI).
- Accurate control over pulse performance is crucial for achieving desired imaging outcomes, such as specific slice profiles.
Purpose of the Study:
- To provide an overview of the Shinnar-Le Roux (SLR) algorithm.
- To demonstrate the analytical specification of SLR pulse performance.
- To guide the design of RF pulses with specified slice profiles and controllable performance trade-offs.
Main Methods:
- Analytical characterization of Shinnar-Le Roux (SLR) pulse performance.
- Exploration of design strategies for achieving specific slice profiles.
- Evaluation of trade-offs between different pulse parameters.
Main Results:
- The performance of SLR pulses can be accurately specified using analytical methods.
- Design strategies allow for the creation of pulses with precisely defined slice profiles.
- Trade-offs between pulse parameters, such as phase characteristics and slice profile quality, are elucidated.
Conclusions:
- The Shinnar-Le Roux (SLR) algorithm offers powerful analytical tools for RF pulse design in MRI.
- Understanding these analytical specifications enables optimization of pulse performance for specific applications.
- Different pulse types (linear-phase, minimum-phase, maximum-phase) offer distinct advantages and limitations in terms of slice profile and refocusing capabilities.
More Related Videos
07:24Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins
Published on: September 23, 2021
08:01Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo
Published on: September 26, 2016
Related Concept Videos
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:14NMR Spectrometers: Resolution and Error Correction
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
01:12Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
01:15Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
01:10Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the others.
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...