Publication

Evaluation of the effects of motion on dynamic pTx pulse optimization at 7T

Jean-Philippe Thiran
2025

Abstract

Motivation: The performance of dynamic pTx pulses might be affected by patient motion, especially in the case of long scanning sessions. Goal(s): To examine the actual impact of motion on the flip angle map of a pTx pulse optimized with a fast online customization (FOCUS) strategy. Approach: B0 and multi-channel B1+ maps were acquired at multiple head positions, and the application of the pulse optimized on the first position was simulated on the subsequent positions. Results: For various ranges of motion measured in this study, FOCUS pTx pulses are demonstrated to be robust to motion occurring after the acquisition of the field maps. Impact: Fast online customized pTx pulses suffer from motion during long scanning sessions, mainly due to changes in B1+ field distribution. However, for motion amplitudes comparable to what was measured, the negative impact on low flip angle non-selective pulses is negligible.

Official source

https://infoscience.epfl.ch/entities/publication/7e9eadb1-cdcf-4260-a78f-b707c28f9170

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Jean-Philippe Thiran
2025

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/7e9eadb1-cdcf-4260-a78f-b707c28f9170

About this result

Related concepts (25)

Motion capture

Motion capture (sometimes referred as mo-cap or mocap, for short) is the process of recording the movement of objects or people. It is used in military, entertainment, sports, medical applications, and for validation of computer vision and robots. In filmmaking and video game development, it refers to recording actions of human actors and using that information to animate digital character models in 2D or 3D computer animation. When it includes face and fingers or captures subtle expressions, it is often referred to as performance capture.

Motion

In physics, motion is the phenomenon by which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and frame of reference to an observer, measuring the change in position of the body relative to that frame with a change in time. The branch of physics describing the motion of objects without reference to their cause is called kinematics, while the branch studying forces and their effect on motion is called dynamics.

Pareto distribution

The Pareto distribution, named after the Italian civil engineer, economist, and sociologist Vilfredo Pareto, is a power-law probability distribution that is used in description of social, quality control, scientific, geophysical, actuarial, and many other types of observable phenomena; the principle originally applied to describing the distribution of wealth in a society, fitting the trend that a large portion of wealth is held by a small fraction of the population.