September 17, 2025

Low-frequency asymptotic behaviour of the apparent diffusion coefficient when measured with approximate cosinusoidal gradient waveforms

Key Points

The low-frequency behavior of the apparent diffusion coefficient (ADC) varies with different MPG waveforms, impacting analysis.
Initial predictions show significant differences in ADC behavior when measured with CPHS and DS waveforms compared to an ideal cos waveform.
A theoretical study was conducted to derive ADC behavior for three different MPG waveforms, enhancing understanding of gradient waveform limitations.
These findings highlight the importance of considering hardware limitations in interpreting microstructural data from OGSE-DWI.

Abstract

Motivation: Existing theory for OGSE-DWI has been developed under the assumption of an ideal cosinusoidal gradient waveform, but it is impossible to implement such a waveform in practice. Goal(s): Investigate how the low-frequency asymptotic behaviour of the ADC is affected when OGSE-DWI measurements are performed with an approximate cosinusoidal waveform. Approach: A theoretical study was performed to derive the asymptotic behaviour of the ADC from first principles for three MPG waveforms. Results: The predicted low-frequency behaviour of the ADC for the CPHS and DS waveforms can clearly differ from that for the ideal cos waveform. Impact: The microstructure of a complex medium can be characterised by measuring the low-frequency limit of the ADC with OGSE-DWI. However, it is important to understand how the limitations of the gradient hardware affect interpretation of the data.

Mark Helpful

Bookmark

Relay