ISMRM20 Sunrise: Simulation of Diffusion

Sunrise Session

Simulation of Diffusion

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Session Topic: Educational Q&A: fMRI/Diffusion/Perfusion Sunrise

Session Sub-Topic: Simulation of Diffusion

Sunrise Session

ORGANIZERS: Dmitry Novikov, Carl-Fredrik Westin

Tuesday Parallel 1 Live Q&A

Tuesday, 11 August 2020, 13:45 - 14:30 UTC

Moderators:

Skill Level: Basic to Advanced

Session Number: S-W-04

Overview
Monte Carlo simulations of diffusion-weighted signal have come to the forefront of the tissue microstructure imaging with MRI. While the primary interest in this tool has emerged within the diffusion community, this technique will be also of interest to researchers interested in validating models of transverse relaxation and magnetization transfer. The two lectures will describe the basics of Monte Carlo dynamics, efficient strategies to model locally varying diffusivity and permeability, and applications of this methodology for the model validation of diffusion in realistic tissue geometries.

Target Audience
Researchers interested in setting up their own numerical simulations or using Monte Carlo simulations of diffusion for model validation.

Educational Objectives
As a result of attending this course, participants should be able to:
- Explain the basics of the Monte Carlo method;
- Recognize typical errors and pitfalls involved;
- Simulate the microscopic Bloch-Torrey dynamics in tissues with spatially varying diffusion coefficient and permeable and impermeable membranes; and
- Name existing software implementations and examples of model validation using Monte Carlo simulations.

		How to Set Up Monte Carlo Simulations of Diffusion Hong-Hsi Lee Watch the Video To validate biophysical models of diffusion MRI, Monte Carlo (MC) simulations are flexible and straightforward to set up for all kinds of tissue properties and micro-geometries. The ensemble averages of numerous particles' random walks provide estimates of diffusion propagators and statistically meaningful diffusion metrics. Here, we introduce the basic principles of MC simulations and the common mistakes especially for simulations of permeable membranes. Finally, we propose a short to-do list for the near future of this field.
		Using Simulations to Validate Models Marco Palombo Watch the Video This lecture targets scientists and clinicians interested in learning what are the most recent developments in numerical simulations, with a particular focus on their use for the validation of commonly used diffusion MRI (dMRI) models of tissue microstructure. We will provide an overview of the aspects of dMRI techniques that can be validated with numerical phantoms, and of the range of numerical phantoms that are currently available. Examples of how to use numerical phantoms for validating dMRI techniques will be provided and future perspectives on the next-generation numerical phantoms will be discussed.