ISMRM23 - MR Engineering I: MR Systems for Experts-to-Be

ISMRM & ISMRT Annual Meeting & Exhibition • 03-08 June 2023 • Toronto, ON, Canada

MR Engineering I: MR Systems for Experts-to-Be

Weekend Course

ORGANIZERS: Shaoying Huang, Özlem Ipek, Rolf Schulte, Xin Yu

Saturday, 03 June 2023

718B

08:00 - 11:45

Moderators: Simone Angela Winkler & Irena Zivkovic

Skill Level: Basic to Intermediate

Session Number: WE-08

CME Credit

Session Number: WE-08

Overview
This educational course will provide an overview of the engineering of an MRI system on a subsystem level. In a series of lectures from experts in MR systems engineering, attendees will learn about an MRI system and its major hardware components, including the magnet, gradients, shim coils, transmit and receive coils, as well as the operation of the electronic systems that interface with RF coils. In addition, attendees will be taught about the basics of EM simulation and characterization of the coils on the bench.

Target Audience
Scientists and clinicians who are starting to work in the field of MRI and would like to have an overview of the engineering of an MR system. More experienced researchers in particular areas of MR Engineering will also benefit from hearing about recent advances in the engineering of MR systems.

Educational Objectives
As a result of attending this course, participants should be able to:
- Describe the basic hardware components of an MRI scanner, including how they interact and function;
- Recognize practical limitations in the design of magnets, gradients, and shim systems;
- Explain the RF electronics that interface with RF coils, including separate transmit and receive coils, and describe the interactions of EM fields with the body; and
- Develop a coil characterization method using vector network analyzers on the bench.

08:00		The Magnet: Cryogen-filled to Cryogen-free View Presentation Video Thomas Foo Keywords: Physics & Engineering: Hardware, Physics & Engineering: High-Field MRI, Physics & Engineering: Physics Outline of a presentation describing the differences in magnet design for a conventional cryogen-filled magnet and that of a cryogen-free magnet.
08:25		Gradient Coils View Presentation Video Sebastian Littin Keywords: Physics & Engineering: Hardware The spatial encoding system, usually termed gradients, is crucial for magnetic resonance imaging (MRI). Gradient coils for MRI are usually designed using target field methods. The stream function method allows for approximating surface current densities by discrete wires. One of the main limiting factors of gradient coils in MRI is given by physiological constraints, namely peripheral nerve stimulation (PNS). As PNS properties of smaller coils are beneficial, head insert coils are experiencing a revival. Further localized, application-specific coils might be used to overcome today’s limitations. Different approaches have been used to implement complex wire geometries into realizable coil designs.
08:50		B0 Shimming: Coils and Methods View Presentation Video Jason Stockmann Keywords: Physics & Engineering: Hardware, Physics & Engineering: Physics We describe how tissue susceptibility interfaces disturb the main B₀ magnetic field inside the scanner bore, causing a wide variety of artifacts in MR acquisitions. We review field mapping approaches for measuring these ΔB₀ field deviations, along with factors influencing field map accuracy and precision. Hardware for nulling the unwanted ΔB₀ fields is then covered, including both passive shim inserts and active shim coils. We show how to simulate B₀ shim performance for specific shim coils as well as for the "ultimate shim" using optimized coils. Last, we highlight open-source resources including shim optimization software and published coil wire patterns.
09:15		RF Frontend View Presentation Video Boris Keil
09:40		Break & Meet the Teachers
10:05		Transmit Coils View Presentation Video Elmar Laistler Keywords: Physics & Engineering: Hardware This lecture covers different aspects of transmit coils, ranging from coil types, associated circuitry and components to safety aspects.
10:30		Receive Coils & Combined Shim-RF Arrays View Presentation Video Hui Han Keywords: Physics & Engineering: Hardware, Physics & Engineering: High-Field MRI, Body: Body In this lecture, we'll explore the use of receive coils, including newly developed combined shim-RF arrays (1-7), for high-field imaging. Traditional volume RF coils are replaced by phased array coils, which use local RF surface coils on the human body for improved sensitivity and faster imaging. But B0 field inhomogeneity remains a major challenge for many high-field MRI applications. We'll discuss the concept of combined shim-RF arrays, which integrate a shim array into a receive coil to address this issue and improve image quality.
10:55		Characterization of Coils on the Bench View Presentation Video Karthik Lakshmanan Keywords: Physics & Engineering: Hardware During RF coil design and construction process characterization (bench testing) is a necessary step to ensure coil functionality and optimal performance. This lecture will explore and elaborate on critical functional and performance metrics of RF Coils.
11:20		Break & Meet the Teachers