# Practical Magnetic Resonance Imaging I

#### Biomedical Imaging Graduate Program

Riccardo Lattanzi, PhD

Ryan Brown, PhD

Lectures and laboratory sessions #1-5 will be held at the NYU Center for Biomedical Imaging (CBI), at 660 1st avenue, in the 4th floor small conference room. Laboratory sessions #6-10 will be held in the RF laboratory at CBI.

This course is a practical introduction to the basic components of signal excitation and detection in magnetic resonance imaging (MRI). The course is divided in three modules. The first part focuses on the fundamental mathematical tools needed to describe an MRI experiment and how they can be implemented in the Matlab software environment. The second part introduces students to the basics of pulse sequence design, providing examples and direct programming experience. In the third part, students will learn the principles of radiofrequency (RF) coil design and they will build a receive coil. The class involves significant laboratory work. Prerequisites are basic knowledge of C++, G16.4404 or permission of the course director for students not enrolled in the Sackler training program in biomedical imaging.

- Provide an introduction to the Matlab commands used in MRI research.
- Teach the basic concepts of pulse programming and RF coil design.
- Take advantage of facilities and staff of the pulse programming and RF engineering cores at the Center for Biomedical Imaging (CBI) to give students a unique opportunity of translating theory into practice.

## Syllabus

- Introduction to the course
- Commonly used functions (unit step, signup, delta, sinc, etc.)
- Convolution
- LTI systems
- Sampling functions
- Periodic singnals
- Matlab demonstration

- The Fourier Transform: definition and properties
- Discrete Fourier Transform and Fast Fourier Transform (FFT) algorithm
- The Radon Transform
- Matlab demonstration

- Matlab workspace
- M-files: script files and function files
- Matrix operations, array operations
- For, while, if
- Graphics
- Image processing toolbox

- Spin-lattice and spin-spin interactions
- The Bloch equation
- Small-tip-angle approximation
- Free induction decay

- Rectangular pulses
- SINC pulses
- SLR pulses
- Variable-rate pulses
- Excitation pulses
- Inversion pulses

- Requirements and installation
- SyngoMR overview
- IDEA overview
- C++ review

- Simple gradient lobes
- Bridged gradient lobes
- Frequency-encoding gradients
- Phase-encoding gradients
- Slice selection gradients

- Bandwidth and sampling
- K-space sampling trajectories
- Two- and three-dimensional acquisition

- Sequence building blocks
- The real time event concepts
- Hardware instructions
- Data acquisition
- Phase encoding

- Gradient echo
- Inversion recovery
- Spin echo

- Echo planar imaging
- Phase contrast
- Diffusion imaging
- Dixon's method

- Sequence debugging
- UI programming
- Sequence testing
- Image Calculation Environment (ICE)

- RF shimming and parallel MR transmission
- B
_{1}-mapping - Accelerated and SAR minimization
- Two- and Three-dimensional selective excitation

- FLASH sequence
- Spin Echo sequence

- Kirchoff's circuit laws
- Resistors, capacitors, inductors
- RLC resonant circuits
- Transmission lines
- Tuning and matching

- Loop coil
- Solenoid coil
- Helmholtz coil
- Birdcage coil
- TEM coil

- Network analyzer
- Soldering
- Blocking network

- Transmit detuning
- Preamplifiers
- Array coupling (inductive, electric, resistive)
- Surface arrays
- Design considerations for many-element arrays

- Array decoupling
- Power RF amplifiers
- Transmit-receive arrays
- Multi-channel TEM coils
- Multi-tuned coils

- Coil decoupling
- Balun/cable trap
- Construction of a simple loop RF coil: finish

- FireVoxel segmentation tools
- Signal-to-noise ratio
- Quality factor
- Coil homogeneity
- Filling factor
- Ultimate intrinsic SNR
- Coil performance maps

- Electromagnetic field theory
- Quasi-static regime and Biot-Savart's law
- The Finite Difference Time Domain (FDTD) method
- The Dyadic Green's function method
- Relating field calculation results to MRI

- Acquire an image of phantom using the constructed RF coils and the pulse sequence developed in part 2 of the course

J. Thomas Vaughan and John R. Griffiths, RF coils for MRI, Wiley-Liss, 2012. ISBN 978-0-470-77076-4

M. A. Bernstein, K. F. King and X. J. Zhou, Handbook of MRI Pulse Sequences, Academic Press, 2004. ISBN 0120928612

The software Matlab (The MathWorks, Inc.) will be provided to students under the available NYU institutional license. The IDEA pulse sequence programming environment will be provided to students under an agreement between the NYU Langone Medical Center and Siemens Healthcare.

The course meets twice per week and it is organized as fifteen 120-minute lectures, ten 240-minute labs, a midterm and a final exam. Students will be evaluated based upon course participation (10%), midterm exam (25%), final exam (25%), and laboratory projects (40%).

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#### Philanthropic Support

We gratefully acknowledge generous support for radiology research at NYU Langone Medical Center from:

• The Big George Foundation

• Raymond and Beverly Sackler

• Bernard and Irene Schwartz

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