Magnetic Resonance Image Spatial Characteristics

Outline

Mind Map

Learning Objectives

Teaching Visuals

Online Module
(Requires Enrollment)

Text Reference

 

Outline and Learning Guide


INTRODUCTION AND OVERVIEW

SIGNAL ACQUISITION

IMAGE RECONSTRUCTION

IMAGE CHARACTERISTICS

GRADIENTS

SLICE SELECTION

Selective Excitation

Multi-Slice Imaging

Volume Acquisition

FREQUENCY ENCODING

Resonant Frequency

PHASE ENCODING

THE GRADIENT CYCLE

IMAGE RECONSTRUCTION

MIND MAP and SUMMARY

 

 

Learning Objectives

 
  • Name and briefly describe what happens in the two principle phases in the MR imaging process.

     
  • Identify and describe the major spatial characteristics of an MR image.

     
  • Describe and illustrate the concept of k space and explain it's role in the MR imaging process.

     
  • Name and compare the two general methods used to produce slices in MR imaging.

     

  • Describe a magnetic field gradient and explain how it is produced.

     
  • Explain and illustrate how the process of selective excitation produces slices.

     
  • Explain and illustrate how the process of multiple slice imaging can produce many slice images without an increase in acquisition time.

     
  • Identify the principle imaging protocol factor that limits the number of slices that can be imaged in one multiple slice acquisition. 

     
  • Briefly describe the general advantage and disadvantage of using the 3-D volume acquisition method.

     
  • Explain and illustrate how a gradient is used to produce frequency encoding.

     
  • Describe and illustrate the concept of a phase difference between signals from voxels.

     
  • Describe how a gradient is used to produce phase encoding.

     
  • Describe the relationship between phase encoding and the rows of k space.

     
  • Identify the characteristic of the phase encoding gradient that is changed from one step to another during the phase encoding process.

     
  • Identify and briefly describe the
    RF activity that occurs while the slice selection gradient is applied.

     
  • Identify and briefly describe the RF activity that occurs while the phase encoding gradient is applied.

     
  • Describe the order in which the three gradient actions occur during a typical imaging cycle.

     
  • Identify the mathematical process that is used for image reconstruction in MRI.

     
  • Describe in very general terms what happens in the MR image reconstruction process.

     
  • Compare the acquisition and reconstruction phases with respect to number of protocol factors that must be considered and adjusted.
     
 

 

Text Reference

Chapter 9

Magnetic Resonance Imaging: Principles, Methods, and Techniques
Medical Physics Publishing,  http://www.medicalphysics.org

 

 

Mind Map