Magnetic Resonance Image Characteristics

 

Outline and Learning Guide


INTRODUCTION AND OVERVIEW

THE MR IMAGE
Tissue Characteristics and Image Types
Proton Density (PD) Image
Magnetic Relaxation Times T1 and T2 Images

Fluid Movement and Image Type
  Vascular Flow
Perfusion and Diffusion

Spectroscopic and Chemical Shift

WHAT DO YOU SEE IN AN MR IMAGE?
Radio Frequency Signal Intensity
Tissue Magnetization
Protons (Magnetic Nuclei)
Hydrogen
Tissue Characteristics
 PD (Proton Density)
T1
T2

SPATIAL CHARACTERISTICS
Slices
Voxels
 Image Pixels

CONTROL OF IMAGE CHARACTERISTICS
Contrast Sensitivity
Detail
Noise
Artifacts
Spatial

 IMAGE ACQUISITION TIME

 PROTOCOL OPTIMIZATION

 MIND MAP and SUMMARY

 

 

Learning Objectives

  • Identify the type of radiation that is emitted from the patient's body and displayed in a magnetic resonance image.
     
  • Identify the temporary physical condition in the tissue of the patient's body that is the source of the emitted radiation.
     
  • Name the three basic tissue magnetic characteristics that are the sources of contrast in magnetic resonance images.
     
  • Name three types of fluid movement that can be imaged with MRI.
     
  • Explain the significance and roll of the element hydrogen in MRI.
     
  • Give a more descriptive name for the two tissue characteristics commonly known as T1 and T2.
     
  • Explain what is meant by a weighted image, as in a T1 weighted image.
     
  • Identify the characteristic of signals emitted by tissue that is affected by the type of molecules and is the basis of MR chemical spectroscopy.
     
  • Describe the characteristic of protons that make them different from many other atomic nuclei and make them useful in the MRI process.
     
  • Describe how a section of a patient's body is typically divided and viewed as images in MRI.
     
  • Sketch and illustrate the concept of a voxel.
     
  • Sketch and illustrate the concept of a pixel.
     
  • Describe the concept of contrast sensitivity and how it relates to MRI.
     
  • Describe the concept of image detail and why it is an important characteristic in medical imaging.
  • Identify the factor associated with all imaging procedures that limits visibility of detail in an image.
     
  • Describe the general appearance of noise in an image and why it is often an undesirable characteristic.
     
  • While looking at a magnetic resonance image, identify the noise.
     
  • Describe the general appearance of artifacts in images.
     
  • When viewing magnetic resonance images, recognize artifacts if they are present.
     
  • An imaging procedure is controlled by a protocol of selected imaging parameters. Explain the general concept of an optimized protocol.

 

 

Text Reference

Chapter 1

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

 

 

Mind Map