Klein Hans-Martin. Clinical Low Field Strength Magnetic Resonance Imaging: A Practical Guide to Accessible MRI

Springer International Publishing, 2016. — 156 p. — ISBN: 978-3-319-16515-8,978-3-319-16516-5.This book covers all aspects of low field MRI, describing its advantages, problems and prerequisites. Individual chapters are devoted to site planning, safety considerations, coils, imaging technique, image quality optimization, the imaging of different anatomic regions and likely future developments. The factors that must be borne in mind when selecting a low field system are clearly identified and detailed attention is paid to the applications for which such a system is adequate.The focus on high field systems has led to a situation where only a few systems with field strengths lower than 0.5 T survive. Some of these systems possess high field features such as multichannel coils and strong gradients; furthermore, sequence technology and image processing techniques taken from higher field strength systems have resulted in impressive imaging capabilities. While 1.5-T systems will probably continue to remain the standard, low field systems offer advantages such as the feasibility of dynamic joint examinations, improvement of T1 contrast, reduction of “missile effects” and decreased radiofrequency exposure. Low field strength MRI consequently has the potential to contribute to optimal patient management and given comparable image quality, its application may become an issue of patient safety. This book will be an invaluable asset to all who are involved in planning and/or running a low field strength MRI facility.HistoryMRI System
Magnet
Permanent Magnets
Electromagnets
Superconducting Magnets
Dedicated Systems
Homogeneity
Vertical or Horizontal Magnetic Field?
Gradients
Gradient Chain
Rise Time and Slew Rate
Eddy Currents
RF Chain
Transmitter
Coils
Back End
QualitySite Planning
MRI System Components
Room Size and Conditions
Transport and Installation
Static Requirements
Power Supply and Cooling
Sound and Vibration
Static Magnetic Field
Distortion of the Magnetic Field
Distortion of Equipment by the MRI Magnetic Fringe Field
RF Shielding
Room Light, Reporting Stations
Warning SignsSafety Considerations
Static Magnetic Fields
Gradient Magnetic Fields
Radiofrequency Fields
Acoustic Noise
Claustrophobia
Pacemaker
Other Devices
Cerebrospinal Fluid Valves
Cochlear Implants
Bullets, Pellets, ShrapnelLow-Field-Specific Physical Aspects
Larmor Frequency and Chemical Shift
Homogeneity
T1 Relaxation
Contrast-Enhanced Imaging
Bandwidth
RF Deposition
Susceptibility
Sensitivity to Motion
Dielectric Effects
Signal-to-Noise RatioLow-Field Imaging Technique
Positioning
Sequences
Spin Echo
Multi-Spin Echo
Gradient Echo
Rapid Gradient Echo Imaging
3D Imaging
Fat Saturation
Diffusion Imaging
Angiographic Techniques
Spatial Resolution
Matrix
Interpolation
Contrast
Contrast to Noise
Number of Excitations
Postprocessing
Temporal Resolution
Partial Scan
Parallel Imaging
Contrast Agents
Positive Contrast Agents
Negative Contrast Agents
Gadolinium
Ventilation Imaging
Enteral Contrast Agents
Artifacts
Distortion of the Magnetic Field
RF and Gradients
Motion
Signal ProcessingClinical Application
Cranial Imaging
Neck Imaging
Spine
Musculoskeletal Imaging
Trauma
Inflammatory Disease
Cartilage
Joint Imaging
Thoracic Imaging
Abdomen
Vascular Imaging
Diffusion
Functional Imaging
Whole Body
Cardiac Imaging
Functional Imaging
Perfusion Imaging
Late Enhancement
Implants
Interventional MRIEconomy and Ecology
Investment
Location
System Components
Installation
Financing
Operational Costs
Room Costs
Energy
Maintenance Costs
Employees
Variable Costs
Cost Calculation
Effects on Ecology and Environment
Helium
Magnet
Electric Power Consumption
Heating PowerFuture Developments
Technical Improvements
Magnet Design
Gradients
Signal Production and Processing
Coils
Hyperpolarization
Zero-Energy MR Site10 Conclusion