One of the most important developments in diagnostic imaging over the last decade has been magnetic resonance imaging (MRI). Its ability to differentiate between tissues and give patholog- ical information about diseases has led to earlier treatment, thus increasing the likelihood of recovery. The images produced using this technique give superb anatomical detail in any plane and are obtained without the use of ionising radiation. The increased use of MRI has presented radiographers with a number of challenges, and because we are no longer dealing with ionising radiation understanding the subject can some- times be confusing. We hope that this text will help radiographers and student radiographers to further their knowledge and unravel the mysteries of MRI. Philip T. English Christine Moore Contents 1 Basic Principles . . . . . . . . . 1 History ..... . 1 Atomic Theory . . 1 Magnetic Theory . 2 Resonance 4 Relaxation. . . . . 5 2 Instrumentation........ 9 The Magnet .. 9 Shim Coils ........... . 12 Gradient Coils ......... . 13 RF Transmitter/Receiver Coils. 14 The Computer . . . . . . . . . 18 3 Pulse Sequences. . . . . . . . . 19 Saturation Recovery (Partial Saturation) 19 Spin Echo (SE) . . . . . . . . . . . . . 20 Multiple Spin Echo. . . . . . . . . . . 22 Fast Spin Echo (FSE) or Turbo Spin Echo (TSE). 23 Inversion Recovery (IR) . . . . . . . . . . . . . 26 Gradient Echo .................. . 28 Magnetisation Transfer Contrast Imaging (MTC) 34 4 Image Production. . . . . . . .
1 Basic Principles.- History.- Atomic Theory.- Magnetic Theory.- Resonance.- Relaxation.- 2 Instrumentation.- The Magnet.- Shim Coils.- Gradient Coils.- RF Transmitter/Receiver Coils.- The Computer.- 3 Pulse Sequences.- Saturation Recovery (Partial Saturation).- Spin Echo (SE).- Multiple Spin Echo.- Fast Spin Echo (FSE) or Turbo Spin Echo (TSE).- Inversion Recovery (IR).- Gradient Echo.- Magnetisation Transfer Contrast Imaging (MTC).- 4 Image Production.- Spatial Location of the MR Image.- Slice Selection Excitation.- Slice Position.- Slice Profile.- 5 Image Quality.- Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR).- Other Factors Contributing to Image Quality.- Quality Assurance in MRI.- 6 Image Artifacts.- Magnetic Field Artifacts.- Hardware-Related Artifacts.- Motion-Related Artifacts.- Pulse Sequence/Data Acquisition Artifacts.- Other Artifacts.- 7 Flow.- Haemodynamics.- Appearance of Flow on MR Images.- Magnetic Resonance Angiography (MRA).- Measurement of Flow.- 8 MR Contrast Agents.- Basic Principles of a Contrast Agent's Actions.- Paramagnetic Agents.- Ferromagnetic Agents.- 9 Safety and Patient Management.- Safety.- Patient Management.- 10 Site Planning.- Location.- The Magnet.- The Fringe Field.- RF Shielding.- Equipment.- Patient and Staff Requirements.- Anaesthesia in MRI.- 11 Applications and Pathology.- The Brain.- The Spine.- Brachial Plexus.- Head and Neck.- Musculoskeletal System.- Long Bones.- Abdomen.- The Pelvis.- Breast Imaging.- Chest and Thorax.- Cardiovascular System.- Paediatric Imaging.- Suggested Reading.- Glossary of MR Terms.
