RF Coils for MRI

Radiofrequency (RF) coils are the antennae of MRI instruments, used to both stimulate and receive the signals. Modern clinical and preclinical MRI systems use coil circuits ranging from single, passive LC loops to electronically controlled, multiple element phase arrays and cryogenically cooled probe–heads.

This handbook will serve as an expository guide for engineers, scientists, medical physicists, radiographers, technologists, hands–on radiologists and other physicians, and for anyone with interest in building, purchasing or selecting and using coils to achieve the best clinical or experimental results. It combines the lifetime understanding and expertise of many of the senior designers in the field into a single, practical training manual on how to design, build, and use their most effective designs. Tricks of the trade and other proprietary information, part numbers and sources of component materials, equipment, engineering services and consulting are all included, enabling anyone with electronics bench experience to build, test and interface a coil.

The handbook also teaches the MR system user how to safely and successfully implement the coil for its intended application. The chapters include information required by the scientist or physician to predict respective experiment or clinical performance of a coil for a variety of common applications.

RF Coils for MRI will become an important resource for engineers, technicians, scientists, and physicians wanting to safely and successfully build (or buy) and use MR coils in the laboratory of clinic. Similarly, this handbook provides teaching material for student, fellows and residents wanting to better understand the theory an operation of RF coils.

Contributors ix

Series Preface xiii

Volume Preface xv

Part A: Surface Coils 1

1 An Historical Introduction to Surface Coils: The Early Days 3
Joseph J. H. Ackerman

2 Radiofrequency Coils for NMR: A Peripatetic History of Their Twists and Turns 9
Eiichi Fukushima

3 Quadrature Surface Coils 17
Christopher M. Collin and, Andrew G. Webb

4 Double–Tuned Surface Coils 27
Barbara L. Beck

5 Nested Surface Coils for Multinuclear NMR 39
Arthur W. Magill and Rolf Gruetter

6 Quadrature Transverse Electromagnetic (TEM) Surface Coils 51
Nikolai I. Avdievich

Part B: Array Coils 63

7 Receiver Loop Arrays 65
Steven M. Wright

8 Coil Array Design for Parallel Imaging: Theory and Applications 81
Daniel K. Sodickson, Michael A. Ohliger, Riccardo Lattanzi and Graham C. Wiggins

9 Transceiver Loop Arrays 101
Randy Duensing

10 Characterization of Multichannel Coil Arrays on the Benchtop 111
Mark A Griswold

Part C: Volume Coils 121

11 Birdcage Volume Coil Design 123
Nicola De Zanche

12 Double–Tuned Birdcage Coils: Construction and Tuning 137
Joseph Murphy–Boesch

13 TEM Body Coils 147
J. Thomas Vaughan

14 TEM Transceiver Head Array Coils for Ultra High Magnetic Fields 169
Gregor Adriany

15 TEM Arrays, Design and Implementation 175
Carl Snyder

16 Transverse Electromagnatic (TEM) Coils for Extremities 185
Nikolai I. Avdievich

17 Antennas as Surface Array Elements for Body Imaging at Ultra–high Field Strengths 197
A. J. E. Raaijmakers and C. A. T. van den Berg

Part D: Special Purpose Coils 209

18 Catheter Coils 211
Ergin Atalar

19 Microcoils 225
Andrew G. Webb

20 Cryogenic and Superconducting Coils for MRI 233
Sven Junge

21 Litz Coils for High Resolution and Animal Probes, Especially for Double Resonance 245
F. David Doty, George Entzminger Jr

22 Millipede Coils 259
Ernest W. H. Wong

Part E: Coil Interface Circuits 269

23 Receiver Design for MR 271
David I. Hoult

24 Radiofrequency Power Amplifiers for NMR and MRI 299
Daniel P. Myer

25 Impedance Matching and Baluns 315
David M. Peterson

Part F: Coil Modeling and Evaluation 325

26 Radiofrequency MRI Coil Analysis: A Standard Procedure 327
Rostislav A. Lemdiasov, Reinhold Ludwig

27 Practical Electromagnetic Modeling Methods 339
Jian–Ming Jin

28 Radiofrequency Fields and SAR for Bird Cages 363
Tamer S. Ibrahim

29 RF Field Modeling for Double–Tuned Volume Coils 377
Wanzhan Liu

30 Radiofrequency Fields and SAR for Transverse Electromagnetic (TEM) Surface Coils 387
Can Eyup Akgun

31 TEM Coil Fields and SAR 397
Jinfeng Tian

Part G: RF Safety 407

32 RF Device Safety and Compatibility 409
John Nyenhuis

33 Radiofrequency Heating Models and Measurements
Devashish Shrivastava, J. Thomas Vaughan 425

Index 437