Abstract

As a medical imaging modality, MRI boasts its unparalleled versatility and excellent fundamental safety. MRI can generate a large variety of soft tissue contrasts, many of which are endogenous, and the electromagnetic energy employed for imaging is relatively transparent to biological tissue. The systems engineering for an MRI scanner is well developed and mature, with over 35,000 scanners worldwide producing more than 10,000 patient scans every hour. Over the past decades, steady progress has been made in MRI engineering for faster scans, higher spatial resolutions, and more compact devices for the function. In fact, many breakthrough technologies were first announced in one of the ISMRM annual meetings. Most technical and clinical users of MRI work with the host computer interface, RF receive coils, and/or pulse sequence development environment without much exposure to various hardware subsystems behind the cover of the scanner. These include the main magnet, the gradient coils, and the RF transmit coil(s) along with their control and power electronics. More recently, compensating for imperfections in the static field (B0 shimming), the RF field (B1 shimming), and the gradient waveforms (eddy current compensation) has become more and more important as the scanners are pushed for higher performance. Understanding the inner workings and interactions of these subsystems will help understand the limits of everyday imaging parameters and identify potential areas of future improvements. This presentation will cover the basic operational principles of field-generating and signal detection units of an MRI scanner, their interconnections, and important design limitations that come from engineering and physiological constraints. This course thus provides a ground work for the following lectures in this session on more details of individual subsystem engineering.

Acknowledgements

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References

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