151. Use of Navigator Echoes in Cardiovascular Magnetic Resonance and Factors Affecting Their Implementation
- Author
-
Jennifer Keegan and David Firmin
- Subjects
Alternative methods ,medicine.medical_specialty ,medicine.diagnostic_test ,Computer science ,business.industry ,SIGNAL (programming language) ,Measure (physics) ,Magnetic resonance imaging ,Column (database) ,Motion (physics) ,Position (vector) ,medicine ,Computer vision ,Medical physics ,Enhanced Data Rates for GSM Evolution ,Artificial intelligence ,business - Abstract
Although many cardiovascular magnetic resonance (CMR) clinical applications have been developed with breath-hold scanning, some still require more data to be acquired with alternative methods of overcoming the problem of respiratory motion. This chapter provides a complete overview of CMR navigator imaging methods for the measurement of respiratory motion and the approaches to correcting for it. The first navigator echoes were 1D images of a column of tissue orientated in the head-foot direction through the right hemi-diaphragm showing an edge of signal that gave a measure of the respiratory position. Initially these were acquired every cardiac cycle and were used to feedback to the patient his or her respiratory position so that he or she could achieve a consistent breath-hold position in order to build up large data sets over multiple breath-holds. Following this, free-breathing approaches have been developed with increasingly more sophisticated algorithms to enable more efficient use of the data. In addition, this chapter describes more recently introduced “self-navigators” where part of the image data is used to measure the motion. Finally, because of the complexity of respiratory-related cardiac motion, there has been an interest in developing modeling methods, which are described toward the end of the chapter.
- Published
- 2010