Magnetization transfer imaging (MTI) is an alternative method for obtaining increased conspicuity of enhancement using only a single dose of contrast. MTI uses off-frequency RF-pulses to saturate the "bound pool" of macromolecules. Because contrast enhancement is due to a direct water-gadolinium interaction and not mediated by macromolecules, it is not affected by the MT pulse. Contrast enhancing areas are rendered more conspicuous on MT images, rivaling that of triple dose contrast.
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In addition to triple dose contrast and MT imaging, the use of subtraction imaging was at one time considered a possible method for improving detection of contrast enhancement. However, patient motion between the pre- and post-contrast images often creates artifacts that can resemble marginal contrast enhancement. Registration programs have improved, but have not completely eliminated this problem.
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What is magnetization transfer?
How is contrast generated by magnetization transfer? Also, what are MTI, MTC, and MTR?