Multi-pulse line narrowing

Imaging with multi-pulse line narrowing 110... 

Imaging with multi-pulse line narrowing has been realized in different variants. These include time-invariant gradients, oscillating gradients, pulsed gradients, and CRAMPS. Each of these variants is addressed in the following. 

A solid-state variant of the DANTE sequence (Fig. 5.3.15) is obtained by replacing the rf pulses and the free precession periods of the original sequence by line-narrowing multi-pulse sequences [Carl, Corl, Flepl, Hep2J. Such DANTE sequences can be used for selective excitation in solid-state spectroscopy (cf Fig. 7.2.8) and for slice selection in solid-state imaging (Fig. 5.3.16). 

In the following, some aspects of multi-pulse excitation are reviewed which are relevant for space encoding. The effects of time-invariant and pulsed gradients are addressed as well as methods to increase the line-narrowing efficiency through second averaging and CRAMPS (cf. Section 3.3.4). 

Multi-pulse sequences for line narrowing based on magic echoes represent another possibility to realize time-suspension. Such sequences are less difficult to implement than pulse sequences based on solid echoes and consequently, appear to be more popular for use in imaging. Therefore, they are treated separately in Section 8.8. 

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