A Selective-Echo Method for Chemical-Shift Imaging of Two-Component Systems

✍ Scribed by Rex E. Gerald II; Anatoly O. Krasavin; Robert E. Botto

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 304 KB
• Volume: 123
• Category: Article
• ISSN: 1064-1858
• DOI: 10.1006/jmra.1996.0236

✦ Synopsis

A simple and effective method for selectively imaging either one distinct categories. In the first category are frequency-selecof two chemical species in a two-component system is presented tive techniques, for either excitation or saturation. These and demonstrated experimentally. The pulse sequence employed, techniques make use of three types of pulse sequences: simselective-echo chemical-shift imaging (SECSI), is a hybrid (freple, long soft pulses (7, 8); complex shaped pulses (9); quency-selective/T 1 -contrast) technique that is executed in a short and composite pulse trains (10, 11). The second category period of time, utilizes the full Boltzmann magnetization of each consists of pulsed methods that utilize differences in spinchemical species to form the corresponding image, and requires lattice relaxation (T 1 ) as a means for obtaining contrast. only hard pulses of quadrature phase. This approach provides a In the latter category, selectivity depends on there being a direct and unambiguous representation of the spatial distribution significant difference in the T 1 values of resonances for nuof the two chemical species. In addition, the performance characteristics and the advantages of the SECSI sequence are compared clei in different chemical environments. There are also other on a common basis to those of other pulse sequences. ᭧ 1996 Academic techniques that do not fit into either of these categories, such Press, Inc.

as the stimulated-echo methods (12)(13)(14).

The two principal drawbacks of many schemes for selective excitation or saturation are the complexity of the pulse