MODIFIED JEENER SOLID-ECHO PULSE SEQUENCES FOR THE MEASUREMENT OF THEPROTON DIPOLAR SPIN-LATTICE RELAXATION-TIME (T-1D) OF TISSUE SOLID-LIKE MACROMOLECULAR COMPONENTS

Modified Jeener solid-echo pulse sequences are proposed for the measur ement of the proton dipolar spin-lattice relaxation time, T-1D, of mot ionally restricted (solid-like) components in the presence of mobile m olecular species, such as encountered in biological tissue. A phase-cy cled composite-pulse sequence was used for detection of the dipolar si gnal and cancellation of the Zeeman signal. A homospoil gradient pulse was added to the Jeener echo pulse sequence to enhance dephasing of t he transverse magnetization components of mobile species, thereby aidi ng in elimination of the Zeeman signal during dipolar signal acquisiti on. A modified Jeener echo sequence incorporating water suppression is also proposed as a means to further depress the Zeeman signal arising from mobile components. The modified Jeener echo sequences were succe ssfully used for the measurement of proton T-1D values of solid 2,6-di methylphenol and Sephadex gels of differing degrees of cross linking a nd hydration. (C) 1994 Academic Press, Inc.