Modified Jeener solid-echo pulse sequences for the measurement of the proton dipolar spin-lattice relaxation time (T1D) of tissue solid-like macromolecular components

Abstract Modified Jeener solid-echo pulse sequences are proposed for the measurement of the proton dipolar spin-lattice relaxation time, T 1D , of motionally restricted (solid-like) components in the presence of mobile molecular species, such as encountered in biological tissue. A phase-cycled composite-pulse sequence was used for detection of the dipolar signal and cancellation of the Zeeman signal. A homospoil gradient pulse was added to the Jeener echo pulse sequence to enhance dephasing of the transverse magnetization components of mobile species, thereby aiding in elimination of the Zeeman signal during dipolar signal acquisition. 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 successfully used for the measurement of proton T 1D values of solid 2,6-dimethylphenol and Sephadex gels of differing degrees of cross linking and hydration.