TECHNIQUES FOR T1P-WEIGHTED IMAGING

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Conventional contrast in magnetic resonance (MR) images derives from the 1H magnetic relaxation properties of tissues. Variations in longitudinal magnetic relaxation (T1) and transverse magnetic relaxation (T2) distinguish the healthy and pathological states. An unconventional contrast mechanism based on the rotating frame spin-lattice relaxation time T1p shows sensitivity to the diseased states of the human breast, early acute cerebral ischemia in rats, cartilage degeneration during osteoarthritis, posttraumatic cartilage injury and narrowing of lumbar intervertebral discs associated with degenerative disc disease. In addition, functional T1p imaging shows both an augmented BOLD signal and improved response to indirectly detected metabolic oxygen-17 water. The purpose of this subproject is to develop techniques for T1p-weighted imaging emphasizing both novel methods and translation to the clinic. Novel Methods: 1. Correction for B1 field inhomogeneity by an off-resonance rotary echo magnetization preparation pulse sequence. 2. Correction for B0 and B1 field inhomogeneity by an integrated spin echo and spin lock magnetization preparation pulse sequence. 3. Steady-state spin lock techniques by integrated spin lock and balanced gradient echo pulse sequence design. Methods for Translation to the Clinic: 1. T1p-prepared, centrically reordered balanced gradient echo imaging for rapid 3D T1p-weighted image acquisition. 2. Motion correction by navigator echoes. 3. Integrated partial Fourier and parallel imaging kspace acquisition for image blur reduction and reduced acquisition time.