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. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Conventional contrast in magnetic resonance (MR) images is derived 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 T1¿ has shown 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 T1¿ imaging shows both an augmented BOLD signal and improved response to indirectly detected metabolic 17O water. The purpose of this subproject is to develop techniques for T1¿-weighted imaging emphasizing both novel methods and translation to the clinic. Novel Methods 1. Correction for B1 field heterogeneity by an off-resonance rotary echo magnetization preparation pulse sequence. 2. Correction for B0 and B1 field heterogeneity 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. T1¿-prepared centrically reordered multiple gradient echo (balanced and spoiled) for rapid 3D T1¿-weighted image acquisition. 2. Integrated partial Fourier and parallel imaging k-space acquisition for image blur reduction and reduced acquisition time. 3. Decreased imaging time using T1¿-prepared k-space weighted image contrast (T1¿-KWIC) for view sharing of radial projections during k-space acquisition.