Activity on this project during reporting year 2009-2010 was marked by the transition to ultra high field MRI. Two new human-size MRI systems were purchased to allow the study of brain anatomy and function at 7 and 11.7 Tesla respectively. This involved significant planning efforts. The 7 Tesla system, which is self shielded and can be sited in standard (lower field) MRI bays, arrived in August 2010 and will replace the current prototype 7 T system;in early 2011 we expect to install the 11.7 T which will be the worlds highest field strength human system. Once operational, which will require significant development efforts, we expect this system to allow brain studies with improved contrast and resolution. Technological progress was made in a number of areas. Specifically, improved methods were developed to interpret frequency shift images obtained with susceptibility-weighted imaging at 7T. This has led to the reconstruction of quantitative susceptibility maps of the human brain, which provide complementary and potentially superior information compared to conventional contrast mechanisms such as NMR relaxation times. In another development, novel electro-magnetic (EM) field simulations methods were developed wit the goal of rapidly calculating tissue heating associated with the deposition of EM radiation during MRI scanning. This technology is critical for full exploitation of the capabilities of high field MRI systems. In a third project, a new method was developed to non-invasively assess cerebro-vascular reactivity in human brain. This method, based on a specific breathing-paradigm, is expected to facilitate studies in patients with compromised cardio-vascular systems.
| Gudino, Natalia; de Zwart, Jacco A; Duan, Qi et al. (2018) Optically controlled on-coil amplifier with RF monitoring feedback. Magn Reson Med 79:2833-2841 |
| Liu, Jiaen; de Zwart, Jacco A; van Gelderen, Peter et al. (2018) Effect of head motion on MRI B0 field distribution. Magn Reson Med 80:2538-2548 |
| van Gelderen, Peter; Jiang, Xu; Duyn, Jeff H (2017) Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI. Magn Reson Med 77:2174-2185 |
| Jiang, Xu; van Gelderen, Peter; Duyn, Jeff H (2017) Spectral characteristics of semisolid protons in human brain white matter at 7 T. Magn Reson Med 78:1950-1958 |
| Gudino, Natalia; Duan, Qi; de Zwart, Jacco A et al. (2016) Optically controlled switch-mode current-source amplifiers for on-coil implementation in high-field parallel transmission. Magn Reson Med 76:340-9 |
| Duan, Qi; Nair, Govind; Gudino, Natalia et al. (2015) A 7T spine array based on electric dipole transmitters. Magn Reson Med 74:1189-97 |
| van Gelderen, Peter; Mandelkow, Hendrik; de Zwart, Jacco A et al. (2015) A torque balance measurement of anisotropy of the magnetic susceptibility in white matter. Magn Reson Med 74:1388-96 |
| Duan, Qi; Duyn, Jeff H; Gudino, Natalia et al. (2014) Characterization of a dielectric phantom for high-field magnetic resonance imaging applications. Med Phys 41:102303 |
| Duyn, Jeff H (2014) Frequency shifts in the myelin water compartment. Magn Reson Med 71:1953-5 |
| Duyn, Jeff H; Barbara, Thomas M (2014) Sphere of Lorentz and demagnetization factors in white matter. Magn Reson Med 72:1-3 |
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