University of Rochester

Jianhui Zhong

Wingchi Edmund Kwok

Saara Marjatta Sofia Totterman

Zhong Chen

Zhigang You

An RF coil construction for MRI is disclosed. The construction includes a device for cryogenically cooling receiver coils, at least two coil elements being cryogenically cooled by the device and forming an array. Each coil element includes at least two capacitors for tuning and matching the coil element. The construction also includes a circuit connected to each coil element for decoupling the coil element from the transmitter coil(s), and also for decoupling among coil elements.

Cryogenically cooled phased array RF receiver coil for magnetic resonance imaging

In magnetic resonance imaging, a pulse sequence is used to obtain both water-only and fat-only signals within a single acquisition time. Pulses and readout gradients are applied to take a proton-density-weighted image of the water, a proton-density-weighted image of the fat, and a T2-weighted image of the water. Between the first water readout gradient and the fat readout gradient, a spoiling gradient is applied to spoil the first water echo. Between the fat readout gradient and the second water readout gradient, a refocusing gradient is applied to refocus the second water echo. The proton-density-weighted images of water and fat are combined to form water-plus-fat images free of in-plane and through-plane chemical-shift artifacts.

Interleaved water and fat dual-echo spin echo magnetic resonance imaging with intrinsic chemical shift elimination

In nuclear magnetic resonance imaging of the human brain or the like, multiple quantum coherences, such as intermolecular double quantum coherence (iDQC) between water molecules, are used for soft tissue contrast. A group of pulse sequences are used in which, (a) The standard &bgr;&equals;&pgr;/2 pulse in the original CRAZED sequence is replaced with a &pgr;/3 pulse. The maximum signal derived from iDQCs is increased by a factor of 3{square root over (3)}/4. (b) The position of the acquisition window is adjusted, and a large acquisition window (small bandwidth) is used to sample a broad range of time-domain signals. (c) Receiver dynamic range is optimized. (d) A two-step phase cycle scheme for iDQC-encode gradients is designed to remove additional undesired coherence pathways.

Intermolecular multiple-quantum coherence MR imaging in humans

A magnetic imaging device, such as an MR scanner, is used to provide a modified three-dimensional gradient echo sequence having a spatial-spectral excitation in which phase-encoding lines are interleaved for the excitation of water and of fat. The phase-encoding lines are spaced by an interval equal to half of the repetition time. The resulting data are sorted for the reconstruction of water-only and fat-only images, which are realigned and combined to form water-fat combined images free of chemical shift artifacts.

System and method for three-dimensional interleaved water and fat image acquisition with chemical-shift correction

A technique for MRI or the like employs optimized orthogonal gradients. For a device having a peak physical magnetic field gradient strength G,, the gradients are optimized if, in physical space, one gradient has a value &minus;0.5G,while the two gradients orthogonal thereto have the value G,. That is equivalent to an optimized orthogonal gradient space in which one gradient has a value 1.5G,while the two gradients orthogonal thereto have the value zero. The gradients are cycled over a sequence of six gradient pulses to provide enough data to calculate the diffusion tensor.

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Jianhui Zhong