Zhong Dian Chen

US Patent:

6528997, Mar 4, 2003

Filed:

Mar 20, 2001

Appl. No.:

09/811831

Inventors:

Jianhui Zhong - Pittsford NY
Zhong Chen - Rochester NY
Wingchi E. Kwok - Rochester NY

Assignee:

University of Rochester - Rochester NY

International Classification:

G01V 300

US Classification:

324307, 324309

Abstract:

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 = /2 pulse in the original CRAZED sequence is replaced with a /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.

US Patent:

62885405, Sep 11, 2001

Filed:

May 19, 2000

Appl. No.:

9/573940

Inventors:

Zhong Chen - Rochester NY
Jianhui Zhong - Pittsford NY
Wingchi Edmund Kwok - Rochester NY

Assignee:

University of Rochester - Rochester NY

International Classification:

G01V 300

US Classification:

324300

Abstract:

A technique for MRI or the like employs optimized orthogonal gradients. For a device having a peak physical magnetic field gradient strength G. sub. 0, the gradients are optimized if, in physical space, one gradient has a value -0. 5G. sub. 0 while the two gradients orthogonal thereto have the value G. sub. That is equivalent to an optimized orthogonal gradient space in which one gradient has a value 1. 5G. sub. 0 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.