MEIR SHINNAR
Medical Practice in Cynwyd, PA

5153515, Oct 6, 1992

Feb 14, 1991

7/655077

John S. Leigh - Philadelphia PA
Meir Shinnar - Bala Cynwyd PA

Trustees of the University of Penna. - Philadelphia PA

G01R 3320

324307

Methods of constructing pulse sequences to selectively excite frequency bands in NMR imaging, spectroscopic and optical systems are disclosed. In preferred embodiments, selective. pi. /2,. pi. , and refocusing hard and soft pulses are constructed for perturbing the spins of the system. In NMR imaging, for example, the desired magnetization is written as an (N+1)th order Fourier series in. omega. t, where. omega. is the off-resonance frequency. In addition, if all pulses have the same phase, then the z magnetization is known to be symmetric in frequency, and the resulting hard pulse sequence can be written as an Nth order Fourier cosine series. Given this Fourier series representing the desired z magnetization, an inversion may be used to determine the hard pulse sequence of N pulses which will actually yield the desired response. In particular, if one starts with a specification of a desired z magnetization not as a Fourier series in. omega. t, but rather as having certain desired values over several frequency ranges, the techniques of finite impulse response filters may be applied to yield the desired Fourier series representing the z and xy magnetizations.

5217016, Jun 8, 1993

Apr 15, 1991

7/685915

Leon Axel - Philadelphia PA
Meir Shinnar - Bala Cynwyd PA

The trustees of the University of Pennsylvania - Philadelphia PA

A61B 5055

1286532

A technique for generating "optimal" radio frequency pulses for use in creating SPAMM imaging stripes. The MR imaging operator is given an opportunity to select the desired stripe parameters for the SPAMM imaging stripe so that the resulting SPAMM imaging stripe will have the desired narrowness, sharpness, flatness and the like. These parameters are then used by an optimal pulse generating system of the invention to generate the input radio frequency pulse sequence which will produce the desired stripes. This technique allows a large family of pulse sequences with fairly similar performance to be generated by simply adjusting the relative weightings of criteria such as the narrowness, sharpness, flatness and the like for the SPAMM stripes.

5572126, Nov 5, 1996

Jul 28, 1994

8/282220

Meir Shinnar - Bala Cynwyd PA

University of Pennsylvania - Philadelphia PA

G01V 300, G01V 314

324314

A technique has previously been described for generating optimal RF pulse sequences using finite impulse response filter techniques to calculate the Fourier series which would yield the desired z and xy magnetizations in a magnetic resonance imaging device. Such a technique is now extended to allow for control of the input pulse shape as well as the frequency response. Since the peak power is limited by the amplifier power and the total energy of the pulse is limited by the specific absorption rate (SAR) of the tissue or sample, it is desired to limit the peak power and total energy of the input pulse without degrading the resulting excitation. This is accomplished by recognizing that the total energy of the pulse is encoded in the lowest order Fourier series coefficients of the frequency response and then specifying the total energy of the pulse as a design parameter to the RF pulse synthesis algorithm. Peak power of the pulse may also be limited by selecting roots for. beta. (. omega. ), where M. sub. z (. omega. )=.

5471991, Dec 5, 1995

Nov 16, 1993

8/152526

Meir Shinnar - Bala Cynwyd PA

Trustees of the University of Pennsylvania - Philadelphia PA

A61B 50452

128705

System and method for determining characteristics of a system ideally represented by fractals by using wavelet analysis to determine whether regions of a signal derived from the fractal system are self affine, in particular, using wavelet analysis of an ECG signal to determine whether a patient is at risk for ventricular tachycardia or sudden death.