Diffusion detection by means of magnetic resonance

• US 6,265,872 B1
• Filed: 08/18/1998
• Issued: 07/24/2001
• Est. Priority Date: 08/19/1997
• Status: Expired due to Term

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Heid, Oliver
• Primary Examiner(s): Patidar, Jay
• Assistant Examiner(s): Vargas, Dixomara
• Application Number:
  US09/135,165
• Time in Patent Office: 1,071 Days
• Field of Search: 324/307, 324/306, 324/309, 324/303, 324/300
• US Class Current: 324/307
• CPC Class Codes: G01R 33/56341 Diffusion imaging

Abstract

Diffusion detection by means of magnetic resonance is accomplished by obtaining a spin echo signal in a readout window by exciting a nuclear resonance signal with a first radio-frequency pulse and by refocusing by at least two other radio-frequency pulses; and activating diffusion gradient pulses of alternating polarity in at least one direction prior to the readout window. The gradient time integrals of the diffusion gradient pulses are different from each other.

Claims

1. A method for diffusion detection by magnetic resonance comprising the steps of:

obtaining a spin echo signal in a readout time window by excitation of a nuclear resonance signal with a first radio-frequency pulse and refocusing by at least a second radio-frequency pulse and a third radio-frequency pulse;

activating respective gradient pulses between each of the radio-frequency pulses and prior to the readout window, and alternating the polarity of the respective gradient pulses from gradient pulse-to-gradient pulse; and

said gradient pulses in totality having a gradient time integral of zero from a time of said excitation to the readout window the gradient time integrals of at least two of said gradient pulses being different.

2. A method as claimed in claim 1 wherein the step of actuating respective gradient pulses comprises:

activating a gradient pulse of a first polarity between the first radio-frequency pulse and the second radio-frequency pulse;

activating two gradient pulses of differing polarity between the second radio-frequency pulse and the third radio-frequency pulse, beginning with a polarity that is opposite the first polarity;

activating another gradient pulse of the first polarity between the third radio-frequency pulse and the readout window.

3. A method as claimed in claim 1 comprising the additional steps of:

spatially encoding the spin echo signal by activating a phase-encoding gradient prior to the readout time window; and

activating a readout gradient during the readout time window.