Magnetic Resonance Imaging Device and Method for Operating a Magnetic Resonance Imaging Device

• US 20080272784A1
• Filed: 06/24/2005
• Published: 11/06/2008
• Est. Priority Date: 06/29/2004
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Harvey, Paul Royston, Peeren, Gerardus Nerius
• Application Number:
  US11/571,002
• Publication Number:
  US 20080272784A1
• Time in Patent Office: Days
• US Class Current: 324/318
• CPC Class Codes: G01R 33/385 using gradient magnetic field coils

Abstract

The present invention relates to a magnetic resonance imaging (MRI) device and to a method for operating it. The basic components of an MRI device are the main magnet system (2) for generating a steady magnetic field, the gradient system (3) with at least one gradient coil, the RF system and the signal processing system. According to the present invention, the gradient coil is split into sub-coils (S1, S2) at least in the direction of the steady magnetic field. By doing so, the amplitude of the non-imaging component of the gradient field in the vicinity of the patient is reduced, leading to reduced peripheral nerve stimulation and thus enhanced image quality.

Claims

1. A magnetic resonance imaging device, comprising at least:

a main magnet system for generating a steady magnetic field in a measuring space of the magnetic resonance imaging device;

a gradient system with at least one gradient coil for generating a magnetic gradient field in said measuring space;

wherein the magnetic gradient field has at least one component that is perpendicular to the steady magnetic field, wherein the gradient coil is split into sub-coils at least in the direction of the steady magnetic field such that the magnetic gradient field component perpendicular to the steady magnetic field is reduced in a least one region of the measuring space.

2. A magnetic resonance imaging device according to claim 1, wherein each sub-coil is driven by a separate amplifier.

3. A magnetic resonance imaging device according to claim 1, wherein the sub-coils are driven by one or more amplifiers and connected in a parallel configuration.

4. A magnetic resonance imaging device according to claim 1, wherein the sub-coils are driven by one or more amplifiers and connected in a series configuration.

5. A magnetic resonance imaging device according to claim 2 wherein at least one sub-coil operates with a current offset in addition to the time dependent current needed for generating the magnetic gradient field.

6. A magnetic resonance imaging device according to claim 2 wherein the gradient coil is divided into two sub-coils, wherein both sub-coils operate with a current offset in addition to the time dependent current needed for generating the magnetic gradient field, and wherein the one sub-coil operates with the inverse current offset of the other sub-coil.

7. A magnetic resonance imaging device according to claim 3, wherein the sub-coils are arranged to permit for switching between parallel and series configuration.

8. A magnetic resonance imaging device according to claim 5, wherein the device comprises a processing unit to calculate, before taking an image, the best sub-coil configuration and/or the best current offset for the required image quality while minimizing the peripheral nerve stimulation to be expected in the object to be examined.

9. A magnetic resonance imaging device according to claim 1, wherein the sub-coils are independently shielded.

10. A method for operating a magnetic resonance imaging device as claimed in claim 1, comprising the steps of:

calculating the best sub-coil configuration and/or best current offset for the required image quality while minimizing the peripheral nerve stimulation to be expected in the object to be examined before making an exposure;

generating the magnetic gradient field with a reduced magnetic field component perpendicular to the steady magnetic field by using the calculated best sub-coil configuration and/or the calculated best current offset.