Flat Plate Gradient Coils for Breast MRI Access

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Solution Overview

Problem

Current magnetic resonance tomography (MRT) systems face limitations in generating steep and fast gradients, particularly for diffusion-weighted imaging of the female breast, due to biological stimulation limits and the 'pot-shaped' local gradient coil design which restricts access for biopsies.

Innovation Solution

A method using multiple antenna elements to determine SAR values by calculating cross correlation matrices and integrating flat plate gradient coils that allow for faster and steeper gradients, maintaining lateral and medial access for breast imaging, and optionally extending to the z-direction with additional coils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If steep and fast gradients are used for diffusion-weighted imaging, then imaging quality is improved, but electrical currents are induced in nerve tracts exceeding biological stimulation limits

Engineering Contradiction:

Improveimaging qualityVSAvoidelectrical currents in nerve tracts

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The gradient system is divided into multiple independent gradient coils (first gradient coil and second gradient coil) that can be controlled separately. This segmentation allows the gradients to be applied in a controlled manner to achieve the desired imaging quality while staying within safety limits by managing the temporal and spatial distribution of gradient changes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic gradient application through alternating polarity gradients in the first and second gradient coils. The gradients are applied in a periodic fashion with controlled duty cycles, allowing steep gradients to be used for imaging while the periodic nature and controlled timing prevent continuous electrical stimulation of nerve tracts.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If a pot-shaped local gradient coil is used, then local gradient strength is improved, but lateral and medial access for biopsies is restricted

Engineering Contradiction:

Improvelocal gradient strengthVSAvoidaccess for biopsies

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The single pot-shaped coil is segmented into multiple flat plate gradient coils arranged in a specific geometry. These separate plates can be positioned to provide gradient fields in the breast imaging region while leaving the lateral and medial sides accessible for biopsy procedures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a three-dimensional pot-shaped coil enclosing the breast to a planar arrangement of flat plates positioned around the breast. This dimensional change from a enclosing structure to a planar configuration maintains the necessary gradient field strength while opening up access paths from the lateral and medial directions for biopsy operations.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables faster and steeper gradients for improved diffusion-weighted imaging while maintaining access for biopsies by using flat plate gradient coils that can be integrated with RF coils and biopsy devices, enhancing imaging quality and biopsy coordination.

Implementation Method 1

A field gradient in the X-direction can advantageously be generated that has the form of an inverted 'V' and whose maximum lies in the middle between the breasts

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction