Local Coil Sensitivity Profile Determination Using Ultrashort Echo Times

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Solution Overview

Problem

Current methods for determining sensitivity profiles of local coils in magnetic resonance technology involve noise-exposure due to gradient echo sequences, leading to signal inhomogeneities in MR images.

Innovation Solution

A method using ultrashort echo time pulse sequences, such as PETRA or zTE, for acquiring measurement data sets with local coils, reducing noise exposure and dephasing errors, allowing for silent operation and improved image homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gradient echo sequences are used to determine sensitivity profiles, then sensitivity distribution can be measured, but noise exposure increases significantly

Engineering Contradiction:

Improvesensitivity distribution measurementVSAvoidnoise exposure

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the timing parameters of the pulse sequence by using ultrashort echo times (TE < 0.5 ms) to acquire measurement data before significant dephasing occurs. This parameter change allows sensitivity profile determination without requiring loud gradient switching, thereby reducing noise exposure while maintaining measurement capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional gradient echo sequence mechanism with an ultrashort echo time sequence mechanism. Instead of relying on gradient switching to generate echo signals (which produces noise), the invention uses rapidly acquired data with minimal gradient activity, substituting the noise-generating mechanism with a quieter alternative that achieves the same measurement goal

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If gradient echo sequences are used, then sensitivity profiles can be acquired, but dephasing errors increase

Engineering Contradiction:

Improvesensitivity profile acquisitionVSAvoidsignal accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent performs the measurement action preliminarily by acquiring the sensitivity profile data before significant dephasing can occur. By using ultrashort echo times, the measurement is completed in the time window before magnetic spin dephasing degrades signal accuracy, thus preventing rather than correcting dephasing errors

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent rushes through the measurement process by acquiring data extremely quickly with ultrashort echo times. The measurement is completed so rapidly that the dephasing process is essentially skipped over, preventing accumulation of phase errors that would otherwise degrade signal accuracy

Inventive Principle:

Principle #21Skipping (Rushing through)

3Power

If local coils are placed near the subject to improve signal-to-noise ratio, then signal reception improves, but signal inhomogeneities increase

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidimage homogeneity

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

The patent performs preliminary measurement of the sensitivity distribution using ultrashort echo times before actual imaging. This preliminary sensitivity map is then used to correct the inhomogeneities in subsequent images, allowing local coils to be placed close to the subject for improved signal-to-noise ratio while maintaining image homogeneity through correction

Inventive Principle:

Principle #10Preliminary action

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 the determination of sensitivity profiles with reduced noise exposure and improved image homogeneity, minimizing signal inhomogeneities and artifacts in MR images.

Implementation Method 1

in the determination of the sensitivity profile, errors due to dephasings are avoided as best as possible by the acquisition of the measurement data sets with a pulse sequence with ultrashort echo times (i.e. in particular echo times TE shorter than 0.5 ms)

Methodology Applied

Scientific EffectDephasing:

Implementation Method 2

The sequence that is used is very loud. Usually, noise levels of well over 90 dB(A) occur due to the gradients to be switched

Methodology Applied

Scientific EffectGradient switching noise:

Data Source

PatentUS9915718B2Method and magnetic resonance apparatus to determine a sensitivity profile of a local coil

Publication Date: 2018.03.13 SIEMENS HEALTHINEERS AG

AI summary

In a method for the determination of sensitivity profiles of local coils in the acquisition of magnetic resonance data, a first measurement data set of an examination area is acquired with a first acquisition coil, a second measurement data set of the examination area is acquired with a local coil, and a sensitivity profile of the local coil that is used is determined on the basis of the first measurement data set and the measurement data set. The first measurement data set and the second measurement data set are acquired using a pulse sequence with ultrashort echo times. In the determination of the sensitivity profile, errors due to dephasings are avoided as best as possible by the acquisition of the measurement data sets with a pulse sequence with ultrashort echo times (i.e. in particular echo times TE shorter than 0.5 ms); in particular, the dephasings are smaller given these echo times than in the case of gradient echo (GRE)-based pulse sequences.