Frequency-Sweep MRI Phase Encoding for Echo Drift Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Single-sided MRI scanners face challenges due to a changing field of view along the Z axis, drifting echoes, and truncation of k-space, which result in blurring and limited image quality.

Innovation Solution

A method involving a frequency sweep excitation pulse with phase encoding during the sweep and precise tuning of phase accumulation to compensate for the varying gradient strength, ensuring consistent field of view and echo alignment across slices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a surface gradient coil is used with a single-sided scanner, then imaging without an enclosed bore is achieved, but the field of view changes along the Z axis causing blurring and limited image quality

Engineering Contradiction:

Improveimaging accessibilityVSAvoidimage quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by using a frequency sweep excitation pulse that varies the excitation frequency across the slab, and by adjusting the phase encoding gradient strength to compensate for the inherent gradient variations. This resolves the contradiction by dynamically changing parameters (frequency, phase encoding gradient) to maintain consistent field of view and image quality across all slices despite the surface gradient coil's inherent limitations.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If phase encoding is performed with conventional pulses, then k-space truncation occurs, but image resolution and SNR are limited

Engineering Contradiction:

Improvek-space coverageVSAvoidimage resolution

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent employs dynamics by using a frequency sweep excitation pulse where the frequency changes continuously over time during the excitation process. This dynamic frequency modulation, combined with phase encoding, allows for complete k-space coverage without truncation while maintaining high image resolution and signal-to-noise ratio, resolving the contradiction between k-space coverage and image quality.

Inventive Principle:

Principle #15Dynamics

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

This approach allows for high-quality axial images by maintaining consistent slice dimensions and preventing echo drift, thereby enhancing image resolution and SNR without k-space truncation.

Implementation Method 1

magnetic resonance imaging

Methodology Applied

Scientific EffectNuclear Magnetic Resonance:

Implementation Method 2

transmitting a frequency sweep excitation pulse comprising a low-to-high frequency sweep

Methodology Applied

Scientific EffectFrequency sweep excitation:

Implementation Method 3

phase encoding during the frequency sweep excitation pulse

Methodology Applied

Scientific EffectMagnetic field gradient: Magnetic Field

Data Source

PatentUS20250347761A1Phase encoding with frequency sweep pulses for magnetic resonance imaging in inhomogeneous magnetic fields

Publication Date: 2025.11.13 PROMAXO INC

AI summary

Single-sided MRI apparatuses, systems, and methods are disclosed. A method can include transmitting a frequency sweep excitation pulse comprising a low-to-high frequency sweep; phase encoding during the frequency sweep excitation pulse; and tuning the amount of phase accumulated during the frequency sweep excitation pulse from adjacent slices in the slab. The frequency sweep excitation pulse can be a chirp pulse. Encoding in this way can prevent spin echoes from drifting and prevent k-space truncation in certain instances. Moreover, the resultant images can be combined more efficiently.