T2*-weighted MRI CSF Suppression for Cortical Lesion Detection

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Solution Overview

Problem

Current MRI technologies at standard clinical magnetic field strengths, such as 3T, are poorly sensitive to cortical lesions, especially subpial lesions, due to low signal-to-noise ratio and close proximity to cerebrospinal fluid, making it difficult to visualize and detect these lesions accurately.

Innovation Solution

A T2*-weighted MRI sequence with CSF suppression using a 3D-T2*-weighted multi-shot acquisition and T2-prepared inversion pulse, combined with IR-SWIET and optional MP2RAGE or FLAIR sequences, to enhance lesion contrast and visibility, particularly through CSF-nulling and optimal parameter selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If standard clinical MRI field strength (3T) is used, then accessibility and availability are improved, but sensitivity to cortical lesions deteriorates

Engineering Contradiction:
ImproveaccessibilityVSAvoidsensitivity to cortical lesions
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by modifying the MRI sequence parameters specifically for T2*-weighted imaging at 3T, including optimizing echo time (TE), repetition time (TR), and using specific inversion recovery parameters to null CSF signal. This allows standard 3T scanners to achieve sensitivity comparable to 7T scanners for detecting cortical lesions, particularly subpial lesions, without requiring ultra-high field equipment.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If T2*-weighted imaging is used at 7T, then sensitivity to cortical lesions is improved, but signal-to-noise ratio at lower fields deteriorates

Engineering Contradiction:
Improvesensitivity to cortical lesionsVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts and suppresses the CSF signal component from the MRI image using inversion recovery techniques. By nulling the CSF signal, the patent removes the dominant signal source that obscures cortical lesions, thereby improving the visibility and detection of lesions without requiring the high signal-to-noise ratio provided by 7T scanners.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent optimizes T2*-weighted imaging parameters at 3T including setting specific echo times to maximize T2* contrast, using inversion recovery with CSF-nulling parameters, and adjusting acquisition parameters to enhance lesion contrast. These parameter changes compensate for the lower intrinsic signal-to-noise ratio at 3T compared to 7T.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If CSF signal is suppressed, then visibility of cortical lesions is improved, but false positive rates increase

Engineering Contradiction:
Improvevisibility of cortical lesionsVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses T2-preparation pulses as an intermediary mechanism to selectively suppress CSF signal while preserving cortical tissue signal. The T2-prep pulses with specific duration and timing act as a mediator that differentiates between CSF and cortical tissue based on their different T2 relaxation properties, achieving CSF nulling without excessively suppressing cortical signals or creating false positives.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary CSF suppression using inversion recovery and T2-preparation pulses before the actual lesion detection imaging. This preliminary action of nulling the CSF signal beforehand prevents it from obscuring the cortical lesions during the diagnostic imaging phase, improving lesion visibility without requiring post-processing to remove false positives.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If high resolution imaging is performed, then detection of smaller lesions is improved, but scan time increases

Engineering Contradiction:
Improvedetection of smaller lesionsVSAvoidscan time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies local quality enhancement by using T2*-weighted imaging with CSF suppression specifically in the cortical regions where lesions are most likely to occur. Rather than uniformly increasing resolution throughout the entire brain, the methodology focuses contrast enhancement and lesion detectability in the cortical gray matter, allowing efficient detection of subpial and leukocortical lesions without excessive scan time increases.

Inventive Principle:
Principle #3Local quality

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 significantly improves the detection and visualization of cortical lesions, especially subpial lesions, by increasing signal-to-noise ratio and reducing false positives, providing more accurate imaging at 3T field strength comparable to ultra-high field strengths like 7T.

Implementation Method 1

A T2*-weighted MRI sequence with CSF suppression using a 3D-T2*-weighted multi-shot acquisition and T2-prepared inversion pulse

Methodology Applied
Scientific EffectInversion recovery:

Implementation Method 2

T2*-weighted magnetic resonance imaging of cortical lesions

Methodology Applied
Scientific EffectT2* weighting:

Data Source

PatentEP3942318B1High-resolution cerebrospinal fluid-suppressed t2*-weighted magnetic resonance imaging of cortical lesions
Publication Date: 2024.11.13 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES
  • EP3942318B1 patent drawingFigure 1
  • EP3942318B1 patent drawingFigure 2A~2B
  • EP3942318B1 patent drawingFigure 3

AI summary

Provided herein are methods and systems for high-resolution, cerebrospinal fluid-suppressed T2*-weighted magnetic resonance imaging of cortical lesions.