CEST MRI Cardiac pH Gating Synchronization

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Solution Overview

Problem

Current cardiac pH analysis techniques using phosphorus (31P) MR spectroscopy face challenges with coarse spatiotemporal resolution, limiting their routine clinical application for diagnosing myocardial infarction and ischemia.

Innovation Solution

The method involves acquiring and analyzing physiological monitoring signals to identify trigger points, applying RF saturation, and performing chemical exchange saturation transfer (CEST) readouts to produce CEST images, which provide sensitive metabolic information about cardiac pH levels without invasive procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phosphorus (31P) MR spectroscopy is used for cardiac pH analysis, then metabolic information can be obtained, but the spatiotemporal resolution is coarse

Engineering Contradiction:

Improvespatiotemporal resolutionVSAvoidtechnical complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses CEST MRI as an intermediary technique to indirectly measure cardiac pH. Instead of directly detecting phosphorus metabolites with 31P spectroscopy, the method saturates amide protons of intracellular proteins and detects the transferred saturation to water protons, providing pH information with superior spatial and temporal resolution while avoiding the technical limitations of direct phosphorus spectroscopy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameter from direct phosphorus metabolite detection to indirect water signal modulation via chemical exchange. By monitoring the saturation transfer from amide protons to water protons, the system achieves pH measurement with enhanced spatiotemporal resolution, transforming the measurement approach from direct low-resolution spectroscopy to indirect high-resolution imaging

Inventive Principle:

Principle #35Parameter changes

2Productivity

If RF saturation and CEST readout are applied without gating, then acquisition speed increases, but motion artifacts increase

Engineering Contradiction:

Improveacquisition speedVSAvoidimage quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements periodic gating of the RF saturation and CEST readout sequences synchronized to the cardiac cycle. By periodically activating the saturation pulses and readouts at specific phases of the cardiac cycle (e.g., during diastole), the method maintains consistent anatomical positioning across multiple acquisitions, reducing motion artifacts while preserving acceptable acquisition speed through efficient use of the cardiac cycle

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent uses physiological monitoring signals (such as ECG) as feedback to trigger and synchronize the RF saturation and CEST readout sequences. The system continuously monitors the cardiac cycle phase and adjusts the timing of saturation pulses and acquisitions accordingly, ensuring that imaging occurs at optimal moments in the cardiac cycle when motion is minimized, thereby reducing artifacts while maintaining productivity

Inventive Principle:

Principle #23Feedback

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 enhances the sensitivity and specificity of cardiac pH analysis, reducing motion artifacts and improving image quality, enabling non-invasive, clinically useful metabolic imaging for diagnosing myocardial infarction and ischemia.

Implementation Method 1

magnetic field gradients (Gx, Gy, and Gz) are employed

Methodology Applied

Scientific EffectMagnetic field gradients: Magnetic Field

Implementation Method 2

precess about it in random order at their characteristic Larmor frequency

Methodology Applied

Scientific EffectLarmor precession: Precession

Implementation Method 3

the region to be imaged is scanned by a sequence of measurement cycles in which these gradients vary according to the particular localization method being used

Methodology Applied

Scientific EffectRF excitation: Electromagnetic Induction

Implementation Method 4

A signal is emitted by the excited nuclei or 'spins,' after the excitation signal B1 is terminated

Methodology Applied

Scientific EffectMagnetic resonance signal emission: Electromagnetic Induction

Data Source

PatentUS11428768B2Chemical exchange saturation transfer magnetic resonance imaging with gating synchronized acquisition

Publication Date: 2022.08.30 THE GENERAL HOSPITAL CORP

AI summary

Methods and systems for producing a magnetic resonance (MR) image of a subject include acquiring a first physiological monitoring signal related to a first physiological process of the subject and acquiring a second physiological monitoring signal related to a second physiological process of the subject. The method also includes analyzing the first physiological monitoring signal and the second physiological monitoring signal to identify at least a first trigger point and a second trigger point and, upon identifying the first trigger point, applying a radiofrequency (RF) saturation module at a selected frequency to saturate a selected spin species in the subject. Upon identifying the second trigger point, the method includes performing a chemical exchange striation transfer (CEST) readout to acquire CEST data and then reconstructing the CEST data to produce a CEST image of the subject.