MRI Signal Decay Variance Map for Disc Degeneration
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Solution Overview
Problem
Diagnosing tissue degeneration, such as intervertebral disc degeneration, using MRI images is challenging due to the poor correlation of qualitative schemes with pain and the limited clinical use of quantitative techniques.
Innovation Solution
A method employing a computer system to determine signal decay variance for MRI images, generating an MRI signal decay variance map, and creating a tissue degeneration indicator to assess the extent of tissue degeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If qualitative schemes are used for diagnosing tissue degeneration using MRI images, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent transforms qualitative MRI assessment into quantitative measurement by calculating signal decay variance (SDV) from multi-echo T2-weighted MRI sequences. The SDV metric is derived through mathematical processing of signal intensities across multiple echo times, converting subjective visual evaluation into an objective numerical value that correlates with histological grading of disc degeneration.
2Measurement precision
If traditional quantitative techniques like T2 relaxometry are used, then measurement precision is improved, but device complexity and computational intensity increase
Solution Approach 1:
The patent extracts the essential diagnostic information by focusing specifically on signal decay variance rather than performing complete T2 relaxometry analysis. Instead of calculating full T2 relaxation curves and maps which require complex fitting algorithms, the method extracts the variance component from multi-echo signals, achieving comparable or superior diagnostic accuracy with reduced computational burden.
Solution Approach 2:
The method uses a partial quantitative approach by calculating only the signal decay variance metric from multi-echo sequences rather than performing complete quantitative T2 mapping. This partial action provides sufficient diagnostic information for disc degeneration assessment while avoiding the excessive computational requirements of full quantitative analysis.
3Measurement precision
If traditional quantitative techniques like T2 relaxometry are used, then measurement precision is improved, but productivity deteriorates due to computational intensity
Solution Approach 1:
The patent replaces the computationally intensive mechanical process of T2 curve fitting and relaxation map generation with a simpler mathematical calculation of signal decay variance. This substitution maintains measurement precision while dramatically reducing processing time and computational resources required, thereby improving clinical productivity.
Data Source
AI summary
In some embodiments, spinal disc degeneracy is diagnosed according to a decay variance map generated by determining a variance in T2 decay over time within each pixel or pixel subset of an MRI image. A region of interest may be defined as including nucleus pulposus (NP) and annulus fibrosus (AF) areas, and excluding cartilaginous endplate (EP) areas of a disc. A decay variance for a pixel or groups of pixels is calculated by determining ratios between consecutive intensity values of the T2 signal, determining differences between consecutive ratios, and summing the absolute values of the determined differences. Decay variance mapping may be used to diagnose degeneracy in other tissues, such as in joints.