MR-Derived PET Attenuation Correction via Bone Classification

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Solution Overview

Problem

Multi-modality imaging systems, such as PET-CT and PET-MR, face challenges in image quality due to patient motion and inaccurate attenuation correction, leading to artifacts and reduced diagnostic value in PET scans.

Innovation Solution

A method and system that utilize MRI data to classify bones and generate MR-derived PET attenuation correction factors, which are then used to correct PET emission data, improving image quality by accurately accounting for bone density and structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If MR data is utilized to generate a linear attenuation map at 511 keV, then PET attenuation correction can be performed, but unwanted artifacts or inaccurate PET quantitation may result

Engineering Contradiction:

ImprovePET attenuation correction accuracyVSAvoidPET quantitation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary process that uses MR data at its native frequency to generate a frequency-matched attenuation map specifically for 511 keV PET photons. This intermediary transformation ensures that the attenuation correction is tailored to the specific energy requirements of PET imaging, avoiding direct application of MR data which operates at different frequencies and can cause artifacts.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter of frequency/energy representation when generating the attenuation map. Instead of using MR data directly at its acquisition frequency, the system transforms the data to represent attenuation at 511 keV, matching the PET photon energy. This parameter transformation resolves the contradiction by ensuring the attenuation correction is physically accurate for PET imaging.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If CT data is utilized to generate attenuation correction factors, then accurate attenuation correction can be achieved, but additional scanning time and system complexity are required

Engineering Contradiction:

Improveattenuation correction accuracyVSAvoidscanning time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the attenuation correction function into the MR imaging sequence itself, eliminating the need for separate CT scanning. By generating the attenuation map from the MR data that is already being acquired for diagnostic purposes, the system achieves accurate attenuation correction without adding separate scanning time or requiring an additional CT system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the MR imaging system multi-functional by enabling it to serve both diagnostic imaging purposes and attenuation correction for PET. The same MR data acquisition and processing system that produces diagnostic images also generates the attenuation map, eliminating the need for dedicated CT hardware and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8923592B2Methods and systems for performing attenuation correction

Publication Date: 2014.12.30 GE PRECISION HEALTHCARE LLC

AI summary

A method for correcting a positron emission tomography (PET) image includes obtaining a magnetic resonance (MR) image dataset, classifying at least one object in the MR image as a bone, generating MR-derived PET attenuation correction factors based on the object classified as the bone, and attenuation correcting a plurality of positron emission tomography (PET) emission data using the MR-derived PET attenuation correction factors. A medical imaging system and a non-transitory computer readable medium are also described herein.