Deep Learning Denoising for Quantitative SPECT Imaging

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Solution Overview

Problem

SPECT imaging faces challenges in accurately distinguishing and removing noise due to its complex non-linear reconstruction processes and various sources of noise, leading to inaccuracies in quantitative measurements.

Innovation Solution

A machine-learning approach using deep learning is employed to identify and reduce noise in SPECT imaging by training a neural network to estimate the noise structure based on specific imaging settings, allowing for the denoising of reconstructed representations and the generation of noise-reduced images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If non-linear reconstruction process is used to reconstruct activity concentration from detected emissions, then the reconstructed representation can be obtained, but noise is converted from expected statistical distribution into other distributions making it difficult to identify and remove

Engineering Contradiction:
Improveactivity concentration measurement accuracyVSAvoidnoise identification and removal difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

A machine-learned model is introduced as an intermediary between the reconstruction process and noise removal. The model takes the reconstructed representation and associated settings as input, predicts the noise structure, and enables targeted noise removal while preserving the signal. This mediator bridges the gap between complex non-linear reconstruction and noise characterization.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The noise structure is predicted in advance using the machine-learned model before the actual noise removal process. By predicting the noise structure based on reconstruction settings and detected emissions, the system prepares noise characterization data that guides subsequent denoising operations, making noise removal more effective.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If various SPECT imaging arrangements and noise sources are considered, then comprehensive noise modeling is attempted, but the complexity of modeling noise increases due to different collimators, isotopes, scan protocols, and reconstruction methods

Engineering Contradiction:
Improvenoise modeling adaptability to different imaging arrangementsVSAvoidnoise modeling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The machine-learned model uses imaging settings (collimator type, isotope, scan protocol, reconstruction parameters) as input parameters to dynamically adjust noise structure prediction. By changing parameters based on the specific imaging arrangement, the model adapts to different scenarios without requiring separate complex models for each configuration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A single machine-learned model is designed to handle multiple SPECT imaging arrangements and noise sources universally. The model takes various input parameters representing different collimators, isotopes, and reconstruction methods, and predicts appropriate noise structures for each case, eliminating the need for multiple specialized noise models.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If deep learning is used to predict noise structure from imaging settings, then noise can be effectively identified and removed, but computational processing requirements increase

Engineering Contradiction:
Improvenoise removal effectivenessVSAvoidcomputational processing power
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The system applies deep learning selectively to predict noise structure rather than processing all image data through the full deep learning pipeline. By using the machine-learned model only for noise characterization based on imaging settings, computational resources are conserved while maintaining effective noise removal capability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11250545B2Deep learning-based denoising in quantitative single photon emission computed tomography
Publication Date: 2022.02.15 SIEMENS MEDICAL SOLUTIONS USA INC
  • US11250545B2 patent drawing
  • US11250545B2 patent drawing
  • US11250545B2 patent drawing

AI summary

For denoising in SPECT, such as qSPECT, machine learning is used to relate settings to noise structure. Given the SPECT imaging arrangement for a patient, the machine-learned model estimates the structure of the noise. This noise structure may be used to denoise the reconstructed representation.