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Author Spotlight: Enhancing Diagnostic Strategies and Biomarker Development for Comprehensive Lung Function Analysis
Published on: August 9, 2024
PET/MRI attenuation estimation in the lung: A review of past, present, and potential techniques
Joseph Lillington1, Ludovica Brusaferri2, Kerstin Kläser3
1Centre for Medical Imaging, University College London, London, W1W 7TS, UK.
Abstract:
Positron emission tomography/magnetic resonance imaging (PET/MRI) potentially offers several advantages over positron emission tomography/computed tomography (PET/CT), for example, no CT radiation dose and soft tissue images from MR acquired at the same time as the PET. However, obtaining accurate linear attenuation correction (LAC) factors for the lung remains difficult in PET/MRI. LACs depend on electron density and in the lung, these vary significantly both within an individual and from person to person. Current commercial practice is to use a single-valued population-based lung LAC, and better estimation is needed to improve quantification. Given the under-appreciation of lung attenuation estimation as an issue, the inaccuracy of PET quantification due to the use of single-valued lung LACs, the unique challenges of lung estimation, and the emerging status of PET/MRI scanners in lung disease, a review is timely. This paper highlights past and present methods, categorizing them into segmentation, atlas/mapping, and emission-based schemes. Potential strategies for future developments are also presented.
Insights
Accurate lung attenuation correction in positron emission tomography/magnetic resonance imaging (PET/MRI) is crucial for precise quantification. This review examines current and future methods to improve lung attenuation estimation in PET/MRI scans.
Area of Science:
- Medical Imaging Physics
- Radiological Sciences
- Nuclear Medicine
Background:
- Positron emission tomography/magnetic resonance imaging (PET/MRI) offers advantages over PET/CT, including no CT radiation dose and simultaneous soft-tissue MR imaging.
- Accurate linear attenuation correction (LAC) for lung tissue in PET/MRI is challenging due to significant variations in electron density.
- Current clinical practice relies on population-based lung LACs, potentially leading to inaccurate PET quantification.
Purpose of the Study:
- To review existing and emerging methods for estimating lung linear attenuation correction (LAC) factors in positron emission tomography/magnetic resonance imaging (PET/MRI).
- To highlight the challenges and importance of accurate lung attenuation estimation for quantitative PET imaging.
- To discuss future strategies for improving lung attenuation correction in PET/MRI, particularly for lung disease applications.
Main Methods:
- Categorization of current and past lung attenuation estimation methods into segmentation-based, atlas/mapping-based, and emission-based schemes.
- Review of techniques addressing the variability of electron density within lung tissues.
- Discussion of potential future developments and strategies for enhanced accuracy.
Main Results:
- Existing methods for lung attenuation correction in PET/MRI vary in complexity and accuracy.
- Significant challenges remain in achieving precise, individualized lung LACs due to inherent tissue heterogeneity.
- The review synthesizes various approaches, identifying strengths and limitations of each category.
Conclusions:
- Accurate lung attenuation correction is critical for reliable quantitative PET imaging with PET/MRI, especially in lung disease.
- Further research and development are needed to overcome the challenges of lung attenuation estimation.
- The reviewed methods provide a foundation for developing improved strategies for future PET/MRI applications.
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