Convergence optimization of parametric MLEM reconstruction for estimation of Patlak plot parameters
Georgios I Angelis1, Kris Thielemans, Andri C Tziortzi
1MRC Clinical Sciences Centre, Imperial College London, Cyclotron Building, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK. georgios.angelis@mmic.man.ac.uk
Summary
This study presents a direct parametric reconstruction algorithm for dynamic positron emission tomography (PET) imaging using [(18)F]DOPA. The method offers robust and reproducible quantitative results for parametric imaging, improving upon traditional approaches.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Computational Science
Background:
- Dynamic positron emission tomography (PET) imaging often relies on kinetic modeling for quantitative analysis.
- Estimating parametric images directly during reconstruction is an active area of research.
Purpose of the Study:
- To investigate a direct parametric maximum likelihood expectation maximization (MLEM) algorithm for dynamic PET reconstruction.
- To evaluate the algorithm's performance using [(18)F]DOPA data with a reference-tissue input function.
Main Methods:
- A modified direct parametric MLEM algorithm was employed with a gradually descending subset scheme (18-6-1).
- The algorithm was initialized with filtered back-projection (FBP) parametric images for enhanced convergence and accuracy.
- The study utilized dynamic [(18)F]DOPA PET data from six human acquisitions.
Main Results:
- Direct reconstruction demonstrated quantitative robustness with minimal bias when compared to analytic reconstructions.
- Clinical reproducibility was achieved within the region of interest across multiple human studies.
- Bland-Altman analysis confirmed good quantitative agreement between direct reconstructed parametric maps and indirect FBP methods.
Conclusions:
- The direct parametric MLEM algorithm provides a robust and reproducible method for quantitative kinetic modeling in dynamic PET.
- This approach offers potential for improved accuracy and efficiency in analyzing [(18)F]DOPA PET data.
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