Limited-angle effect compensation for respiratory binned cardiac SPECT
Wenyuan Qi1, Yongyi Yang1, Miles N Wernick1
1Medical Imaging Research Center and Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, Illinois 60616.
Medical Physics
|January 10, 2016
Summary
Respiratory motion in cardiac SPECT causes artifacts. New compensation strategies, particularly a model-based approach, significantly reduce these artifacts and improve myocardial accuracy in SPECT imaging.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Image Reconstruction
Background:
- Cardiac single photon emission computed tomography (SPECT) uses respiratory-binning to mitigate motion blur.
- Variations in respiratory patterns cause data count discrepancies within bins and angles, leading to limited-angle artifacts.
Purpose of the Study:
- To investigate reconstruction strategies for compensating limited-angle effects in respiratory-binned SPECT data.
- To reduce image artifacts caused by respiratory motion variability.
Main Methods:
- Evaluated a model-based correction incorporating acquisition time variation.
- Assessed an approximation approach involving data rescaling.
- Investigated the use of smoothing priors in reconstruction.
- Utilized Monte Carlo simulations with 4D NCAT phantom and clinical data for evaluation.
Main Results:
- All compensation methods reduced artifacts compared to no compensation.
- The model-based approach decreased mean-squared-error by up to 40% and improved myocardial accuracy.
- Model-based approach outperformed data rescaling in accuracy, lesion detectability, and LV wall uniformity.
- Smoothing prior reduced noise and artifacts with minimal bias increase but slight resolution loss.
Conclusions:
- Compensating for acquisition time variations effectively reduces limited-angle artifacts in respiratory-binned cardiac SPECT.
- Integrating time variation into the imaging model with a smoothing prior yields the greatest improvement in myocardial accuracy.
