Evaluation of parallel and fan-beam data acquisition geometries and strategies for myocardial SPECT imaging

Qi, Yu; Tsui, B.M.W.; Gilland, K.L.; Frey, Eric; Gullberg, Grant T.

doi:10.1109/tns.2004.829737

Cited by 7 publications

(2 citation statements)

References 9 publications

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“…A 256 × 256 projection matrix with 0.156 cm bins was used for each view. After the 256 × 256 noise-free projection data were collapsed to 128 × 128, they were scaled to the total count of 200 000 in an image slice 0.31 cm thickness through the center of the heart (Qi et al 2004). Then the 95 Poisson noise realizations of a single noise-free normal heart and 95 noise realizations of a single noise-free myocardium with the motion defect were generated.…”

Section: Generation Of Realistic 4d Ncat Phantom and Projection Datamentioning

confidence: 99%

Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

et al. 2015

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We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion abnormality. We concluded that the NMSE-NSDav trade-off was shown to agree with observer performance for the detection task of the regional motion abnormality, and the optimized 4D MAP-RBI-EM method with ADS corrections provides significant improvement compared to 3D FBP and 3D OS-EM with ADS corrections in detecting regional myocardial wall motion abnormali in 4D gated MP SPECT.

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Section: Generation Of Realistic 4d Ncat Phantom and Projection Datamentioning

confidence: 99%

Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

et al. 2015

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“…The count level of the projection data was determined based on a previous study (Lee and Tsui 2010) in which we performed an evaluation study of a corrective image reconstruction method for various count levels, compared to the conventional FBP method for the same detectability of myocardial perfusion defect. Since the model observer is generally more efficient than the human observer, defect detection in the reconstructed images was too easy at the clinically realistic 99m Tc-sestamibi count level of 200 000 total counts in a 0.31 cm thick image slice through the center of the heart (Qi et al 2004). Based on these studies, the acquired counts level was set to 20% of a typical clinical count level to give AUC values around 0.8 where minimum noise and maximum statistical power can be achieved in the ROC analysis.…”

Section: Simulation Of Myocardial Perfusion Spect Imaging Studymentioning

confidence: 99%

Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT

Lee

Frey²,

Tsui³

2015

Phys. Med. Biol.

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This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical observer model extends the conventional channelized Hotelling observer (CHO) based on a set of 2D spatial channels and the second is a proposed model that uses a set of 4D space-time channels. Simulated projection data were generated using the 4D NURBS-based cardiac-torso (NCAT) phantom with 16 gates/cardiac cycle. The activity distribution modelled uptake of (99m)Tc MIBI with normal perfusion and a regional wall motion defect. An analytical projector was used in the simulation and the filtered backprojection (FBP) algorithm was used in image reconstruction followed by spatial and temporal low-pass filtering with various cut-off frequencies. Then, we extracted 2D image slices from each time frame and reorganized them into a set of cine images. For the first model, we applied 2D spatial channels to the cine images and generated a set of feature vectors that were stacked for the images from different slices of the heart. The process was repeated for each of the 1,024 noise realizations, and CHO and receiver operating characteristics (ROC) analysis methodologies were applied to the ensemble of the feature vectors to compute areas under the ROC curves (AUCs). For the second model, a set of 4D space-time channels was developed and applied to the sets of cine images to produce space-time feature vectors to which the CHO methodology was applied. The AUC values of the second model showed better agreement (Spearman's rank correlation (SRC) coefficient = 0.8) to human observer results than those from the first model (SRC coefficient = 0.4). The agreement with human observers indicates the proposed 4D mathematical observer model provides a good predictor of the performance of human observers in detecting regional motion defects in 4D gated MP SPECT images. The result supports the use of the observer model in the optimization and evaluation of 4D image reconstruction and compensation methods for improving the detection of motion abnormalities in 4D gated MP SPECT images.

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Predicting human performance by channelized Hotelling observer in discriminating between Alzheimer’s dementia and controls using statistically processed brain perfusion SPECT

et al. 2006

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Evaluation of parallel and fan-beam data acquisition geometries and strategies for myocardial SPECT imaging

Cited by 7 publications

References 9 publications

Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT

Predicting human performance by channelized Hotelling observer in discriminating between Alzheimer’s dementia and controls using statistically processed brain perfusion SPECT

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