Effect of non-isotropic detector blur on microcalcification detectability in tomosynthesis

Reiser, Ingrid; Nishikawa, Robert M.; Lau, Beverly

doi:10.1117/12.813808

Cited by 4 publications

(6 citation statements)

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“…In addition, the total scan time affects motion artifacts and generally increases with both the total angle scanned and the number of projection views. Researchers have also found that increased angular range can result in a decrease in planar spatial resolution for both direct and indirect detectors (Acciavatti and Maidment, 2010, 2011; Badano et al , 2011; Badano et al , 2007; Freed et al , 2010; Mainprize et al , 2006; Reiser et al , 2009; Zhao and Zhao, 2008). On the other hand, undersampling artifacts may arise when too few projections are acquired (Maidment et al , 2006; Reiser et al , 2009).…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the image noise tends to increase with increased incidence angle because of the longer pathlength of x-ray attenuation in the breast phantom. Greater incidence angles to the detector also reduce planar spatial resolution for both direct and indirect detectors (Acciavatti and Maidment, 2010, 2011; Badano et al , 2011; Badano et al , 2007; Freed et al , 2010; Mainprize et al , 2006; Reiser et al , 2009; Zhao and Zhao, 2008). All of these factors counter the advantage of reduced effective slice thickness with increased tomosynthesis angle.…”

Section: Discussionmentioning

confidence: 99%

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Digital breast tomosynthesis: studies of the effects of acquisition geometry on contrast-to-noise ratio and observer preference of low-contrast objects in breast phantom images

et al. 2014

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The effect of acquisition geometry in digital breast tomosynthesis (DBT) was evaluated with studies of contrast-to-noise ratios (CNRs) and observer preference. Contrast-detail (CD) test objects in 5 cm thick phantoms with breast-like backgrounds were imaged. Twelve different angular acquisitions (average glandular dose for each ~1.1 mGy) were performed ranging from narrow angle 16° with 17 projection views (16d17p) to wide angle 64d17p. Focal slices of SART-reconstructed images of the CD arrays were selected for CNR computations and the reader preference study. For the latter, pairs of images obtained with different acquisition geometries were randomized and scored by 7 trained readers. The total scores for all images and readings for each acquisition geometry were compared as were the CNRs. In general, readers preferred images acquired with wide angle as opposed to narrow angle geometries. The mean percent preferred was highly correlated with tomosynthesis angle (R=0.91). The highest scoring geometries were 60d21p (95%), 64d17p (80%), and 48d17p (72%); the lowest scoring were 16d17p (4%), 24d9p (17%) and 24d13p (33%). The measured CNRs for the various acquisitions showed much overlap but were overall highest for wide-angle acquisitions. Finally, the mean reader scores were well correlated with the mean CNRs (R=0.83).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Digital breast tomosynthesis: studies of the effects of acquisition geometry on contrast-to-noise ratio and observer preference of low-contrast objects in breast phantom images

et al. 2014

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“…48 We anticipate that this will mostly affect small- scale signals. We will also include the effects of detector noise that will likely affect the results for different number of views.…”

Section: Discussionmentioning

confidence: 99%

Task-based assessment of breast tomosynthesis: Effect of acquisition parameters and quantum noisea)

2010

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Purpose: Tomosynthesis is a promising modality for breast imaging. The appearance of the tomosynthesis reconstructed image is greatly affected by the choice of acquisition and reconstruction parameters. The purpose of this study was to investigate the limitations of tomosynthesis breast imaging due to scan parameters and quantum noise. Tomosynthesis image quality was assessed based on performance of a mathematical observer model in a signal-known exactly ͑SKE͒ detection task. Methods: SKE detectability ͑dЈ͒ was estimated using a prewhitening observer model. Structured breast background was simulated using filtered noise. Detectability was estimated for designer nodules ranging from 0.05 to 0.8 cm in diameter. Tomosynthesis slices were reconstructed using iterative maximum-likelihood expectation-maximization. The tomosynthesis scan angle was varied between 15°and 60°, the number of views between 11 and 41 and the total number of x-ray quanta was ϱ, 6ϫ 10 5 , and 6 ϫ 10 4 . Detectability in tomosynthesis was compared to that in a single projection. Results: For constant angular sampling distance, increasing the angular scan range increased detectability for all signal sizes. Large-scale signals were little affected by quantum noise or angular sampling. For small-scale signals, quantum noise and insufficient angular sampling degraded detectability. At high quantum noise levels, angular step size of 3°or below was sufficient to avoid image degradation. At lower quantum noise levels, increased angular sampling always resulted in increased detectability. The ratio of detectability in the tomosynthesis slice to that in a single projection exhibited a peak that shifted to larger signal sizes when the angular range increased. For a given angular range, the peak shifted toward smaller signals when the number of views was increased. The ratio was greater than unity for all conditions evaluated. Conclusion: The effect of acquisition parameters on lesion detectability depends on signal size. Tomosynthesis scan angle had an effect on detectability for all signals sizes, while quantum noise and angular sampling only affected the detectability small-scale signals.

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“…In future work, we can improve the detector model by incorporating energy-, depth-, and angle-dependent information. [59][60][61][62] As the simulations grow faster and more efficient, it should also become practical to investigate polyenergetic source models and scatter models that incorporate the effects of nonuniform phantoms. More realistic physics models combined with computationally efficient model observers can lead to faster and more accurate assessment of image quality in DBT.…”

Section: Discussionmentioning

confidence: 99%

A virtual trial framework for quantifying the detectability of masses in breast tomosynthesis projection data

et al. 2013

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Purpose: Digital breast tomosynthesis (DBT) is a promising breast cancer screening tool that has already begun making inroads into clinical practice. However, there is ongoing debate over how to quantitatively evaluate and optimize these systems, because different definitions of image quality can lead to different optimal design strategies. Powerful and accurate tools are desired to extend our understanding of DBT system optimization and validate published design principles. Methods: The authors developed a virtual trial framework for task-specific DBT assessment that uses digital phantoms, open-source x-ray transport codes, and a projection-space, spatial-domain observer model for quantitative system evaluation. The authors considered evaluation of reconstruction algorithms as a separate problem and focused on the information content in the raw, unfiltered projection images. Specifically, the authors investigated the effects of scan angle and number of angular projections on detectability of a small (3 mm diameter) signal embedded in randomly-varying anatomical backgrounds. Detectability was measured by the area under the receiver-operating characteristic curve (AUC). Experiments were repeated for three test cases where the detectability-limiting factor was anatomical variability, quantum noise, or electronic noise. The authors also juxtaposed the virtual trial framework with other published studies to illustrate its advantages and disadvantages. Results: The large number of variables in a virtual DBT study make it difficult to directly compare different authors' results, so each result must be interpreted within the context of the specific virtual trial framework. The following results apply to 25% density phantoms with 5.15 cm compressed thickness and 500 μm 3 voxels (larger 500 μm 2 detector pixels were used to avoid voxel-edge artifacts): 1. For raw, unfiltered projection images in the anatomical-variability-limited regime, AUC appeared to remain constant or increase slightly with scan angle. 2. In the same regime, when the authors fixed the scan angle, AUC increased asymptotically with the number of projections. The threshold number of projections for asymptotic AUC performance depended on the scan angle. In the quantum-and electronic-noise dominant regimes, AUC behaviors as a function of scan angle and number of projections sometimes differed from the anatomy-limited regime. For example, with a fixed scan angle, AUC generally decreased with the number of projections in the electronic-noise dominant regime. These results are intended to demonstrate the capabilities of the virtual trial framework, not to be used as optimization rules for DBT. Conclusions:The authors have demonstrated a novel simulation framework and tools for evaluating DBT systems in an objective, task-specific manner. This framework facilitates further investigation of image quality tradeoffs in DBT.

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Effect of non-isotropic detector blur on microcalcification detectability in tomosynthesis

Cited by 4 publications

References 0 publications

Digital breast tomosynthesis: studies of the effects of acquisition geometry on contrast-to-noise ratio and observer preference of low-contrast objects in breast phantom images

Digital breast tomosynthesis: studies of the effects of acquisition geometry on contrast-to-noise ratio and observer preference of low-contrast objects in breast phantom images

Task-based assessment of breast tomosynthesis: Effect of acquisition parameters and quantum noisea)

A virtual trial framework for quantifying the detectability of masses in breast tomosynthesis projection data

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