Patchwork reconstruction with resolution modeling for digital breast tomosynthesis

Michielsen, Koen; Slambrouck, Katrien Van; Jerebko, Anna K.

doi:10.1118/1.4789591

Cited by 17 publications

(20 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Three reconstruction algorithms were applied: standard Filtered Back Projection (FBP), 10 FBP with Super Resolution and Statistical Artifact Reduction (SRSAR) 11 and multigrid Maximum Likelihood for Transmission with Resolution modeling (MLTR pr ). 12,13 These algorithms may affect performance as they lead to very different image characteristics: the noise and the structures inside the phantom have a different appearance, as illustrated in fig. 2.…”

Section: Image and Phantom Propertiesmentioning

confidence: 98%

Development and application of a channelized Hotelling observer for DBT optimization on structured background test images with mass simulating targets

et al. 2016

Self Cite

View full text Add to dashboard Cite

Digital breast tomosynthesis (DBT) is a 3D mammography technique that promises better visualization of low contrast lesions than conventional 2D mammography. A wide range of parameters influence the diagnostic information in DBT images and a systematic means of DBT system optimization is needed. The gold standard for image quality assessment is to perform a human observer experiment with experienced readers. Using human observers for optimization is time consuming and not feasible for the large parameter space of DBT. Our goal was to develop a model observer (MO) that can predict human reading performance for standard detection tasks of target objects within a structured phantom and subsequently apply it in a first comparative study. The phantom consists of an acrylic semi-cylindrical container with acrylic spheres of different sizes and the remaining space filled with water. Three types of lesions were included: 3D printed spiculated and non-spiculated mass lesions along with calcification groups. The images of the two mass lesion types were reconstructed with 3 different reconstruction methods (FBP, FBP with SRSAR, MLTR pr ) and read by human readers. A Channelized Hotelling model observer was created for the non-spiculated lesion detection task using five Laguerre-Gauss channels, tuned for better performance. For the non-spiculated mass lesions a linear relation between the MO and human observer results was found, with correlation coefficients of 0.956 for standard FBP, 0.998 for FBP with SRSAR and 0.940 for MLTR pr . Both the MO and human observer percentage correct results for the spiculated masses were close to 100%, and showed no difference from each other for every reconstruction algorithm.

show abstract

Section: Image and Phantom Propertiesmentioning

confidence: 98%

Development and application of a channelized Hotelling observer for DBT optimization on structured background test images with mass simulating targets

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…While we are assuming that the focal spot does not vary in the course of data collection for a single image, we found no proof of this in the literature. Given the variability in the shape of the focal spot with amperage and voltage [154] and the little explored variation over long time [196], mechanical movement [183,197] and vibration [98] and other effects requiring physical or algorithmic realignment [198], it would be wise to have a built in, periodic, automatic, digital imaging of the focal spot, its spatial variation, and its position [199] in CT scanners using the FoxelCT algorithm. (Table 3), we have chosen to simulate a gantry of diameter 2r = 870 mm with a fan beam angle of subtending 865 detector pixels.…”

Section: Modeling An X-ray Source With Its Focal Spot Width Divided Imentioning

confidence: 99%

Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Alvare¹,

Gordon²

2017

Radiol Diagn Imaging

View full text Add to dashboard Cite

Purpose: In general, there is a reciprocal relationship between the width and flux from an x-ray focal spot (corresponding to spatial resolution and photon noise), so that large focal spots are eschewed in computed tomography (CT) and projection and CT mammography. We wish to overcome this limitation. The goal of foxel based computed tomography (FoxelCT) is to achieve spatial resolution limited by the detector pixel size rather than the focal spot size, and therefore permit the use of much smaller detector pixels and/or larger focal spots in clinical CT. Methods:Rather than using the standard approach of treating the x-ray source as a point, we digitally represent the focal spot as an emission picture consisting of pixels we call foxels (FOcal spot piXELS). Intersections of foxel rays with reconstruction voxels are approximated using the Wu antialiasing line drawing algorithm. All foxel rays in the x-ray light field impinging on a given detector pixel are, in effect, lumped together into a single "passage" or compound ray sum. In this introductory paper noise and other effects that degrade CT are not considered allowing us to demonstrate the upper bound of improvement afforded by the geometry of foxels. The FoxelCT algorithm is a generalization of MART (Multiplicative ART). Results:We show, by simulating a fan beam body scanner configuration, that the loss in resolution versus focal spot size is much slower using foxels compared to the loss when representing the focal spot as a point source. For any given focal spot size, approximating it as a point is always worse than using foxels and furthermore introduces anatomical distortions.Conclusions: Foxels permit the use of larger focal spots and thus greater x-ray photon flux with little loss of resolution. Future scanners could take advantage of foxels to increase the ratio of focal spot size to detector pixel size, via bigger focal spots and/or smaller detector pixels. Existing scanners could be immediately enhanced in image quality via incorporation of foxels in their software. Foxels are applicable to any form of radiological imaging that uses focal spots of finite width, including multisource scanners.

show abstract

“…While the continuous‐motion mode can potentially reduce the total scan time and the motion blur, it may cause additional source blur along the direction of the source motion. This effect has been found to be an image‐quality degrading factor in several studies . A pure step‐and‐shoot mode can alleviate this problem.…”

Section: Introductionmentioning

confidence: 99%

Effect of source blur on digital breast tomosynthesis reconstruction

2019

View full text Add to dashboard Cite

Purpose Most digital breast tomosynthesis (DBT) reconstruction methods neglect the blurring of the projection views caused by the finite size or motion of the x‐ray focal spot. This paper studies the effect of source blur on the spatial resolution of reconstructed DBT using analytical calculation and simulation, and compares the influence of source blur over a range of blurred source sizes. Methods Mathematically derived formulas describe the point spread function (PSF) of source blur on the detector plane as a function of the spatial locations of the finite‐sized source and the object. By using the available technical parameters of some clinical DBT systems, we estimated the effective source sizes over a range of exposure time and DBT scan geometries. We used the CatSim simulation tool (GE Global Research, NY) to generate digital phantoms containing line pairs and beads at different locations and imaged with sources of four different sizes covering the range of potential source blur. By analyzing the relative contrasts of the test objects in the reconstructed images, we studied the effect of the source blur on the spatial resolution of DBT. Furthermore, we simulated a detector that rotated in synchrony with the source about the rotation center and calculated the spatial distribution of the blurring distance in the imaged volume to estimate its influence on source blur. Results Calculations demonstrate that the PSF is highly shift‐variant, making it challenging to accurately implement during reconstruction. The results of the simulated phantoms demonstrated that a typical finite‐sized focal spot (~0.3 mm) will not affect the reconstructed image resolution if the x‐ray tube is stationary during data acquisition. If the x‐ray tube moves during exposure, the extra blur due to the source motion may degrade image resolution, depending on the effective size of the source along the direction of the motion. A detector that rotates in synchrony with the source does not reduce the influence of source blur substantially. Conclusions This study demonstrates that the extra source blur due to the motion of the x‐ray tube during image acquisition substantially degrades the reconstructed image resolution. This effect cannot be alleviated by rotating the detector in synchrony with the source. The simulation results suggest that there are potential benefits of modeling the source blur in image reconstruction for DBT systems using continuous‐motion acquisition mode.

show abstract

Patchwork reconstruction with resolution modeling for digital breast tomosynthesis

Cited by 17 publications

References 45 publications

Development and application of a channelized Hotelling observer for DBT optimization on structured background test images with mass simulating targets

Development and application of a channelized Hotelling observer for DBT optimization on structured background test images with mass simulating targets

Foxels for high flux, high resolution computed tomography (foxelct) Using broad x-ray focal spots

Effect of source blur on digital breast tomosynthesis reconstruction

Contact Info

Product

Resources

About