Modeling blurring effects due to continuous gantry rotation: Application to region of interest tomography

Cant, Jeroen; Palenstijn, Willem Jan; Behiels, Gert; Sijbers, Jan

doi:10.1118/1.4914422

Cited by 10 publications

(5 citation statements)

References 26 publications

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“…The simulation study involved a step-andshoot model (see, continuous rotation in the actual CBCT-A system), thus ignoring the effects of azimuthal blur that may arise from integration over the rotation angular extent of the (albeit brief) x-ray pulse. This effect and corresponding correction approaches (Yang et al 2007, Cant et al 2015 could be taken into account in future studies, but is believed to have small influence on the observations in this work due to the short pulse lengths (<10 ms).…”

Section: Discussionmentioning

confidence: 97%

Reconstruction-of-difference (RoD) imaging for cone-beam CT neuro-angiography

Stayman

Mow

et al. 2018

Phys. Med. Biol.

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Timely evaluation of neurovasculature via CT angiography (CTA) is critical to the detection of pathology such as ischemic stroke. Cone-beam CTA (CBCT-A) systems provide potential advantages in the timely use at the point-of-care, although challenges of a relatively slow gantry rotation speed introduce tradeoffs among image quality, data consistency and data sparsity. This work describes and evaluates a new reconstruction-of-difference (RoD) approach that is robust to such challenges. A fast digital simulation framework was developed to test the performance of the RoD over standard reference reconstruction methods such as filtered back-projection (FBP) and penalized likelihood (PL) over a broad range of imaging conditions, grouped into three scenarios to test the trade-off between data consistency, data sparsity and peak contrast. Two experiments were also conducted using a CBCT prototype and an anthropomorphic neurovascular phantom to test the simulation findings in real data. Performance was evaluated primarily in terms of normalized root mean square error (NRMSE) in comparison to truth, with reconstruction parameters chosen to optimize performance in each case to ensure fair comparison. The RoD approach reduced NRMSE in reconstructed images by up to 50%-53% compared to FBP and up to 29%-31% compared to PL for each scenario. Scan protocols well suited to the RoD approach were identified that balance tradeoffs among data consistency, sparsity and peak contrast-for example, a CBCT-A scan with 128 projections acquired in 8.5 s over a 180° + fan angle half-scan for a time attenuation curve with ~8.5 s time-to-peak and 600 HU peak contrast. With imaging conditions such as the simulation scenarios of fixed data sparsity (i.e. varying levels of data consistency and peak contrast), the experiments confirmed the reduction of NRMSE by 34% and 17% compared to FBP and PL, respectively. The RoD approach demonstrated superior performance in 3D angiography compared to FBP and PL in all simulation and physical experiments, suggesting the possibility of CBCT-A on low-cost, mobile imaging platforms suitable to the point-of-care. The algorithm demonstrated accurate reconstruction with a high degree of robustness against data sparsity and inconsistency.

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Section: Discussionmentioning

confidence: 97%

Reconstruction-of-difference (RoD) imaging for cone-beam CT neuro-angiography

Stayman

Mow

et al. 2018

Phys. Med. Biol.

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“…The X-ray source and flat-panel detector rotate simultaneously, and projection data in step-and-shoot mode were generated from 25 views within a limited angular range of ±25° ( Fig 1(a) ). For the projection data in continuous mode, the angular span of each view was divided into 11 sub-angular samples (i.e., 11 view-lets) [ 20 ]. Afterward, the projection data of all view-let samples were averaged as shown in Fig 1(b) .…”

Section: Methodsmentioning

confidence: 99%

Effect of optical blurring of X-ray source on breast tomosynthesis image quality: Modulation transfer function, anatomical noise power spectrum, and signal detectability perspectives

Lee

Baek

2022

PLoS ONE

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We investigated the effect of the optical blurring of X-ray source on digital breast tomosynthesis (DBT) image quality using well-designed DBT simulator and table-top experimental systems. To measure the in-plane modulation transfer function (MTF), we used simulated sphere phantom and Teflon sphere phantom and generated their projection data using two acquisition modes (i.e., step-and-shoot mode and continuous mode). After reconstruction, we measured the in-plane MTF using reconstructed sphere phantom images. In addition, we measured the anatomical noise power spectrum (aNPS) and signal detectability. We constructed simulated breast phantoms with a 50% volume glandular fraction (VGF) of breast anatomy using the power law spectrum and inserted spherical objects with 1 mm, 2 mm, and 5 mm diameters as breast masses. Projection data were acquired using two acquisition modes, and in-plane breast images were reconstructed using the Feldkamp-Davis-Kress (FDK) algorithm. For the experimental study, we used BR3D breast phantom with 50% VGF and obtained projection data using a table-top experimental system. To compare the detection performance of the two acquisition modes, we calculated the signal detectability using the channelized Hotelling observer (CHO) with Laguerre-Gauss (LG) channels. Our results show that spatial resolution of in-plane image in continuous mode was degraded due to the optical blurring of X-ray source. This blurring effect was reflected in aNPS, resulting in large β values. From a signal detectability perspective, the signal detectability in step-and-shoot mode is higher than that in continuous mode for small spherical signals but not large spherical signals. Although the step-and-shoot mode has disadvantage in terms of scan time compared to the continuous mode, scanning in step-and-shoot mode is better for detecting small signals, indicating that there is a tradeoff between scan time and image quality.

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“…However, the continuous motion during capturing a radiograph is associated with a loss of resolution. Any significant movement of the sample during an exposure will lead to a loss of the higher spatial frequencies of a radiograph [22]. The amount of resolution lost when scanning with continuous motion depends on the projected pixel size and the magnitude of the rotation during the generation of the radiograph.…”

Section: Introductionmentioning

confidence: 99%

Increasing throughput in x-ray computed tomography measurement of surface topography using sinogram interpolation

Körner

Lawes

Bate

et al. 2019

Meas. Sci. Technol.

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X-ray computed tomography (XCT) is a non-destructive imaging technique that has recently gained interest as a tool to measure surface topography. Large acquisition times are a major shortcoming of XCT. One contributing factor to the acquisition time is that a measurement can require the acquisition of thousands of radiographic projections. This paper explores the combined effects of undersampling, i.e. taking fewer radiographic projections and sinogram interpolation, i.e. estimating the missing radiographic projections by interpolation. Different degrees of sinogram interpolation are investigated through the measurement of the surfaces of a metal, additively manufactured part. The quality of the measurement result is assessed via the analysis of the reconstructed volumes, through the computation of quantitative indicators of spatial resolution and noise, and via the analysis of surface topographies extracted from the reconstructed volumes. The quality of the surfaces is assessed through the use of statistical models designed to estimate repeatability errors in the reconstruction, and through the computation of surface texture parameters. Results obtained with no undersampling and no sinogram interpolation are taken as reference. It is shown that noise in the volumetric reconstruction increases with respect to the reference with larger degrees of undersampling, but the increment can be partly compensated by sinogram interpolation with the effects on spatial resolution more difficult to interpret. The computation of surface texture parameters results in similar values for all but one case, the largest undersampling. The topography of the reconstructions indicate that the repeatability error remains similar in all experimental conditions, excluding the case of largest undersampling. Overall, the results indicate that a reduction of the acquisition time of XCT topography measurement is feasible. However, the obtained surface topographies suffer, and large undersampling creates unrecoverable negative effects on the spatial resolution, the noise characteristics and the obtained topographies, even when sinogram interpolation is used.

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Modeling blurring effects due to continuous gantry rotation: Application to region of interest tomography

Cited by 10 publications

References 26 publications

Reconstruction-of-difference (RoD) imaging for cone-beam CT neuro-angiography

Reconstruction-of-difference (RoD) imaging for cone-beam CT neuro-angiography

Effect of optical blurring of X-ray source on breast tomosynthesis image quality: Modulation transfer function, anatomical noise power spectrum, and signal detectability perspectives

Increasing throughput in x-ray computed tomography measurement of surface topography using sinogram interpolation

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