Ms. Jennifer Xu Profile

Jennifer Xu

PhD Candidate at Johns Hopkins Univ

SPIE Involvement:

Author

Area of Expertise:

Medical Imaging , Image quality metrology , Photon Counting X-Ray detectors

Publications (8)

Proceedings Article | 9 March 2017 Presentation + Paper

Brain perfusion imaging using a Reconstruction-of-Difference (RoD) approach for cone-beam computed tomography

M. Mow, W. Zbijewski, A. Sisniega, J. Xu, H. Dang, J. Stayman, X. Wang, D. Foos, V. Koliatsos, N. Aygun, J. Siewerdsen

Proceedings Volume 10132, 1013212 (2017) https://doi.org/10.1117/12.2255690

KEYWORDS: Neuroimaging, Brain, Imaging systems, Computed tomography, Scanners, Image enhancement, Cones, Head, Brain imaging, Ischemic stroke, Tissues, Signal attenuation

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Proceedings Article | 9 March 2017 Presentation + Paper

Development and clinical translation of a cone-beam CT scanner for high-quality imaging of intracranial hemorrhage

A. Sisniega, J. Xu, H. Dang, W. Zbijewski, J. Stayman, M. Mow, V. Koliatsos, N. Aygun, X. Wang, D. Foos, J. Siewerdsen

Proceedings Volume 10132, 101320K (2017) https://doi.org/10.1117/12.2255670

KEYWORDS: Reconstruction algorithms, Computed tomography, Point spread functions, Scanners, Point-of-care devices, Prototyping, Imaging systems, Model-based design, Image quality, Head, Image resolution, Bone

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Purpose: Prompt, reliable detection of intracranial hemorrhage (ICH) is essential for treatment of stroke and traumatic brain injury, and would benefit from availability of imaging directly at the point-of-care. This work reports the performance evaluation of a clinical prototype of a cone-beam CT (CBCT) system for ICH imaging and introduces novel algorithms for model-based reconstruction with compensation for data truncation and patient motion.

Methods: The tradeoffs in dose and image quality were investigated as a function of analytical (FBP) and model-based iterative reconstruction (PWLS) algorithm parameters using phantoms with ICH-mimicking inserts. Image quality in clinical applications was evaluated in a human cadaver imaged with simulated ICH. Objects outside of the field of view (FOV), such as the head-holder, were found to introduce challenging truncation artifacts in PWLS that were mitigated with a novel multi-resolution reconstruction strategy. Following phantom and cadaver studies, the scanner was translated to a clinical pilot study. Initial clinical experience indicates the presence of motion in some patient scans, and an image-based motion estimation method that does not require fiducial tracking or prior patient information was implemented and evaluated.

Results: The weighted CTDI for a nominal scan technique was 22.8 mGy. The high-resolution FBP reconstruction protocol achieved < 0.9 mm full width at half maximum (FWHM) of the point spread function (PSF). The PWLS soft-tissue reconstruction showed <1.2 mm PSF FWHM and lower noise than FBP at the same resolution. Effects of truncation in PWLS were mitigated with the multi-resolution approach, resulting in 60% reduction in root mean squared error compared to conventional PWLS. Cadaver images showed clear visualization of anatomical landmarks (ventricles and sulci), and ICH was conspicuous. The motion compensation method was shown in clinical studies to restore visibility of fine bone structures, such as the subtle fracture, cranial sutures, and the cochlea as well as subtle low-contrast structures in the brain parenchyma.

Conclusion: The imaging performance of the prototype suggests sufficient quality for ICH imaging and motivates continued clinical studies to assess the diagnosis utility of the CBCT system in realistic clinical scenarios at the point of care.

Proceedings Article | 31 March 2016 Paper

Regularization design for high-quality cone-beam CT of intracranial hemorrhage using statistical reconstruction

H. Dang, J. W. Stayman, J. Xu, A. Sisniega, W. Zbijewski, X. Wang, D. Foos, N. Aygun, V. Koliatsos, J. Siewerdsen

Proceedings Volume 9783, 97832Y (2016) https://doi.org/10.1117/12.2216937

KEYWORDS: Spatial resolution, Computed tomography, Image quality, Statistical modeling, Traumatic brain injury, Blood, Head, Optical spheres, Brain, Modulation transfer functions, Point spread functions

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Proceedings Article | 22 March 2016 Paper

Design and characterization of a dedicated cone-beam CT scanner for detection of acute intracranial hemorrhage

J. Xu, A. Sisniega, W. Zbijewski, H. Dang, J. W. Stayman, X. Wang, D. Foos, N. Aygun, V. Koliatsos, J. Siewerdsen

Proceedings Volume 9783, 97830T (2016) https://doi.org/10.1117/12.2216544

KEYWORDS: Imaging systems, Traumatic brain injury, Prototyping, X-ray computed tomography, Scanners, Computing systems, Image quality, Model-based design, Sensors, Performance modeling

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Proceedings Article | 18 March 2015 Paper

Cone-beam CT of traumatic brain injury using statistical reconstruction with a post-artifact-correction noise model

H. Dang, J. Stayman, A. Sisniega, J. Xu, W. Zbijewski, J. Yorkston, N. Aygun, V. Koliatsos, J. Siewerdsen

Proceedings Volume 9412, 941207 (2015) https://doi.org/10.1117/12.2082075

KEYWORDS: Traumatic brain injury, Spatial resolution, Image quality, Head, Imaging systems, Model-based design, Monte Carlo methods, Statistical modeling, Point-of-care devices, Optical spheres

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Proceedings Article | 18 March 2015 Paper

Spectral CT of the extremities with a silicon strip photon counting detector

A. Sisniega, W. Zbijewski, J. Stayman, J. Xu, K. Taguchi, J. Siewerdsen

Proceedings Volume 9412, 94120Z (2015) https://doi.org/10.1117/12.2082092

KEYWORDS: Sensors, Iodine, Bone, Calibration, X-ray computed tomography, Silicon, Photon counting, Signal attenuation, Tissues, Imaging spectroscopy

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Purpose: Photon counting x-ray detectors (PCXDs) are an important emerging technology for spectral imaging and material differentiation with numerous potential applications in diagnostic imaging. We report development of a Si-strip PCXD system originally developed for mammography with potential application to spectral CT of musculoskeletal extremities, including challenges associated with sparse sampling, spectral calibration, and optimization for higher energy x-ray beams. Methods: A bench-top CT system was developed incorporating a Si-strip PCXD, fixed anode x-ray source, and rotational and translational motions to execute complex acquisition trajectories. Trajectories involving rotation and translation combined with iterative reconstruction were investigated, including single and multiple axial scans and longitudinal helical scans. The system was calibrated to provide accurate spectral separation in dual-energy three-material decomposition of soft-tissue, bone, and iodine. Image quality and decomposition accuracy were assessed in experiments using a phantom with pairs of bone and iodine inserts (3, 5, 15 and 20 mm) and an anthropomorphic wrist. Results: The designed trajectories improved the sampling distribution from 56% minimum sampling of voxels to 75%. Use of iterative reconstruction (viz., penalized likelihood with edge preserving regularization) in combination with such trajectories resulted in a very low level of artifacts in images of the wrist. For large bone or iodine inserts (>5 mm diameter), the error in the estimated material concentration was <16% for (50 mg/mL) bone and <8% for (5 mg/mL) iodine with strong regularization. For smaller inserts, errors of 20-40% were observed and motivate improved methods for spectral calibration and optimization of the edge-preserving regularizer. Conclusion: Use of PCXDs for three-material decomposition in joint imaging proved feasible through a combination of rotation-translation acquisition trajectories and iterative reconstruction with optimized regularization.

Proceedings Article | 19 March 2014 Paper

Cascaded systems modeling of signal, noise, and DQE for x-ray photon counting detectors

J. Xu, W. Zbijewski, G. Gang, J. Stayman, K. Taguchi, M. Lundqvist, E. Fredenberg, J. Carrino, J. Siewerdsen

Proceedings Volume 9033, 903320 (2014) https://doi.org/10.1117/12.2043515

KEYWORDS: Sensors, Systems modeling, Modulation transfer functions, Signal detection, Imaging systems, Photon counting, Performance modeling, X-rays, Interference (communication), X-ray detectors

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Proceedings Article | 19 March 2013 Paper

Modeling photon-counting detectors for x-ray CT: spectral response and pulse-pileup effects and evaluation using real data

J. Cammin, J. Xu, William Barber, J. Iwanczyk, N. Hartsough, K. Taguchi

Proceedings Volume 8668, 86680R (2013) https://doi.org/10.1117/12.2008077

KEYWORDS: Data modeling, Sensors, Personal protective equipment, X-rays, Attenuators, X-ray detectors, Photodetectors, X-ray computed tomography, Algorithm development, Data acquisition

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Showing 5 of 8 publications

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