Impact of energy threshold on material quantification of contrast agents in photon-counting CT

Jayasai R. Rajagopal; Pooyan Sahbaee; Ehsan Abadi; Ayele H. Negussie; William F. Pritchard; Brad J. Wood; Elizabeth C. Jones; Ehsan Samei

doi:10.1117/12.2512944

Impact of energy threshold on material quantification of contrast agents in photon-counting CT

Jayasai R. Rajagopal, Pooyan Sahbaee, Ehsan Abadi, Ayele H. Negussie, William F. Pritchard, Brad J. Wood, Elizabeth C. Jones, Ehsan Samei

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

2 Scopus citations

Abstract

The purpose of this study was to examine the effect of energy threshold selection on the quantification of contrast agents in photon-counting CT (PCCT). A phantom was devised consisting of vials of iodine (4, 8, 16 mg/mL), gadolinium (4, 8, 16 mg/mL), and bismuth (5, 10, 15 mg/mL) within a cylindrical water container. The phantom was scanned on a prototype photon-counting CT scanner. The detected photons were binned into two energy bins using a fixed lower threshold of 20 keV and an upper threshold that varied between 50 to 90 keV. An image containing all the spectral information (threshold 1) was examined along with both binned images. Images were evaluated for the mean and standard deviation of CT number in each vial and contrast-to-noise ratio (CNR) for each concentration. CT number values in the threshold 1 image remained mostly unchanged as energy threshold was increased. Vials of iodine and gadolinium had slightly higher CT numbers in lower energy bin images than the threshold 1 images, but the percentage difference varied slightly (6-37% for iodine and 5-22% for gadolinium) with energy threshold. In higher energy bin images, CT numbers were lower (20-68% for iodine and 10-59% for gadolinium) than threshold 1 and the difference decreased with increasing energy threshold. For bismuth, the percentage difference in the lower bin decreased (by 11-19%) with energy level while it increased (by 18-23%) in the upper bin. CNR varied only slightly in the lower energy bins and decreased with increasing energy threshold for all materials.

Original language	English
Title of host publication	Medical Imaging 2019
Subtitle of host publication	Physics of Medical Imaging
Editors	Taly Gilat Schmidt, Guang-Hong Chen, Hilde Bosmans
Publisher	SPIE
ISBN (Electronic)	9781510625433
DOIs	https://doi.org/10.1117/12.2512944
State	Published - 2019
Externally published	Yes
Event	Medical Imaging 2019: Physics of Medical Imaging - San Diego, United States Duration: Feb 17 2019 → Feb 20 2019

Publication series

Name	Progress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume	10948
ISSN (Print)	1605-7422

Conference

Conference	Medical Imaging 2019: Physics of Medical Imaging
Country/Territory	United States
City	San Diego
Period	02/17/19 → 02/20/19

Funding

This study was supported by the National Institutes of Health (NIH) Clinical Center Radiology and Imaging Sciences (RADIS), the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and the NIH Intramural Research Program (NIH Z01 1ZID BC011242, and CL040015). The NIH and Siemens Medical Solutions have a Cooperative Research and Development Agreement providing financial and material support including the photon-counting CT system. The content of this manuscript does not necessarily reflect the views or policies of the Department of Health and Human Services, nor do mention of trade names, commercial products, or organizations imply endorsement by the United States Government.

Keywords

Computed tomography
Contrast agent
Material quantification
Photon-counting

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10.1117/12.2512944

Cite this

Rajagopal, J. R., Sahbaee, P., Abadi, E., Negussie, A. H., Pritchard, W. F., Wood, B. J., Jones, E. C., & Samei, E. (2019). Impact of energy threshold on material quantification of contrast agents in photon-counting CT. In T. G. Schmidt, G.-H. Chen, & H. Bosmans (Eds.), Medical Imaging 2019: Physics of Medical Imaging Article 109484N (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 10948). SPIE. https://doi.org/10.1117/12.2512944

@inproceedings{b7623f7e4e594ae6872dece8405df493,

title = "Impact of energy threshold on material quantification of contrast agents in photon-counting CT",

abstract = "The purpose of this study was to examine the effect of energy threshold selection on the quantification of contrast agents in photon-counting CT (PCCT). A phantom was devised consisting of vials of iodine (4, 8, 16 mg/mL), gadolinium (4, 8, 16 mg/mL), and bismuth (5, 10, 15 mg/mL) within a cylindrical water container. The phantom was scanned on a prototype photon-counting CT scanner. The detected photons were binned into two energy bins using a fixed lower threshold of 20 keV and an upper threshold that varied between 50 to 90 keV. An image containing all the spectral information (threshold 1) was examined along with both binned images. Images were evaluated for the mean and standard deviation of CT number in each vial and contrast-to-noise ratio (CNR) for each concentration. CT number values in the threshold 1 image remained mostly unchanged as energy threshold was increased. Vials of iodine and gadolinium had slightly higher CT numbers in lower energy bin images than the threshold 1 images, but the percentage difference varied slightly (6-37% for iodine and 5-22% for gadolinium) with energy threshold. In higher energy bin images, CT numbers were lower (20-68% for iodine and 10-59% for gadolinium) than threshold 1 and the difference decreased with increasing energy threshold. For bismuth, the percentage difference in the lower bin decreased (by 11-19%) with energy level while it increased (by 18-23%) in the upper bin. CNR varied only slightly in the lower energy bins and decreased with increasing energy threshold for all materials.",

keywords = "Computed tomography, Contrast agent, Material quantification, Photon-counting",

author = "Rajagopal, {Jayasai R.} and Pooyan Sahbaee and Ehsan Abadi and Negussie, {Ayele H.} and Pritchard, {William F.} and Wood, {Brad J.} and Jones, {Elizabeth C.} and Ehsan Samei",

note = "Publisher Copyright: {\textcopyright} SPIE. Downloading of the abstract is permitted for personal use only.; Medical Imaging 2019: Physics of Medical Imaging ; Conference date: 17-02-2019 Through 20-02-2019",

year = "2019",

doi = "10.1117/12.2512944",

language = "English",

series = "Progress in Biomedical Optics and Imaging - Proceedings of SPIE",

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Rajagopal, JR, Sahbaee, P, Abadi, E, Negussie, AH, Pritchard, WF, Wood, BJ, Jones, EC & Samei, E 2019, Impact of energy threshold on material quantification of contrast agents in photon-counting CT. in TG Schmidt, G-H Chen & H Bosmans (eds), Medical Imaging 2019: Physics of Medical Imaging., 109484N, Progress in Biomedical Optics and Imaging - Proceedings of SPIE, vol. 10948, SPIE, Medical Imaging 2019: Physics of Medical Imaging, San Diego, United States, 02/17/19. https://doi.org/10.1117/12.2512944

Impact of energy threshold on material quantification of contrast agents in photon-counting CT. / Rajagopal, Jayasai R.; Sahbaee, Pooyan; Abadi, Ehsan et al.
Medical Imaging 2019: Physics of Medical Imaging. ed. / Taly Gilat Schmidt; Guang-Hong Chen; Hilde Bosmans. SPIE, 2019. 109484N (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 10948).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - Impact of energy threshold on material quantification of contrast agents in photon-counting CT

AU - Rajagopal, Jayasai R.

AU - Sahbaee, Pooyan

AU - Abadi, Ehsan

AU - Negussie, Ayele H.

AU - Pritchard, William F.

AU - Wood, Brad J.

AU - Jones, Elizabeth C.

AU - Samei, Ehsan

N1 - Publisher Copyright: © SPIE. Downloading of the abstract is permitted for personal use only.

PY - 2019

Y1 - 2019

N2 - The purpose of this study was to examine the effect of energy threshold selection on the quantification of contrast agents in photon-counting CT (PCCT). A phantom was devised consisting of vials of iodine (4, 8, 16 mg/mL), gadolinium (4, 8, 16 mg/mL), and bismuth (5, 10, 15 mg/mL) within a cylindrical water container. The phantom was scanned on a prototype photon-counting CT scanner. The detected photons were binned into two energy bins using a fixed lower threshold of 20 keV and an upper threshold that varied between 50 to 90 keV. An image containing all the spectral information (threshold 1) was examined along with both binned images. Images were evaluated for the mean and standard deviation of CT number in each vial and contrast-to-noise ratio (CNR) for each concentration. CT number values in the threshold 1 image remained mostly unchanged as energy threshold was increased. Vials of iodine and gadolinium had slightly higher CT numbers in lower energy bin images than the threshold 1 images, but the percentage difference varied slightly (6-37% for iodine and 5-22% for gadolinium) with energy threshold. In higher energy bin images, CT numbers were lower (20-68% for iodine and 10-59% for gadolinium) than threshold 1 and the difference decreased with increasing energy threshold. For bismuth, the percentage difference in the lower bin decreased (by 11-19%) with energy level while it increased (by 18-23%) in the upper bin. CNR varied only slightly in the lower energy bins and decreased with increasing energy threshold for all materials.

AB - The purpose of this study was to examine the effect of energy threshold selection on the quantification of contrast agents in photon-counting CT (PCCT). A phantom was devised consisting of vials of iodine (4, 8, 16 mg/mL), gadolinium (4, 8, 16 mg/mL), and bismuth (5, 10, 15 mg/mL) within a cylindrical water container. The phantom was scanned on a prototype photon-counting CT scanner. The detected photons were binned into two energy bins using a fixed lower threshold of 20 keV and an upper threshold that varied between 50 to 90 keV. An image containing all the spectral information (threshold 1) was examined along with both binned images. Images were evaluated for the mean and standard deviation of CT number in each vial and contrast-to-noise ratio (CNR) for each concentration. CT number values in the threshold 1 image remained mostly unchanged as energy threshold was increased. Vials of iodine and gadolinium had slightly higher CT numbers in lower energy bin images than the threshold 1 images, but the percentage difference varied slightly (6-37% for iodine and 5-22% for gadolinium) with energy threshold. In higher energy bin images, CT numbers were lower (20-68% for iodine and 10-59% for gadolinium) than threshold 1 and the difference decreased with increasing energy threshold. For bismuth, the percentage difference in the lower bin decreased (by 11-19%) with energy level while it increased (by 18-23%) in the upper bin. CNR varied only slightly in the lower energy bins and decreased with increasing energy threshold for all materials.

KW - Computed tomography

KW - Contrast agent

KW - Material quantification

KW - Photon-counting

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BT - Medical Imaging 2019

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Rajagopal JR, Sahbaee P, Abadi E, Negussie AH, Pritchard WF, Wood BJ et al. Impact of energy threshold on material quantification of contrast agents in photon-counting CT. In Schmidt TG, Chen GH, Bosmans H, editors, Medical Imaging 2019: Physics of Medical Imaging. SPIE. 2019. 109484N. (Progress in Biomedical Optics and Imaging - Proceedings of SPIE). doi: 10.1117/12.2512944

Impact of energy threshold on material quantification of contrast agents in photon-counting CT

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