Comparison of Low Dose Performance of Photon-Counting and Energy Integrating CT

Jayasai R. Rajagopal; Faraz Farhadi; Justin Solomon; Pooyan Sahbaee; Babak Saboury; William F. Pritchard; Elizabeth C. Jones; Ehsan Samei

doi:10.1016/j.acra.2020.07.033

Comparison of Low Dose Performance of Photon-Counting and Energy Integrating CT

Jayasai R. Rajagopal, Faraz Farhadi, Justin Solomon, Pooyan Sahbaee, Babak Saboury, William F. Pritchard, Elizabeth C. Jones, Ehsan Samei

Multiscale Biomedical Systems

Research output: Contribution to journal › Article › peer-review

62 Scopus citations

Abstract

Rationale and Objectives: The purpose of this study was to investigate the potential of photon-counting CT (PCCT) to improve quantitative image quality for low dose imaging compared to energy-integrating detector CT (EID CT). Materials and Methods: An investigational scanner (Siemens, Germany) with PCCT and EID CT subsystems was used to compare image quality performance at four dose levels: 1.7, 2, 4, 6 mGy CTDI_vol, all at or below current dose values used for conventional abdominal CT. A CT quality control phantom with a homogeneous section for noise measurements and a section with cylindrical inserts of air (−910 HU), polystyrene (50 HU), acrylic (205 HU), and Teflon (1000 HU) was imaged and characterized in terms of noise, resolution, contrast-to-noise ratio (CNR), and detectability index. A second phantom with a 30 cm diameter was also imaged containing iodine solutions ranging from 0.125 to 8 mg I/mL. CNR of the iodine vials was computed as a function of CT dose and iodine concentration. Results: With resolution unaffected by dose in both PCCT and EID CT, PCCT images exhibited 22.1-24.0% improvement in noise across dose levels evaluated. This noise improvement translated into a 29-41% improvement in CNR and 20-36% improvement in detectability index. For iodine contrast, PCCT images had a higher CNR for all combinations of iodine contrast and dose evaluated. Conclusion: For the conditions studied, PCCT exhibited superior image quality compared to EID CT. For iodine detection, PCCT offered a notable advantage with improved CNR at all doses and iodine concentration levels.

Original language	English
Pages (from-to)	1754-1760
Number of pages	7
Journal	Academic Radiology
Volume	28
Issue number	12
DOIs	https://doi.org/10.1016/j.acra.2020.07.033
State	Published - Dec 2021

Funding

The authors thank Paul Wakim for statistics consultation. 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), NIH Graduate Partnership Program , 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 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. The authors thank Paul Wakim for statistics consultation. 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), NIH Graduate Partnership Program, 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 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
Image quality
Low dose
Photon counting

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10.1016/j.acra.2020.07.033

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title = "Comparison of Low Dose Performance of Photon-Counting and Energy Integrating CT",

abstract = "Rationale and Objectives: The purpose of this study was to investigate the potential of photon-counting CT (PCCT) to improve quantitative image quality for low dose imaging compared to energy-integrating detector CT (EID CT). Materials and Methods: An investigational scanner (Siemens, Germany) with PCCT and EID CT subsystems was used to compare image quality performance at four dose levels: 1.7, 2, 4, 6 mGy CTDIvol, all at or below current dose values used for conventional abdominal CT. A CT quality control phantom with a homogeneous section for noise measurements and a section with cylindrical inserts of air (−910 HU), polystyrene (50 HU), acrylic (205 HU), and Teflon (1000 HU) was imaged and characterized in terms of noise, resolution, contrast-to-noise ratio (CNR), and detectability index. A second phantom with a 30 cm diameter was also imaged containing iodine solutions ranging from 0.125 to 8 mg I/mL. CNR of the iodine vials was computed as a function of CT dose and iodine concentration. Results: With resolution unaffected by dose in both PCCT and EID CT, PCCT images exhibited 22.1-24.0% improvement in noise across dose levels evaluated. This noise improvement translated into a 29-41% improvement in CNR and 20-36% improvement in detectability index. For iodine contrast, PCCT images had a higher CNR for all combinations of iodine contrast and dose evaluated. Conclusion: For the conditions studied, PCCT exhibited superior image quality compared to EID CT. For iodine detection, PCCT offered a notable advantage with improved CNR at all doses and iodine concentration levels.",

keywords = "Computed tomography, Image quality, Low dose, Photon counting",

author = "Rajagopal, {Jayasai R.} and Faraz Farhadi and Justin Solomon and Pooyan Sahbaee and Babak Saboury and Pritchard, {William F.} and Jones, {Elizabeth C.} and Ehsan Samei",

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Comparison of Low Dose Performance of Photon-Counting and Energy Integrating CT

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