Virtual monoenergetic imaging in photon-counting CT of the head and neck

Faraz Farhadi; Pooyan Sahbaee; Jayasai R. Rajagopal; Moozhan Nikpanah; Babak Saboury; Ralf Gutjahr; Nadia M. Biassou; Ritu Shah; Thomas G. Flohr; Ehsan Samei; William F. Pritchard; Ashkan A. Malayeri; David A. Bluemke; Elizabeth C. Jones

doi:10.1016/j.clinimag.2023.08.004

Virtual monoenergetic imaging in photon-counting CT of the head and neck

Faraz Farhadi, Pooyan Sahbaee, Jayasai R. Rajagopal, Moozhan Nikpanah, Babak Saboury, Ralf Gutjahr, Nadia M. Biassou, Ritu Shah, Thomas G. Flohr, Ehsan Samei, William F. Pritchard, Ashkan A. Malayeri, David A. Bluemke, Elizabeth C. Jones

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

2 Scopus citations

Abstract

Purpose: Advantages of virtual monoenergetic images (VMI) have been reported for dual energy CT of the head and neck, and more recently VMIs derived from photon-counting (PCCT) angiography of the head and neck. We report image quality metrics of VMI in a PCCT angiography dataset, expanding the anatomical regions evaluated and extending observer-based qualitative methods further than previously reported. Methods: In a prospective study, asymptomatic subjects underwent contrast enhanced PCCT of the head and neck using an investigational scanner. Image sets of low, high, and full spectrum (Threshold-1) energies; linear mix of low and high energies (Mix); and 23 VMIs (40–150 keV, 5 keV increments) were generated. In 8 anatomical locations, SNR and radiologists' preferences for VMI energy levels were measured using a forced-choice rank method (4 observers) and ratings of image quality using visual grading characteristic (VGC) analysis (2 observers) comparing VMI to Mix and Threshold-1 images. Results: Fifteen subjects were included (7 men, 8 women, mean 57 years, range 46–75). Among all VMIs, SNRs varied by anatomic location. The highest SNRs were observed in VMIs. Radiologists preferred 50–60 keV VMIs for vascular structures and 75–85 keV for all other structures. Cumulative ratings of image quality averaged across all locations were higher for VMIs with areas under the curve of VMI vs Mix and VMI vs Threshold-1 of 0.67 and 0.68 for the first reader and 0.72 and 0.76 for the second, respectively. Conclusion: Preferred keV level and quality ratings of VMI compared to mixed and Threshold-1 images varied by anatomical location.

Original language	English
Pages (from-to)	109-115
Number of pages	7
Journal	Clinical Imaging
Volume	102
DOIs	https://doi.org/10.1016/j.clinimag.2023.08.004
State	Published - Oct 2023
Externally published	Yes

Funding

This study was supported by the National Institutes of Health (NIH) Clinical Center Radiology and Imaging Sciences (RADIS), the NIH Graduate Partnership Program and the NIH Intramural Research Program . The NIH and Siemens Medical Solutions have a Cooperative Research and Development Agreement providing material support, including the photon-counting CT system.

Keywords

Head and neck CT
Photon counting CT
Virtual monoenergetic imaging
Visual grading characteristic

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10.1016/j.clinimag.2023.08.004

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@article{3381090947704f4186fe973071345c18,

title = "Virtual monoenergetic imaging in photon-counting CT of the head and neck",

abstract = "Purpose: Advantages of virtual monoenergetic images (VMI) have been reported for dual energy CT of the head and neck, and more recently VMIs derived from photon-counting (PCCT) angiography of the head and neck. We report image quality metrics of VMI in a PCCT angiography dataset, expanding the anatomical regions evaluated and extending observer-based qualitative methods further than previously reported. Methods: In a prospective study, asymptomatic subjects underwent contrast enhanced PCCT of the head and neck using an investigational scanner. Image sets of low, high, and full spectrum (Threshold-1) energies; linear mix of low and high energies (Mix); and 23 VMIs (40–150 keV, 5 keV increments) were generated. In 8 anatomical locations, SNR and radiologists' preferences for VMI energy levels were measured using a forced-choice rank method (4 observers) and ratings of image quality using visual grading characteristic (VGC) analysis (2 observers) comparing VMI to Mix and Threshold-1 images. Results: Fifteen subjects were included (7 men, 8 women, mean 57 years, range 46–75). Among all VMIs, SNRs varied by anatomic location. The highest SNRs were observed in VMIs. Radiologists preferred 50–60 keV VMIs for vascular structures and 75–85 keV for all other structures. Cumulative ratings of image quality averaged across all locations were higher for VMIs with areas under the curve of VMI vs Mix and VMI vs Threshold-1 of 0.67 and 0.68 for the first reader and 0.72 and 0.76 for the second, respectively. Conclusion: Preferred keV level and quality ratings of VMI compared to mixed and Threshold-1 images varied by anatomical location.",

keywords = "Head and neck CT, Photon counting CT, Virtual monoenergetic imaging, Visual grading characteristic",

author = "Faraz Farhadi and Pooyan Sahbaee and Rajagopal, {Jayasai R.} and Moozhan Nikpanah and Babak Saboury and Ralf Gutjahr and Biassou, {Nadia M.} and Ritu Shah and Flohr, {Thomas G.} and Ehsan Samei and Pritchard, {William F.} and Malayeri, {Ashkan A.} and Bluemke, {David A.} and Jones, {Elizabeth C.}",

note = "Publisher Copyright: {\textcopyright} 2023",

year = "2023",

month = oct,

doi = "10.1016/j.clinimag.2023.08.004",

language = "English",

volume = "102",

pages = "109--115",

journal = "Clinical Imaging",

issn = "0899-7071",

publisher = "Elsevier",

}

TY - JOUR

T1 - Virtual monoenergetic imaging in photon-counting CT of the head and neck

AU - Farhadi, Faraz

AU - Sahbaee, Pooyan

AU - Rajagopal, Jayasai R.

AU - Nikpanah, Moozhan

AU - Saboury, Babak

AU - Gutjahr, Ralf

AU - Biassou, Nadia M.

AU - Shah, Ritu

AU - Flohr, Thomas G.

AU - Samei, Ehsan

AU - Pritchard, William F.

AU - Malayeri, Ashkan A.

AU - Bluemke, David A.

AU - Jones, Elizabeth C.

PY - 2023/10

Y1 - 2023/10

N2 - Purpose: Advantages of virtual monoenergetic images (VMI) have been reported for dual energy CT of the head and neck, and more recently VMIs derived from photon-counting (PCCT) angiography of the head and neck. We report image quality metrics of VMI in a PCCT angiography dataset, expanding the anatomical regions evaluated and extending observer-based qualitative methods further than previously reported. Methods: In a prospective study, asymptomatic subjects underwent contrast enhanced PCCT of the head and neck using an investigational scanner. Image sets of low, high, and full spectrum (Threshold-1) energies; linear mix of low and high energies (Mix); and 23 VMIs (40–150 keV, 5 keV increments) were generated. In 8 anatomical locations, SNR and radiologists' preferences for VMI energy levels were measured using a forced-choice rank method (4 observers) and ratings of image quality using visual grading characteristic (VGC) analysis (2 observers) comparing VMI to Mix and Threshold-1 images. Results: Fifteen subjects were included (7 men, 8 women, mean 57 years, range 46–75). Among all VMIs, SNRs varied by anatomic location. The highest SNRs were observed in VMIs. Radiologists preferred 50–60 keV VMIs for vascular structures and 75–85 keV for all other structures. Cumulative ratings of image quality averaged across all locations were higher for VMIs with areas under the curve of VMI vs Mix and VMI vs Threshold-1 of 0.67 and 0.68 for the first reader and 0.72 and 0.76 for the second, respectively. Conclusion: Preferred keV level and quality ratings of VMI compared to mixed and Threshold-1 images varied by anatomical location.

AB - Purpose: Advantages of virtual monoenergetic images (VMI) have been reported for dual energy CT of the head and neck, and more recently VMIs derived from photon-counting (PCCT) angiography of the head and neck. We report image quality metrics of VMI in a PCCT angiography dataset, expanding the anatomical regions evaluated and extending observer-based qualitative methods further than previously reported. Methods: In a prospective study, asymptomatic subjects underwent contrast enhanced PCCT of the head and neck using an investigational scanner. Image sets of low, high, and full spectrum (Threshold-1) energies; linear mix of low and high energies (Mix); and 23 VMIs (40–150 keV, 5 keV increments) were generated. In 8 anatomical locations, SNR and radiologists' preferences for VMI energy levels were measured using a forced-choice rank method (4 observers) and ratings of image quality using visual grading characteristic (VGC) analysis (2 observers) comparing VMI to Mix and Threshold-1 images. Results: Fifteen subjects were included (7 men, 8 women, mean 57 years, range 46–75). Among all VMIs, SNRs varied by anatomic location. The highest SNRs were observed in VMIs. Radiologists preferred 50–60 keV VMIs for vascular structures and 75–85 keV for all other structures. Cumulative ratings of image quality averaged across all locations were higher for VMIs with areas under the curve of VMI vs Mix and VMI vs Threshold-1 of 0.67 and 0.68 for the first reader and 0.72 and 0.76 for the second, respectively. Conclusion: Preferred keV level and quality ratings of VMI compared to mixed and Threshold-1 images varied by anatomical location.

KW - Head and neck CT

KW - Photon counting CT

KW - Virtual monoenergetic imaging

KW - Visual grading characteristic

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U2 - 10.1016/j.clinimag.2023.08.004

DO - 10.1016/j.clinimag.2023.08.004

M3 - Article

C2 - 37672849

AN - SCOPUS:85169502727

SN - 0899-7071

VL - 102

SP - 109

EP - 115

JO - Clinical Imaging

JF - Clinical Imaging

ER -

Virtual monoenergetic imaging in photon-counting CT of the head and neck

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Keywords

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