Spectral detector CT-derived virtual non-contrast images: comparison of attenuation values with unenhanced CT

Lakshmi Ananthakrishnan, Prabhakar Rajiah, Richard Ahn, Negin Rassouli, Yin Xi, Todd C. Soesbe, Matthew A. Lewis, Robert E. Lenkinski, John R. Leyendecker, Suhny Abbara

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30 Citations (Scopus)

Abstract

Abstract: Purpose: To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. Abstract: Methods: In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. Abstract: Results: Mean difference between unenhanced and VNC attenuation was <15 HU in 92.6%, <10 HU in 75.2%, and <5 HU in 44.4% of all measurements. Unenhanced and VNC attenuation were equivalent in all tissues except fat using a threshold of <10 HU difference (p < 0.05). No significant variation was seen between phases. In fat, VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84% of arterial phase and 85% of nephrographic phase cases, but only 40% of urographic phase. Abstract: Conclusion: VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.

Original languageEnglish (US)
Pages (from-to)1-8
Number of pages8
JournalAbdominal Radiology
DOIs
StateAccepted/In press - Jan 13 2017

Fingerprint

Fats
Abdominal Subcutaneous Fat
Psoas Muscles
Health Insurance Portability and Accountability Act
Research Ethics Committees
Subcutaneous Fat
Abdominal Aorta
Spleen
Pathology
Kidney
Liver

Keywords

  • Dual energy
  • Dual layer detector
  • SDCT
  • Spectral detector CT
  • Unenhanced versus VNC
  • Virtual non-contrast
  • VNC
  • VNC attenuation

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology
  • Urology
  • Radiological and Ultrasound Technology

Cite this

@article{312d02f7ac1e432996d4edcc9c4b61a2,
title = "Spectral detector CT-derived virtual non-contrast images: comparison of attenuation values with unenhanced CT",
abstract = "Abstract: Purpose: To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. Abstract: Methods: In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. Abstract: Results: Mean difference between unenhanced and VNC attenuation was <15 HU in 92.6{\%}, <10 HU in 75.2{\%}, and <5 HU in 44.4{\%} of all measurements. Unenhanced and VNC attenuation were equivalent in all tissues except fat using a threshold of <10 HU difference (p < 0.05). No significant variation was seen between phases. In fat, VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84{\%} of arterial phase and 85{\%} of nephrographic phase cases, but only 40{\%} of urographic phase. Abstract: Conclusion: VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.",
keywords = "Dual energy, Dual layer detector, SDCT, Spectral detector CT, Unenhanced versus VNC, Virtual non-contrast, VNC, VNC attenuation",
author = "Lakshmi Ananthakrishnan and Prabhakar Rajiah and Richard Ahn and Negin Rassouli and Yin Xi and Soesbe, {Todd C.} and Lewis, {Matthew A.} and Lenkinski, {Robert E.} and Leyendecker, {John R.} and Suhny Abbara",
year = "2017",
month = "1",
day = "13",
doi = "10.1007/s00261-016-1036-9",
language = "English (US)",
pages = "1--8",
journal = "Abdominal Radiology",
issn = "2366-004X",
publisher = "Springer New York",

}

TY - JOUR

T1 - Spectral detector CT-derived virtual non-contrast images

T2 - comparison of attenuation values with unenhanced CT

AU - Ananthakrishnan, Lakshmi

AU - Rajiah, Prabhakar

AU - Ahn, Richard

AU - Rassouli, Negin

AU - Xi, Yin

AU - Soesbe, Todd C.

AU - Lewis, Matthew A.

AU - Lenkinski, Robert E.

AU - Leyendecker, John R.

AU - Abbara, Suhny

PY - 2017/1/13

Y1 - 2017/1/13

N2 - Abstract: Purpose: To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. Abstract: Methods: In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. Abstract: Results: Mean difference between unenhanced and VNC attenuation was <15 HU in 92.6%, <10 HU in 75.2%, and <5 HU in 44.4% of all measurements. Unenhanced and VNC attenuation were equivalent in all tissues except fat using a threshold of <10 HU difference (p < 0.05). No significant variation was seen between phases. In fat, VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84% of arterial phase and 85% of nephrographic phase cases, but only 40% of urographic phase. Abstract: Conclusion: VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.

AB - Abstract: Purpose: To assess virtual non-contrast (VNC) images obtained on a detection-based spectral detector CT scanner and determine how attenuation on VNC images derived from various phases of enhanced CT compare to those obtained from true unenhanced images. Abstract: Methods: In this HIPAA compliant, IRB approved prospective multi-institutional study, 46 patients underwent pre- and post-contrast imaging on a prototype dual-layer spectral detector CT between October 2013 and November 2015, yielding 84 unenhanced and VNC pairs (25 arterial, 39 portal venous/nephrographic, 20 urographic). Mean attenuation was measured by one of three readers in the liver, spleen, kidneys, psoas muscle, abdominal aorta, and subcutaneous fat. Equivalence testing was used to determine if the mean difference between unenhanced and VNC attenuation was less than 5, 10, or 15 HU. VNC image quality was assessed on a 5 point scale. Abstract: Results: Mean difference between unenhanced and VNC attenuation was <15 HU in 92.6%, <10 HU in 75.2%, and <5 HU in 44.4% of all measurements. Unenhanced and VNC attenuation were equivalent in all tissues except fat using a threshold of <10 HU difference (p < 0.05). No significant variation was seen between phases. In fat, VNC overestimated the HU relative to unenhanced images. VNC image quality was rated as excellent or good in 84% of arterial phase and 85% of nephrographic phase cases, but only 40% of urographic phase. Abstract: Conclusion: VNC images derived from novel dual layer spectral detector CT demonstrate attenuation values similar to unenhanced images in all tissues evaluated except for subcutaneous fat. Further study is needed to determine if attenuation thresholds currently used clinically for common pathology should be adjusted, particularly for lesions containing fat.

KW - Dual energy

KW - Dual layer detector

KW - SDCT

KW - Spectral detector CT

KW - Unenhanced versus VNC

KW - Virtual non-contrast

KW - VNC

KW - VNC attenuation

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JO - Abdominal Radiology

JF - Abdominal Radiology

SN - 2366-004X

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