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Can iterative reconstruction algorithms replace tube loading compensation in low kVp hepatic CT? : Subjective versus objective image quality

Holmquist, Fredrik LU ; Söderberg, Marcus LU orcid ; Nyman, Ulf LU ; Fält, Tobias LU ; Siemund, Roger LU and Geijer, Mats LU (2020) In Acta Radiologica Open 9(3).
Abstract

Background: Hepatic computed tomography (CT) with decreased peak kilovoltage (kVp) may be used to reduce contrast medium doses in patients at risk of contrast-induced acute kidney injury (CI-AKI); however, it increases image noise. To preserve image quality, noise has been controlled by X-ray tube loading (mAs) compensation (TLC), i.e. increased mAs. Another option to control image noise would be to use iterative reconstructions (IR) algorithms without TLC (No-TLC). It is unclear whether this may preserve image quality or only reduce image noise.

Purpose: To evaluate image quality of 80 kVp hepatic CT with TLC and filtered back projection (FBP) compared with 80 kVp with No-TLC and IR algorithms (SAFIRE 3 and 5) in patients with... (More)

Background: Hepatic computed tomography (CT) with decreased peak kilovoltage (kVp) may be used to reduce contrast medium doses in patients at risk of contrast-induced acute kidney injury (CI-AKI); however, it increases image noise. To preserve image quality, noise has been controlled by X-ray tube loading (mAs) compensation (TLC), i.e. increased mAs. Another option to control image noise would be to use iterative reconstructions (IR) algorithms without TLC (No-TLC). It is unclear whether this may preserve image quality or only reduce image noise.

Purpose: To evaluate image quality of 80 kVp hepatic CT with TLC and filtered back projection (FBP) compared with 80 kVp with No-TLC and IR algorithms (SAFIRE 3 and 5) in patients with eGFR <45 mL/min.

Material and Methods: Forty patients (BMI 18-32 kg/m2) were examined with both protocols following injection of 300 mg I/kg. Hepatic attenuation, image noise, enhancement, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were evaluated for each patient.

Results: Comparing TLC/FBP with No-TLC/IR-S5, there were no significant differences regarding hepatic attenuation, image noise, enhancement, SNR and CNR: 114 vs. 115 HU, 14 vs. 14 HU, 55 vs. 57 HU, 8.0 vs. 8.4, and 3.8 vs. 4.0 in median, respectively. No-TLC/IR-S3 resulted in higher image noise and lower SNR and CNR than TLC/FBP. Subjective image quality scoring with visual grading showed statistically significantly inferior scores for IR-S5 images.

Conclusion: CT of 80 kVp to reduce contrast medium dose in patients at risk of CI-AKI combined with IR algorithms with unchanged tube loading to control image noise does not provide sufficient diagnostic quality.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Radiologica Open
volume
9
issue
3
pages
9 pages
publisher
SAGE Publications
external identifiers
  • pmid:32206344
ISSN
2058-4601
DOI
10.1177/2058460120910575
language
English
LU publication?
yes
additional info
© The Foundation Acta Radiologica 2020.
id
e7b2b467-836c-4216-bb1e-660064c112f5
date added to LUP
2021-01-07 23:17:52
date last changed
2021-01-08 16:42:02
@article{e7b2b467-836c-4216-bb1e-660064c112f5,
  abstract     = {{<p>Background: Hepatic computed tomography (CT) with decreased peak kilovoltage (kVp) may be used to reduce contrast medium doses in patients at risk of contrast-induced acute kidney injury (CI-AKI); however, it increases image noise. To preserve image quality, noise has been controlled by X-ray tube loading (mAs) compensation (TLC), i.e. increased mAs. Another option to control image noise would be to use iterative reconstructions (IR) algorithms without TLC (No-TLC). It is unclear whether this may preserve image quality or only reduce image noise.</p><p>Purpose: To evaluate image quality of 80 kVp hepatic CT with TLC and filtered back projection (FBP) compared with 80 kVp with No-TLC and IR algorithms (SAFIRE 3 and 5) in patients with eGFR &lt;45 mL/min.</p><p>Material and Methods: Forty patients (BMI 18-32 kg/m2) were examined with both protocols following injection of 300 mg I/kg. Hepatic attenuation, image noise, enhancement, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were evaluated for each patient.</p><p>Results: Comparing TLC/FBP with No-TLC/IR-S5, there were no significant differences regarding hepatic attenuation, image noise, enhancement, SNR and CNR: 114 vs. 115 HU, 14 vs. 14 HU, 55 vs. 57 HU, 8.0 vs. 8.4, and 3.8 vs. 4.0 in median, respectively. No-TLC/IR-S3 resulted in higher image noise and lower SNR and CNR than TLC/FBP. Subjective image quality scoring with visual grading showed statistically significantly inferior scores for IR-S5 images.</p><p>Conclusion: CT of 80 kVp to reduce contrast medium dose in patients at risk of CI-AKI combined with IR algorithms with unchanged tube loading to control image noise does not provide sufficient diagnostic quality.</p>}},
  author       = {{Holmquist, Fredrik and Söderberg, Marcus and Nyman, Ulf and Fält, Tobias and Siemund, Roger and Geijer, Mats}},
  issn         = {{2058-4601}},
  language     = {{eng}},
  number       = {{3}},
  publisher    = {{SAGE Publications}},
  series       = {{Acta Radiologica Open}},
  title        = {{Can iterative reconstruction algorithms replace tube loading compensation in low kVp hepatic CT? : Subjective versus objective image quality}},
  url          = {{http://dx.doi.org/10.1177/2058460120910575}},
  doi          = {{10.1177/2058460120910575}},
  volume       = {{9}},
  year         = {{2020}},
}