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Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association2019; 61(2); 137-146; doi: 10.1111/vru.12823

Standing CT of the equine head: Reducing radiation dose maintains image quality.

Abstract: Multiple published studies involving computed tomographic (CT) examinations of the equine head utilise a wide range of mAs parameters for image acquisition. This prospective, experimental study assessed the effects of lowering mAs during CT image acquisition on image quality and scatter radiation on 10 cadaver equine heads. Each head was scanned three times at 300, 225, and 150 mAs, with all other scanning parameters remaining constant between series. An anthropomorphic phantom was positioned adjacent to each equine head during image acquisition, mimicking a human bystander, with an ionization chamber attached to the phantom at eye level. Each series was reconstructed using filtered back projection, using medium (H30) and high (H80) frequency reconstruction algorithms. Quantitative image quality assessment was performed by calculating signal to noise ratio (SNR) and contrast to noise ratio (CNR). Two qualitative image quality assessments were performed independently by three blinded board certified veterinary radiologists with a 4 week interval, using a visual grade analysis model adapted from peer reviewed medical literature. Ionization chamber measurements, calculated volume CT dose index (CTDIvol), and dose-length product (DLP) were recorded. Halving radiation dose during image acquisition from 300 to 150mAs resulted in comparable image quality between series. There was a statistically significant and linear relationship between mAs and scatter radiation to the bystander; halving mAs during image acquisition resulted in halving of scatter radiation. Results of this cadaveric study support the use of lower mAs settings during standing CT examinations of the equine head.
© 2019 American College of Veterinary Radiology.
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Publication Date: 2019-12-11 PubMed ID: 31823453DOI: 10.1111/vru.12823Google Scholar: Lookup
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  • Journal Article

Summary

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The research article discusses an experimental study conducted to test the effects of lowering mAs during Computed Tomographic (CT) imaging of dead horse heads on image quality and scatter radiation, revealing that reducing radiation doses does not compromise the image quality.

Overview of Research

  • The research study involved conducting computed tomographic (CT) examinations of ten equine (horse) heads that had been previously deceased.
  • The horse heads were each scanned three times, at 300, 225, and 150 mAs, while the rest of the scanning parameters remained constant in all the series.
  • Use of a human-like (anthropomorphic) model placed next to each horse head mimicked how a human bystander would be affected by radiation during the scan. This model had an ionization chamber attached to it at eye level.

Image Reconstruction

  • The images from each scan series were reconstructed using a filtered back projection technique and two different frequency reconstruction algorithms (medium H30 and high H80).
  • Quantitative assessments of the image quality were performed by calculating signal to noise ratio (SNR) and contrast to noise ratio (CNR), enabling the researchers to compare the image quality across different mAs settings.

Image Quality Assessment

  • Qualitative assessments of the image quality were also done independently by three blindfolded, certified veterinary radiologists at an interval of four weeks, using a visual grade analysis model adapted from peer-reviewed medical literature.
  • The assessments recorded the measurements from the ionization chamber, the calculated volume CT dose index (CTDIvol), and the dose-length product (DLP).
  • The study found a statistical relationship between mAs and scatter radiation to the bystander. Reducing mAs resulted in a corresponding decrease in the scatter radiation, without compromising image quality.
  • The finding substantiates the use of lower mAs settings during standing CT examinations of equine heads, which can help reduce the radiation exposure to those present during the scans.

Cite This Article

APA
Davies T, Skelly C, Puggioni A, D'Helft C, Connolly S, Hoey S. (2019). Standing CT of the equine head: Reducing radiation dose maintains image quality. Vet Radiol Ultrasound, 61(2), 137-146. https://doi.org/10.1111/vru.12823

Publication

Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
ISSN: 1740-8261
NlmUniqueID: 9209635
Country: England
Language: English
Volume: 61
Issue: 2
Pages: 137-146

Researcher Affiliations

Davies, Thomas
  • Diagnostic Imaging Department, UCD Veterinary Hospital, University College Dublin, Dublin, Ireland.
Skelly, Cliona
  • Diagnostic Imaging Department, UCD Veterinary Hospital, University College Dublin, Dublin, Ireland.
Puggioni, Antonella
  • Diagnostic Imaging Department, UCD Veterinary Hospital, University College Dublin, Dublin, Ireland.
D'Helft, Catherine
  • Diagnostic Imaging Department, UCD Veterinary Hospital, University College Dublin, Dublin, Ireland.
Connolly, Susan
  • Whitethorn, Dublin, Ireland.
Hoey, Seamus
  • Diagnostic Imaging Department, UCD Veterinary Hospital, University College Dublin, Dublin, Ireland.

MeSH Terms

  • Algorithms
  • Animals
  • Female
  • Head / diagnostic imaging
  • Horses / anatomy & histology
  • Male
  • Observer Variation
  • Phantoms, Imaging
  • Prospective Studies
  • Radiation Dosage
  • Radiographic Image Interpretation, Computer-Assisted
  • Signal-To-Noise Ratio
  • Tomography, X-Ray Computed / methods
  • Tomography, X-Ray Computed / veterinary

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Citations

This article has been cited 3 times.
  1. Stieger-Vanegas SM, Hanna AL. The Role of Computed Tomography in Imaging Non-neurologic Disorders of the Head in Equine Patients. Front Vet Sci 2022;9:798216.
    doi: 10.3389/fvets.2022.798216pubmed: 35321060google scholar: lookup
  2. Gaida JL, Steinberg T, Stieger-Vanegas SM, Merle R, Lischer CJ. Equine Standing Multidetector Computed Tomography of the Distal Thoracic Limb and Tarsus Has a Lower Cumulative Radiation Dose than Digital Radiography. Vet Radiol Ultrasound 2025 Jul;66(4):e70049.
    doi: 10.1111/vru.70049pubmed: 40420323google scholar: lookup
  3. Yoon J, Lee C. Conversion factors to derive organ doses for canine subjects undergoing CT examinations. Vet Radiol Ultrasound 2021 Jul;62(4):421-428.
    doi: 10.1111/vru.12979pubmed: 33987905google scholar: lookup
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