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Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association2026; 67(5); e70231; doi: 10.1111/vru.70231

Computed Tomographic Lesion Descriptors in Foals With Hematogenous Osteomyelitis: Interobserver Agreement and Association With Outcome.

Abstract: Computed tomography (CT) is increasingly used to diagnose osteomyelitis in foals, but the prognostic value and interobserver reproducibility of specific CT lesion descriptors remain unclear. This multicenter retrospective study aimed to characterize CT features of hematogenous osteomyelitis in foals using a structured radiologic feature set, assess interobserver agreement, and evaluate associations between CT descriptors and survival to hospital discharge and long-term survival. We hypothesized that CT features considered aggressive, including a long transition zone, permeative or moth-eaten osteolysis, and discontinuous or irregular periosteal reaction, would be negatively associated with survival. Foals diagnosed with osteomyelitis and examined by CT at three tertiary referral centers were included. CT images were independently reviewed by three blinded observers. Interobserver agreement was assessed using Krippendorff's alpha. Associations between clinical variables, CT descriptors, and survival outcomes were evaluated using logistic regression. Fifty-six foals met inclusion criteria. Thirty-six foals (64%) survived to hospital discharge, and 26 of 32 foals (81%) with follow-up data survived long term. Articular involvement (p = 0.04; odds ratio [OR], 0.06; 95% confidence interval [CI], 0.04-0.89) and a long transition zone (p = 0.03; OR, 0.13; 95% CI, 0.23-0.78) were negatively associated with survival to discharge. Lesions at multiple locations were negatively associated with long-term survival (p = 0.03; OR, 0.05; 95% CI, 0.04-0.77). Interobserver agreement ranged from weak to moderate. Associations between individual CT descriptors and survival were limited, highlighting the need for prospective studies and improved standardization of CT lesion descriptors in foals with osteomyelitis.
© 2026 The Author(s). Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.
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Publication Date: 2026-08-26 PubMed ID: 42644767PubMed Central: PMC13510097DOI: 10.1111/vru.70231Google Scholar: Lookup
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  • Journal Article
  • Multicenter Study

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study investigated how specific features seen in CT scans of foals with hematogenous osteomyelitis relate to survival outcomes and how consistently different observers can identify these features.
  • The research found certain CT characteristics, such as involvement of joints and long transition zones in bone lesions, were linked to reduced survival rates, but observer agreement on some CT features was only moderate or weak.

Purpose and Hypothesis

  • The study aimed to:
    • Characterize CT image features of hematogenous osteomyelitis in foals using a defined set of lesion descriptors.
    • Assess how reliably different observers agree when identifying these CT features (interobserver agreement).
    • Evaluate associations between these CT features and survival outcomes both at discharge and in the long term.
  • The researchers hypothesized that aggressive CT features—such as a long transition zone, permeative or moth-eaten osteolysis, and irregular periosteal reactions—would be associated with worse survival outcomes.

Study Design and Methods

  • Multicenter retrospective study including foals diagnosed with hematogenous osteomyelitis who had CT scans performed at three tertiary referral centers.
  • CT images were reviewed independently and blindly by three different observers to assess lesion characteristics without bias.
  • Interobserver agreement was analyzed using Krippendorff’s alpha, a statistical measure of reliability.
  • Logistic regression was used to examine the relationship between clinical variables, CT lesion features, and survival outcomes (both to hospital discharge and long-term survival).

Key Findings

  • 56 foals met inclusion criteria for the study.
  • Survival rates:
    • 64% (36 foals) survived to hospital discharge.
    • 81% of foals with follow-up data (26 out of 32) survived long term.
  • Lesion characteristics associated with worse survival:
    • Articular involvement was significantly linked to lower survival to discharge (p = 0.04; odds ratio 0.06).
    • Presence of a long transition zone in the lesion was also negatively associated with survival to discharge (p = 0.03; odds ratio 0.13).
    • Lesions present in multiple anatomical locations were associated with poorer long-term survival outcomes (p = 0.03; odds ratio 0.05).
  • Interobserver agreement across CT lesion descriptors ranged from weak to moderate, indicating some variability in how observers interpreted the scans.

Interpretation and Implications

  • Some specific CT features — especially joint involvement and long transition zones in lesions — can help predict poorer survival outcomes in foals with hematogenous osteomyelitis.
  • The variability in observer agreement suggests that current CT lesion descriptors lack standardization or clarity, which can affect diagnostic consistency.
  • These findings highlight the need for prospective studies with standardized CT descriptor protocols to improve the prognostic value and reliability of CT in this context.
  • Better consistency in reading CT images could help veterinarians make more informed decisions about treatment and prognosis for affected foals.

Conclusion

  • CT imaging has prognostic relevance in foal osteomyelitis, but current lesion descriptors show limited and variable reliability between observers.
  • Further research should aim to refine CT lesion descriptors and validate them prospectively to enhance both diagnostic accuracy and predictive power.

Cite This Article

APA
Gustafsson K, Longo M, Vanderperren K, Haardt H, Haspeslagh M, Stas E, De Zani D, Buyck C, Robert M, Zani DD. (2026). Computed Tomographic Lesion Descriptors in Foals With Hematogenous Osteomyelitis: Interobserver Agreement and Association With Outcome. Vet Radiol Ultrasound, 67(5), e70231. https://doi.org/10.1111/vru.70231

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: 67
Issue: 5
Pages: e70231
PII: e70231

Researcher Affiliations

Gustafsson, Kajsa
  • Department of Veterinary Medicine and Animal Sciences - DIVAS, University of Milan, Lodi, Italy.
Longo, Maurizio
  • Department of Veterinary Medicine and Animal Sciences - DIVAS, University of Milan, Lodi, Italy.
  • Diagnostic Imaging Unit, CTO Veterinario, Arenzano, Italy.
Vanderperren, Katrien
  • Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Haardt, Hanna
  • Department of Large Animal Surgery, Anaesthesia and Orthopaedics, Ghent University, Merelbeke, Belgium.
Haspeslagh, Maarten
  • Department of Large Animal Surgery, Anaesthesia and Orthopaedics, Ghent University, Merelbeke, Belgium.
Stas, Emanuël
  • Equine Clinic: Surgery and Radiology, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
De Zani, Donatella
  • Department of Veterinary Medicine and Animal Sciences - DIVAS, University of Milan, Lodi, Italy.
Buyck, Camille
  • Centre Hospitalier Vétérinaire Équin de Livet, Livarot-Pays-d'Auge, France.
Robert, Mickaël
  • Centre Hospitalier Vétérinaire Équin de Livet, Livarot-Pays-d'Auge, France.
Zani, Davide D
  • Department of Veterinary Medicine and Animal Sciences - DIVAS, University of Milan, Lodi, Italy.

MeSH Terms

  • Animals
  • Osteomyelitis / veterinary
  • Osteomyelitis / diagnostic imaging
  • Osteomyelitis / pathology
  • Horses
  • Horse Diseases / diagnostic imaging
  • Horse Diseases / pathology
  • Horse Diseases / mortality
  • Tomography, X-Ray Computed / veterinary
  • Retrospective Studies
  • Observer Variation
  • Male
  • Female
  • Reproducibility of Results
  • Prognosis

Conflict of Interest Statement

The authors declare no conflicts of interest.

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