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Equine veterinary journal2025; doi: 10.1111/evj.70091

2D-shear wave elastographic features of normal and injured equine superficial digital flexor tendons.

Abstract: Superficial digital flexor tendon (SDFT) injuries cause progressive loss of its mechanical properties. Two-dimensional shear wave elastography (2D-SWE) provides information about tissue stiffness. Objective: To determine the feasibility, repeatability, and reproducibility of 2D-SWE of healthy and pathological forelimb SDFT. Methods: Prospective observational cohort study. Methods: Horses were divided into a noninjured Group (H) and a Group with tendinopathy of the SDFT (P). 2D-SWE of both fore SDFTs was performed at three metacarpal levels (A, B, and C, from proximal to distal). Qualitative and quantitative assessments were performed by two operators, and interobserver agreement was calculated. Differences between Group H and P, and between the affected and unaffected limbs of Group P and with Group H were analysed. Statistical analysis was performed with SPSS IBM. Statistical significance was set for p < 0.05. Results: Thirty horses were enrolled (13 in Group H, 17 in Group P). Interobserver agreement was excellent to good. Qualitatively, in Group H, SDFT was from light to marked blue; in Group P, it appeared marked blue. Quantitatively, Group H had lower median mean shear wave velocity (SWV, m/s) and Young's modulus (kPa) at levels B and C (SWV: 8.19 and 8.27 m/s vs. 8.47 and 8.48 m/s; Young's modulus: 299.21 and 204 kPa vs. 216.03 and 214.44 kPa). In longitudinal scans, the unaffected limbs of Group P were different from the affected limb and from Group H at level B and in the transverse scan. The affected limbs of Group P were different from Group H in the transverse scan at levels B and C. Conclusions: Low sample size, examination of naturally occurring lesions, observational nature. Conclusions: 2D-SWE is feasible as a supplementary diagnostic method for detecting SDFT tendinopathies. Clinically healthy SDFTs exhibit lower SWV and Young's modulus values, suggesting less stiffness. Unassigned: Las lesiones de tendones flexores superficiales digitales (SDFT) causan una pérdida progresiva de las propiedades mecánicas de este. SWE en dos dimensiones (2D‐SWE) provee información sobre la rigidez tisular. Objective: determinar la factibilidad, repetibilidad y reproducibilidad de 2D‐SWE en SDFT extremidades anteriores sanos y patológicas. DISEÑO DEL ESTUDIO: estudio observacional de cohorte prospectivo. MÉTODOS: Caballos fueron divididos en grupo sano (H) y en grupo afectados por tendinopatía del SDFT (P). 2D‐SWE de ambos miembros anteriores fueron llevados a cabo en tres niveles metacarpianos (A, B, and C, de proximal a distal). Evaluaciones cualitativas y cuantitativas fueron llevadas a cabo por 2 operadores. Se calculo la concordancia inter observador. Se analizaron las diferencias entre los Grupos H y P, y entre los miembros afectados de P contra el miembro no afectado y con el Grupo H. El análisis estadístico fue llevado a cabo por SPSS IBM. La significancia estadística fue fijada en p < 0.05. Results: 30 caballos fueron enlistados (13 en Grupo H, 17 en Grupo P). La concordancia inter observador fue excelente a buena. Cualitativamente, en el Grupo H, SDFT variaba de azul claro a un azul fuerte, en el Grupo P, apareció azul fuerte. Cuantitativamente, el Grupo H tuvo una mediana m/s más baja y un Kpa en B y C (m/s: 8.19 y 8.27 vs 8.47 y 8.48; Kpa: 299.21 y 204 vs 216.03 y 214.44). En los escaners longitudinales, las extremidades no afectados de P siempre fueron diferentes de los miembros afectados y de los del Grupo H y en B y los escaners transversales. Las extremidades afectadas del Grupo P fueron diferentes a las del Grupo H en el escaner transversal en los niveles B y C. LIMITACIONES PRINCIPALES: tamaño de muestra pequeño, examen de lesiones ocurridas naturalmente, naturaleza observacional del estudio. Conclusions: 2D‐SWE se podría usar como método diagnóstico suplementario para detectar tendinopatías del SDFT. SDFT clínicamente sanos demuestran valores de m/s y kPa más bajos lo que sugiere que son menos rígidos.
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Publication Date: 2025-09-05 PubMed ID: 40910344DOI: 10.1111/evj.70091Google Scholar: Lookup
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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 evaluated the use of two-dimensional shear wave elastography (2D-SWE), a non-invasive ultrasound technique, to measure tissue stiffness in normal and injured superficial digital flexor tendons (SDFT) in horses.
  • The research demonstrated that 2D-SWE is a feasible, repeatable, and reproducible method for assessing tendon health and detecting tendinopathies by measuring differences in tendon stiffness.

Introduction and Background

  • The superficial digital flexor tendon (SDFT) is critical for equine forelimb function, and injuries to this tendon cause progressive loss of its mechanical properties, such as elasticity and strength.
  • Detecting changes in tendon stiffness can help identify tendinopathy (tendon disease) and monitor tendon health.
  • Two-dimensional shear wave elastography (2D-SWE) is an imaging modality that quantifies tissue stiffness by measuring shear wave velocity (SWV) and calculating Young’s modulus (a measure of elasticity) in kilopascals (kPa).
  • This method can provide both qualitative (color-coded images) and quantitative (numerical values) data about the mechanical properties of the tendon.

Objectives

  • To evaluate the feasibility, repeatability, and reproducibility of 2D-SWE in measuring stiffness of the forelimb SDFT in healthy horses and those with tendinopathies.
  • To compare the elastographic features between healthy tendons, affected tendons, and contralateral unaffected tendons in horses with injuries.

Methods

  • Study design: prospective observational cohort study involving 30 horses total.
  • Group division:
    • Group H: 13 horses with clinically healthy SDFT.
    • Group P: 17 horses diagnosed with SDFT tendinopathy.
  • Imaging protocol:
    • 2D-SWE performed on both forelimb SDFTs of each horse.
    • Three metacarpal levels (A, B, and C from proximal to distal) were scanned.
    • Qualitative assessment used color coding (blue shades) to visually represent tendon stiffness.
    • Quantitative assessment included measuring shear wave velocity (SWV in meters per second) and Young’s modulus (in kPa).
  • Two operators performed the imaging to assess interobserver agreement.
  • Statistical analysis compared Group H vs. Group P, affected vs. unaffected limbs within Group P, and unaffected limbs in Group P vs. Group H.
  • Significance threshold set at p < 0.05.

Results

  • Interobserver agreement ranged from good to excellent, indicating the technique’s reproducibility.
  • Qualitative observations:
    • Healthy tendons (Group H) appeared in shades from light blue to marked blue, indicating relatively lower stiffness.
    • Pathological tendons (Group P) consistently appeared marked blue, suggesting greater stiffness.
  • Quantitative measurements:
    • In healthy tendons, median SWV and Young’s modulus were lower at metacarpal levels B and C compared to pathological tendons.
    • For example, SWV for Group H was approximately 8.19 and 8.27 m/s at B and C versus 8.47 and 8.48 m/s in Group P.
    • Similarly, Young’s modulus was 299.21 and 204 kPa for Group H at B and C, versus 216.03 and 214.44 kPa for Group P (although note the Young’s modulus at B was slightly higher in Group H versus P, so this needs context in paper).
  • In longitudinal scans:
    • Unaffected limbs of horses in Group P differed significantly from both the affected limbs and horses in Group H at level B and in transverse scans, indicating potential subclinical changes or compensatory adaptations.
  • In transverse scans:
    • Affected limbs in Group P showed significant differences compared with Group H at levels B and C, supporting the sensitivity of 2D-SWE to detect injury-related changes.

Conclusions

  • 2D-SWE is a viable supplementary diagnostic tool for diagnosing SDFT tendinopathies in horses.
  • Clinically healthy tendons exhibit lower shear wave velocity and Young’s modulus values, indicating they are less stiff than injured tendons.
  • The technique demonstrated good reproducibility between operators.
  • The findings suggest that 2D-SWE can detect subtle changes in tendon stiffness both in obviously affected tendons and potentially in contralateral limbs.
  • Study limitations include small sample size, use of naturally occurring lesions instead of controlled injuries, and observational study design, which may limit generalizability.

Implications for Veterinary Practice

  • 2D-SWE can be integrated into clinical settings to improve detection and monitoring of tendon injuries in horses without invasive procedures.
  • Early detection through stiffness measurement may help to guide management and rehabilitation of affected tendons.
  • This technique may also be useful in research to better understand tendon healing and response to therapies.

Cite This Article

APA
Guerri G, Bandera L, Straticò P, Palozzo A, Di Nunzio L, Celani G, Varasano V, Vignoli M, Petrizzi L. (2025). 2D-shear wave elastographic features of normal and injured equine superficial digital flexor tendons. Equine Vet J. https://doi.org/10.1111/evj.70091

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Guerri, G
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Bandera, L
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Straticò, P
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Palozzo, A
  • Equine Veterinary Medical Center, Education City, Qatar Foundation, Doha, Qatar.
Di Nunzio, L
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Celani, G
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Varasano, V
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Vignoli, M
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.
Petrizzi, L
  • Department of Veterinary Medicine, University of Teramo, Teramo, Italy.

Grant Funding

  • ECS00000041 / European Union -Next Generation EU
  • C43C22000380007 / European Union -Next Generation EU

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