Feasibility of shear wave elastography (2D -SWE) to evaluate cristalline lens in healthy dogs

2D shear wave elastography (2D SWE) is an emerging technique in veterinary medicine able to assess tissue stiffness in a non-invasive way. Nowadays no report is yet available about its application in assessing the mechanical properties of canine lenses.

This study aimed to evaluate the repeatability and reproducibility of 2D SWE in assessing normal lens elasticity in healthy and ageing dogs.

Trans-corneal lens 2D SWE was performed under physical restraint on 33 dogs by two operators who collected triplicate kPa and m/s measures, with the aim to assess reproducibility and reliability of the technique, followed by the evaluation of eventual difference of stiffness in different ages (G1 < 1.5 years, G2 1.5 years-7 years and G3 > 7 years). The project has been approved by the CEISA Ethical Committee (Prot. N. 12/2019 361 CEISA). Written informed consent was obtained by all the owners.

Mean elasticity values were respectively 4.78 ± 1.48 m/s and 74.9 ± 43.7 kPa for the left eye and 4.45 ± 0.98 m/s and 75.9 ± 43.6 kPa for the right eye. Despite a slight difference observed in the measurements obtained in m/s between the two operators, the intra-observer assessment was excellent in the overall population of dogs for both values in KPa and m/s, as well as the inter-observer one (ICC > 0.75). All the sCV% computed evidence a low measurement dispersion (< 12%). Mean lens stiffness for G1 was 3.1 ± 0.5 m/s and 28.9 ± 9.3 kPa, for G2 4.61 ± 0.62 m/s and 65 ± 18.4 kPa and for G3 6.46 ± 0.36 m/s and 126 ± 14.5 kPa; a significant difference P (< 0.001) was detected between all the groups.

It can be concluded that 2D SWE is a rapid and non-invasive US-based technique able to assess lens mechanical properties in companion animals since it is characterized by high reliability and reproducibility, providing also information regarding lens stiffness in aging dogs.