Multi-Detector Helical Computer Tomography, Transrectal Ultrasonography and Histology of the Lumbosacral Area: A Comparative Study in Warmblood Horse Cadavers.

Pain arising from the lumbosacral region is a recognized cause of poor performance and impaired welfare in horses. However, structural changes in the intertransverse joints (ITJs), lumbar articular process joints (APJs), and lumbosacral intervertebral discs (LSDs) may also occur in asymptomatic horses, complicating interpretation of imaging findings.This study evaluated these structures in 14 middle-aged Warmblood cadavers that were not lame according to the owners prior the onset of the problem that resulted in euthanasia or slaughter and correlated ultrasonographic (US) and computed tomographic (CT) findings with histopathology. Transrectal US was used to assess ITJs and LSDs, followed by helical CT. Histological examination was performed on randomly selected specimens (ITJs n = 13, APJs n = 5, LSDs n = 5). Imaging and histological scores were analyzed using Spearman's rank correlation. Mild imaging abnormalities were common across all structures. In intertransverse joints, CT findings correlated significantly with histological scores (ρ = 0.679, p = 0.011), whereas US findings did not. APJs had mild CT changes without significant association with histology. LSDs had subtle imaging changes, with a significant correlation between US and CT scores (ρ = 0.748, p < 0.01) but not with histopathology. Overall, mild imaging changes were frequent and may reflect adaptive or early maladaptive modeling rather than clinically relevant disease.