Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. VI. Radiological/pathological correlations.

The research attempted to determine if the seriousness of lung lesions linked to exercise-induced pulmonary bleeding in horses can be foreseen from chest x-rays. The results affirmed a positive correlation with autopsy measurements but predicting the exact lung pathology in individual cases was not possible due to high variance of coded values.

Objective of the Research

• The study’s primary aim was to evaluate whether thoracic radiographs can predict the extent and severity of lung lesions connected with exercise-induced pulmonary haemorrhage (EIPH) in horses. EIPH is a bleeding condition prevalent in racehorses.

Methodology

• Thoracic radiographs were taken from 24 horses with different histories of EIPH. Three radiologists examined each radiograph, blind to the corresponding autopsy results.
• Parameters such as radiographic quality, extent, and intensity of diffuse interstitial opacity were coded subjectively.
• These coded estimates were then compared with coded estimates of lung surface staining from post mortem evaluations. They also compared these metrics with the volume measurements of haemosiderin deposits (iron-storing complex) and bronchial arterial neovascularisation, recorded from lung slices in separate studies.
• The statistical significance between these sets of coded values was tested using the non-parametric Spearman rank correlation test.

Results and Findings

• All coded estimates of lesion severity from radiographs had a positive correlation with post mortem measurements of actual lesion involvement.
• The correlations between opacity of lesions coded from radiographs versus the volume of haemosiderin deposits and bronchial artery neovascularisation were statistically significant (P < 0.05).
• However, the correlations between lesion extent coded from radiographs and the same parameters (haemosiderin deposits and neovascularisation) were just shy of being statistically significant (0.05 < P < 0.1).

Conclusions

• The findings indicate an observable increase in interstitial opacity in relation to the severity of the actual lesion, as seen in the radiographs.
• However, the actual prediction of lung pathology in individual cases based on radiographic criteria was difficult due to the extensive variance of the coded radiographic values.
• Despite these limitations, the authors argue that with a sound radiographic technique and careful selection of criteria, a satisfactory prediction of lesion severity in EIPH cases is possible.