Comparison of radiographic and computed tomographic images of the lungs in healthy neonatal foals.

This research focuses on a comparison of different imaging techniques, specifically computed tomographic (CT) images and radiographic images, of the lungs in healthy newborn foals, aiming to determine if there’s a connection between measurements of lung attenuation from the CT images and the gas levels in the blood (Paco2 and Pao2).

Study Design and Methods

• The study involved six healthy Standardbred foals all under 14 days old.
• Both thoracic CT images and radiographic views were acquired from each foal while they were sedated and positioned in sternal recumbency (lying on their chest)
• The CT and radiographic images were evaluated for changes or abnormalities in the lung regions. This assessment was made using a subjective scoring system by three separate investigators.
• A quantitative analysis was also conducted on the CT images.
• To investigate any relationship between lung attenuation and gas levels in blood, measurements of Pao2 and Paco2 were performed before sedation, after sedation but before the CT, and after the CT but before radiography.

Study Findings

• There was strong interobserver agreement for CT image scoring of 0.73, and a fair agreement for radiographic image scoring of 0.65.
• Intraobserver agreement was near perfect for both CT (0.97) and radiographic (0.94) image scoring.
• All the foals showed increased CT attenuation and radiographic changes. These changes were largely concentrated in the caudoventral portion of the lungs.
• Radiographic scores were significantly lower than CT image scores.
• A strong positive correlation (r = 0.872) between lung attenuation and CT image score was observed.
• A minor increase in Paco2 was noted but was not considered clinically relevant, while no significant changes in Pao2 were detected.

Study Conclusions

• The results suggested that interpreting CT images is less subjective than interpreting radiographic images.
• This study’s findings may assist in the evaluation of CT and radiographic images of young foals suffering from respiratory tract disease.