Fluoroscopic Estimation of Thoracic Dimensional Changes in Healthy Dogs

Area of Science:

• Veterinary medicine
• Respiratory physiology
• Diagnostic imaging

Background:

• Assessing lung mechanics typically requires complex, inaccessible equipment.
• A simpler method to measure lung area changes during breathing could serve as a surrogate for lung compliance.

Purpose of the Study:

• To evaluate fluoroscopy for determining the percentage change in thoracic and lung areas in healthy dogs.

Main Methods:

• A prospective study involving 44 healthy dogs.
• Fluoroscopic recordings of resting respiration captured peak inspiratory and expiratory frames.
• Quantified pixel counts to measure thoracic and lung (hemithorax) areas during respiration.
• Calculated average percent change and established reference ranges.

Main Results:

• Median percent change in total thoracic area was 12.5% (95% CI, 8.9-24.0%).
• Median percent change in hemithorax lung area was significantly higher at 20.8% (95% CI, 14.3-37.6%).
• Measurements correlated with body weight but not age, sex, conformation, BCS, or breed.

Conclusions:

• Fluoroscopy offers a noninvasive, repeatable method for assessing respiratory-induced lung area changes in dogs.
• Results indicate a need for body weight correction in these measurements.
• Further investigation in dogs with respiratory diseases is necessary to establish clinical utility.