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Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery
Published on: February 20, 2017
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COMPUTED TOMOGRAPHIC MEASUREMENT OF THE MAIN PULMONARY ARTERY TO AORTIC DIAMETER RATIO IN HEALTHY DOGS: A COMPARISON
L Abbigail Granger1, Romain Pariaut1, Jorge Vila1
1Department of Veterinary Clinical Sciences, Lousiana State University School of Veterinary Medicine, Baton Rouge, LA, 70803.
Summary
Computed tomography (CT) measurements of the main pulmonary artery to aortic diameter ratio (MPA:Ao) in dogs are not well established. This study found CT MPA:Ao values differ based on respiration, and the echocardiographic upper limit is not suitable for CT assessment.
Area of Science:
- Veterinary Radiology
- Cardiology
- Pulmonary Hypertension
Background:
- Pulmonary hypertension indicators in dogs using thoracic computed tomography (CT) require further establishment.
- The main pulmonary artery to aortic diameter ratio (MPA:Ao) is a sensitive indicator in human CT studies, but its use in veterinary CT is not well-described.
Purpose of the Study:
- To compare echocardiographic and CT-derived MPA:Ao measurements in dogs.
- To assess the repeatability and reproducibility of CT-based MPA:Ao measurements.
- To evaluate the impact of respiration and contrast on CT MPA:Ao measurements.
Main Methods:
- Ten healthy dogs underwent thoracic CT with three protocols and echocardiography.
- MPA:Ao was measured by three observers across all CT protocols and compared to echocardiography.
- Repeatability and reproducibility were assessed, along with the effect of respiration and contrast.
Main Results:
- The mean MPA:Ao measured via CT was 1.108 ± 0.152.
- CT scan protocols significantly affected MPA:Ao measurements, with expiratory scans yielding lower ratios than inspiratory scans.
- Inspiratory CT scans overestimated MPA:Ao compared to echocardiography (bias = 0.226).
Conclusions:
- The echocardiographically derived upper limit of MPA:Ao (1:1) is not applicable for CT assessment in dogs.
- CT-based MPA:Ao measurement is influenced by respiratory phase, necessitating standardized protocols.
- Further research is needed to establish reliable CT indicators for pulmonary hypertension in dogs.
