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Updated: Feb 14, 2026

Training Dogs for Awake, Unrestrained Functional Magnetic Resonance Imaging
Published on: October 13, 2019
Comparative, multidimensional imaging of patent ductus arteriosus and a proposed update to the morphology
Kelley R Doocy1, Ashley B Saunders1, Sonya G Gordon1
1Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas.
Background:
Accurately assessing the morphology and shape of the patent ductus arteriosus (PDA) and obtaining measurements are important to avoid procedural complications.
Objectives:
To characterize and compare PDA morphology, shape, and dimensions with angiography and echocardiography.
Animals:
25 client-owned dogs with echocardiographically confirmed PDA.
Methods:
Prospective case series. Imaging consisted of single plane angiography, transthoracic echocardiography from the right (TTE-R) and left (TTE-L), and two-dimensional, biplane, and three-dimensional transesophageal echocardiography (TEE-2D and TEE-3D). Measurements included angiographic minimal ductal diameter (MDD), echocardiographic pulmonary ostium in a single dimension (TTE-R, TTE-L, and TEE-2D) and in perpendicular dimensions (TEE-3D) with similar measurements of the ampulla 3 mm above the MDD or pulmonary ostium. The morphology and shape of the PDA were characterized.
Results:
Catheter-based occlusion (N = 20) and surgical ligation (N = 5) were performed without complication. Angiographic morphology was classified as type II (N = 19), type III (N = 1), and other (N = 1). Angiographic MDD and TEE-2D pulmonary ostium measurements were significantly (P = .008) but weakly correlated (r = .56); similar relationships were found for ampulla diameter measurements (P < .0001; r = .75). In general, TEE-2D did not correlate with other imaging modalities measurements. Based on TEE-3D measurements, the majority of pulmonary ostium (17/24; 71%) and ampulla (19/24; 79%) were oval.
Conclusions And Clinical Importance:
Measurements using different imaging modalities are not interchangeable. TEE-3D provided an en face view of the PDA that cannot be replicated with other echocardiographic techniques and demonstrated an oval shape in the majority of dogs. We propose an update to the current classification system to include additional PDA morphologies.
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