CT and MRI Features of Aortic Body Paragangliomas in 44 Dogs

Area of Science:

• Veterinary Radiology
• Canine Oncology
• Comparative Pathology

Background:

• Aortic body paragangliomas (ABPs) are the most frequent tumors at the heart base in dogs.
• While typically benign, ABPs can exhibit malignant behavior, including local invasion and metastasis.
• Detailed computed tomography (CT) and magnetic resonance imaging (MRI) descriptions for canine ABPs are limited.

Purpose of the Study:

• To characterize the CT and MRI findings of benign and malignant aortic body paragangliomas in dogs.
• To identify imaging features that differentiate between benign and malignant ABPs.
• To assess the association of imaging findings with local invasion and metastasis.

Main Methods:

• Retrospective review of 44 dogs with confirmed aortic body paragangliomas.
• Analysis of 43 computed tomography (CT) scans and 3 magnetic resonance imaging (MRI) studies.
• Correlation of imaging features with histopathological diagnosis, local invasion, and metastatic status.

Main Results:

• CT findings included heterogeneous contrast enhancement, well-defined margins, lobular/ovoid shape, and fluid cavities.
• MRI showed heterogeneous T2 hyperintensity, uniform contrast enhancement, a "salt-and-pepper" sign, and fluid cavities.
• Metastasis was confirmed in 13 dogs (lymph nodes, heart, bones); local invasion in 11.
• Pericardial/peritoneal effusions correlated with metastasis; vessel encirclement, mediastinal effusion, and right-sided congestive heart failure correlated with invasion.

Conclusions:

• CT and MRI provide valuable insights into canine aortic body paragangliomas, aiding in malignancy assessment.
• Specific imaging features like effusions and vessel encirclement can suggest malignancy, invasion, or metastasis.
• Malignant ABPs can invade locally and metastasize to distant sites, including bone, even in non-brachycephalic breeds.