Cardiac-Gated CT Improves Detection, Staging, and Surgical Planning for Canine Right Auricular Masses

The Use of Cardiac-Gated Computed Tomography for Assessment of 12 Dogs With Suspected Right Auricular Appendage Masses: A Case Series

Josephine J. Gendler, Eric T. Hostnik, Hunter J. Piegols, Janis M. Lapsley, Laura E. Selmic

Background

Hemangiosarcoma is a highly metastatic malignant neoplasm and represents the second most common primary cardiac tumor site in dogs after the spleen. Accurate staging and assessment of tumor location are critical because surgical resection is most feasible when masses are confined to the right auricular appendage. Traditional staging methods include thoracic radiographs, abdominal ultrasound, and echocardiography, but these may have limited sensitivity or spatial resolution for cardiac tumors. Cardiac-gated computed tomography (CT), which synchronizes image acquisition with the cardiac cycle to reduce motion artifacts, may improve visualization of cardiac masses and their relationship to surrounding structures. This study aimed to describe the use of cardiac-gated CT for determining tumor location, extent, and metastatic staging in dogs with suspected right auricular appendage masses.

Methods

This retrospective case series reviewed cardiac-gated CT reports from 12 dogs evaluated between 2018 and 2023 at a veterinary medical center for suspected right auricular appendage masses. Imaging reports from thoracic radiographs, echocardiography, CT scans, and abdominal ultrasound were assessed for mass detection, location, and evidence of metastases. Surgical and necropsy reports were reviewed when available to confirm tumor location and outcomes. Descriptive statistics were used to summarize signalment, imaging findings, and survival times.

Results

Cardiac-gated CT identified a cardiac mass confined to the right auricular appendage in seven dogs and involvement of additional cardiac structures in five dogs. Echocardiography detected or suspected cardiac masses in seven of nine dogs examined but frequently disagreed with CT regarding precise mass location. Metastases were suspected on CT in 10 dogs (83%), commonly affecting the liver, spleen, lungs, lymph nodes, and occasionally muscle or peritoneum. Five dogs underwent thoracotomy with intent to remove the mass; right auriculectomy was successfully performed in four dogs. One dog with suspected atrial involvement died intraoperatively during attempted resection. Median survival time was 174 days for dogs that underwent surgery compared with 14 days for dogs that did not.

Limitations

The study had a small sample size and limited histopathologic confirmation in some cases. Additionally, not all dogs underwent surgery or necropsy, which limited definitive verification of tumor location and extent. Retrospective design and reliance on imaging and procedural reports also introduced potential variability in data quality.

Conclusions

Cardiac-gated CT provided valuable information for evaluating suspected right auricular appendage masses in dogs, particularly for determining tumor location, extent, and surgical feasibility. The modality also functioned as a sensitive staging tool for detecting suspected metastases. These findings suggest cardiac-gated CT can improve clinical decision-making for dogs with suspected cardiac hemangiosarcoma, although further studies comparing it with other imaging modalities are warranted.

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