The utility of continuous high-enhanced-contrast electrocardiography-gated cardiac computed tomography method evaluating accurate minimal ductal diameter and ductus arteriosus morphology in a dog with patent ductus arteriosus.

A three-year-old, 4.1-kg, female Shih tzu was referred for investigation of exercise intolerance and heart murmurs. At the first visit, the dog was diagnosed with patent ductus arteriosus and a suspected persistent left cranial vena cava using echocardiography. Electrocardiography (ECG)-gated non-helical, stationary 320-slice multidetector cardiac computed tomography (CCT) was performed to classify the morphology and to measure the minimal ductal diameter. However, the ductal ostium at the pulmonary artery was not clearly visualized. To overcome this problem, we developed the continuous high-enhanced-contrast ECG-gated CCT method and performed it before catheter intervention. This method is characterized by performing CCT continuously with retrospective ECG-gated scans initiated almost simultaneously with contrast medium administration. We were able to obtain reconstructed images, confirming there was no contrast in the aorta, while the pulmonary artery remained well opacified, which led to the accurate evaluation of minimal ductal diameter and ductus arteriosus morphology.