Detection of pulmonary emboli in dogs using digital subtraction angiography

Digital subtraction angiography (DSA) was performed in six dogs to define the limits of detection of pulmonary emboli. Three angiograms were initially obtained in three normal control animals, two of which were subsequently embolized. A total of ten pulmonary angiograms were then obtained in five dogs that had experimentally produced emboli of Ivalon cubes (2, 3, and 10 mm). The intravenous angiograms were followed by selective arterial angiograms to confirm the presence and location of the emboli. The intravenous angiograms were independently reviewed by two radiologists. The criterion for detection was identification of a vessel cutoff. Perfusion defects were also seen. No intraluminal filling defects were seen. This study indicates that pulmonary emboli greater than 2 mm in diameter may be detected in dogs by DSA.