May do Angiogram if clinical picture complicated. An low probability scan can be used to withhold treatment, but if clinical signs are compelling then Angiogram is indicated. An intermediate probability scan provides no information and an angiogram is needed in further evaluation. A catheter in the pulmonary artery injects X-ray dye to outline the pulmonary artery. No defects are present and hence no pulmonary emboli.
Pulmonary angiograms show lobulated defects in the dye column filling the pulmonary arteries.
This proves the diagnosis of pulmonary embolism. During angiography, a catheter passes the right heart and may induce arrhythmia. This is more significant in Left Bundle Branch Block cases. X-ray contrast injection causes some increase in pulmonary resistance. Rarely a catheter may knot or perforate the heart.