Do you routinely repeat imaging for PE after anticoagulation treatment to establish a new baseline?

We only do imaging if the patient is symptomatic still after a few weeks or has persistent chest pain or clinical signs of pulmonary hypertension. Rarely I have seen recurrent or progressive thromboembolic disease on anticoagulation.

No. A CT angio is a very expensive test in comparison to Dopplers of the lower extremities. I also find that I do not struggle as much with decision-making surrounding "new" versus "old" clot in the evaluation of a recurrent pulmonary embolism in the same way that I struggle with "new" versus "old" ...