when a patient develops swelling in the same arm as a PICC. what is the best method for finding the cause. I understand that an ultrasound can be done to look for a CADVT. I have seen them results that state "Hypoechotic" area or mass noted. My question is what differentiates the PICC from a clot, or is that even possible. My question is based on a patient that had marked swelling in the arm with a picc. The dopplar ultrasound was done and stated the above up that extended into the subclavian. The pt was started on lovenox and the md wanted the picc removed the next day. 18 hours after picc removal pt developed SOB HTN desaturation. due to elevated creat no spiral ct available for r/o PE. Follow up ultrasound done to arm showed no obstructions at all. So the question is was the picc the Hypo echotic structure or did the clot dissolve that quickly?