The mayo clinic just found papvr/chd. after 25 years of missing it from all my other doctors. is it possible for us to get a false positive? it was found during a ct scan using 2 contrast oral/vien? ?

See answer : Partial anomalous venous connection may be diagnosed at any time from birth to old age. Severity of symptoms, and thus the likelihood of diagnosis, varies significantly depending on the amount of blood flow through the anomalous connections. In less severe cases, with smaller amounts of blood flow, diagnosis may be delayed until adulthood. Rx: medical, interventional cardiac cath, or open surgery.

Very Rare False +: A false positive test would be very rare as the doctor making this diagnosis from the ct scan should have clearly seen a pulmonary vein carrying blood from the lungs to the "wrong" place in the heart.

PAPVR: Partial anomalous pulmonary venous return is not easy to diagnose at all. Most tests other than what you had would be likely not to image it. It being 'missed' for 25years is more usual than unusual.