Detecting a patent foramen ovale by transcranial doppler sonography (tcd)

In patients with cerebral ischemia of unknown origin, paradoxical embolism must be considered as one of the possible causes, if there is an abnormal right-to- left shunt. The most likely site of transmission is a persisting patent foramen ovale (PFO), which is found in approximately 30% of adult persons in autopsy studies. Using transcranial Doppler sonography (TCD) and an agitated saline solution as an inexpensive and readily available contrast medium, probably all clinically important right-to-left shunts can be detected. In our department we examined 215 patients within the last 5 years, 30% of which had an abnormal right-to-left shunt with insignificant difference between 10 and 69 years of age.