Transcranial Doppler (TCD) is a new, non-invasive way to diagnose a PFO. It is extremely accurate, pain-free, and takes about 15 minutes.
A small ultrasound probe is placed on the temple just above the ear. Ultrasound waves locate the flow of blood in the arteries of the head (see figure 1)
An intravenous is placed in the arm and a saline solution (sterile salt water) is injected. The saline solution is filled with tiny dissolved microbubbles.
If there is no PFO, all the microbubbles are filtered by the lungs and no change is seen in the tracing of the blood flow.
If there is a PFO, some of the microbubbles pass (unfiltered by the lungs) through the PFO and travel to the arteries in the head. The ultrasound waves are strongly reflected by even the smallest bubbles and are detected by the probe. They are displayed as sharp color lines on the tracing (see figure 2).
The injection is repeated while the patient takes a deep breath and then exhales forcefully as these maneuvers may be required to "open" the PFO.
The results of the test are available immediately and are discussed with the patient before he/she goes home. A copy of the results are forwarded to the primary care physician the same day.
The risk of this test is negligible. There is no risk in injecting this microbubble saline solution as the "bubbles" are microscopic and completely dissolved in solution.
To arrange PFO screening using Transcranial Doppler (TCD) contact us.