now you see it now you don't!!

thanks for your reply but would just like to ask the following questions to clear things up a bit:

1.  Is it possible to see clear shunting on a bubble echo and then an MRI determine no ASD's or shunt?

Hence... Do bubble echo's sometimes produce false positives?

3. would you use a normal MRI or contrast enhanced MRI to detect a shunt?

4. Can a normal MRI (non contrast) produce false negatives in ASD detection?

Thank you I apppreciate your time.

[Douglas Bogart, MD]

You can have a PFO which is demonstrated on the echo but the MRI tests for damage to the brain ie, it checks for small strokes.  Since about one in four people have a PFO and PFO's are a rare cause of strokes it is very plausible to have a PFO with no evidence of a stroke.  I think the confusion here is that the 2 tests MRI and echo look at different things.