Dynamic Volume CT

[icestac]

I'm not a doctor, but I did stay at a Holiday Inn Express.

I recently heard an ad about a Dynamic Volume CT. They talk about how it gives a 3D image of the heart and stuff. They're offering the scan for $125. I was curious if there was any chance it could detect a PFO. If it could, I think that is a very reasonable price to find out.

http://medical.toshiba.com/products/...t-coverage.php

Like I said, I'm no doctor so please let me know if this is a stupid question.

Cheers,
Jeff

[karst.window]

The bottom line is that TEE with a bubble study is still the "gold standard" for PFO detection. Cardiac MRI and Dynamic CT are relatively new technologies that are able to detect PFO's with reasonable sensitivity and specificity. CAUTION: Be careful with undergoing diagnostic tests when you have no symptoms. Many times these tests which seem harmless can lead to findings that warrant further work-up and further risk as they are usually more invasive. If you have had symptoms in the past that indicate that some type of work-up should be performed then it would be reasonable to undergo the test as it is less invasive than a TEE which will require sedation and possible general anesthesia. However, at present time... if I needed a work-up for a possible PFO then I would likely opt for the more definitive test and go for the TEE and bubble study. Again, if you have no symptoms that would indicate a PFO then I caution you to obtain a CT out of "curiosity" regardless of the cost as it could lead to further studies that are more invasive and possibly unnecessary.

Sean

[icestac]

Thanks Sean.

Just out of curiosity, let's say you did have symptoms of a PFO. You said that you would opt for a TEE first even though it is more invasive. If the Dynamic Volume CT could detect it, why wouldn't you go there first? If it is positive, then you know and you've avoided a more invasive procedure. If it is negative, then you're out $125 and you go for a TEE.

Now I could understand that a lot probably has to do with the person administering the test. For this example, lets assume they are competent and feel reasonably confident that they could detect the PFO with the Dynamic Volume CT.

Just wanting to understand the logic.

Cheers,
Jeff

[kwayne88]

The bottom line is that TEE with a bubble study is still the "gold standard" for PFO detection. Cardiac MRI and Dynamic CT are relatively new technologies that are able to detect PFO's with reasonable sensitivity and specificity. CAUTION: Be careful with undergoing diagnostic tests when you have no symptoms. Many times these tests which seem harmless can lead to findings that warrant further work-up and further risk as they are usually more invasive. If you have had symptoms in the past that indicate that some type of work-up should be performed then it would be reasonable to undergo the test as it is less invasive than a TEE which will require sedation and possible general anesthesia. However, at present time... if I needed a work-up for a possible PFO then I would likely opt for the more definitive test and go for the TEE and bubble study. Again, if you have no symptoms that would indicate a PFO then I caution you to obtain a CT out of "curiosity" regardless of the cost as it could lead to further studies that are more invasive and possibly unnecessary.

Sean

I have a question that maybe can be answered. I can’t recall ever having any of the symptoms of PFO I have read about. I have also made a few dives to 300 ft and several in the 220 to 260 range without any problems such as skin bends or such.

I can’t find it now but I am sure I have read about a couple people not having symptoms but having a major hit after a deep dive that was later found out to be caused by PFO. If I have no symptoms and want to continue to do deep dives, wouldn’t a test be wise?

[karst.window]

I would absolutely have the TEE over the CT if I was looking for a PFO in the setting of having a high probability of having a PFO. Currently CT is not going to have the level of sensitivity/specificity I would like if I have to know AND I have a reasonable chance(higher than the general population 20-30%) of having a PFO (i.e. I have had stroke symptoms or "unearned DCS).

A fair number of divers to have PFO's yet they don't get bent. So just the mere presence of a PFO doesn't indicate that you will get bent necessarily. It means your chances may be higher.

If you find that you do have a PFO yet you have never been bent in your life are you going to get a closure device placed? Personally, I would not. You might choose to be more conservative, possibly not do deep dives, or possibly not dive at all. Those are all personal decisions.

Unfortunately at this time there just isn't sufficient data out there for anyone to make a recommendation to divers who have PFO's.

It is bound to be EVEN more complicated by the mere fact that not all PFO's are created equally. Some people with PFO's shunt little to no blood across from Right to Left. Some however have larger PFO's and shunt a significant amount of blood across from the right to the left side of circulation. So just the presence of a PFO doesn't indicate anything. You need to know how large it is and is it shunting right to left. Then again if it is shunting right to left is that going to cause the bends? None of these questions have yet to be answered.

So there is a lot of work that needs to be done in this regard. Sorry to be so enigmatic and cryptic but unfortunately the short answer is that there is not answer yet.

Sorry,

Sean