Saturday, October 16, 2010

CAAM, a clinical call for help from the echo engineers.

Accurate measurement of time intervals is critically important for successful Tau calculation. Garbage in, garbage out. But don't hesitate to move forward. We just need something like computer aided accurate measurement, CAAM. I figured out this word. :)

We are interogating the regurgitation by continuous wave Doppler. There are two different pieces of quartz crystals to emit the ultrasound and receive the echo separately. Theoretically, since there is no “waiting time” as needed in pulse wave Doppler, we can follow up every movement of the leaking RBCs, and the modern computer makes it possible to do the quick data processing. By that means, we can measure the two time intervals as accurate as we need.

On the other hand, the echo engineers can give us a pure curve instead of a “spectrum”. This pure curve is supposed to be a reasonably smoothed spectrum. Compared with regular spectrum, the curve is superior in consistancy, accuracy and automatic measurement.

So, the need to measure time intervals accurate is not doom of Tau calculation, it is boom of a fresh perspective in ultrasound. Just like in CT reading, there is a similar clinical call for CAAM.

This is the equation group used to calculate Tau in MR pt:

Tau = (t1-t2) / ln((16 + LAP -C) / (4 + LAP -C))
Tau = (t1-t3) / ln((36 + LAP -C) / (4 + LAP-C))

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