Scan-dal?

Rich66 · 09-07-2010, 08:36 AM

Anyone had a PET/CT that refers to previous measurements but when you look at the previous report, the measurements are different? The report doesn't seem to mention "correcting" erroneus measurements, so...shouldn't they be quoting what was in in the previous report?
This has happened with the last two PET/CTs. The discrepancies aren't large, but possibly enough to influence the judgement of how large a progression and how to proceed.

chrisy · 09-07-2010, 08:50 AM

I've not noticed that specifically, but I have frequently seen use of the word "approximate" in measuring size - remember we are talking about irregularly shaped things and the pictures are not always super distinct, even to the trained eye. So there is art and skill required to read the scans.

Rather than just quote the prior report, the radiologist would be looking at and comparing the actual scans, current and previous so that could explain it.

If you are seeing larger discrepancies, or feel there is a treatment decision that will be affected, I would ask them to reread and verify.

Rich66 · 09-07-2010, 10:31 PM

Was told today that it is a disturbingly common artifact of the state of the art. Next scan, hiring an Amish carpenter to measure.

chrisy · 09-08-2010, 02:35 PM

There's a difference between measurements changing between scans and the reading of different measurements on the same scan. The latter is all reader based. The former could be either the reader or the size actually changed or nothing changed and the scan "slice" picked up a slightly different piece to measure. none of these really bother me if it's not a significant change. Only if it could impact treatment decisions, then I would double and triple check

Rich66 · 09-08-2010, 02:47 PM

Things can change between scans. That's why they're done.
I'm still a little unclear why measuring would be an art. If I'm measuring something irregular, the logical thing is to measure the furthest lengths. If you're going to report it on an X/Y, 2 dimensional axis, draw a box around it. Done. Or use a more complex method like tracing the perimeter and generating a number from that. Whatever the method, settle on it...and make an iPhone app of it.

chrisy · 09-08-2010, 07:44 PM

You've seen actual scans, right?

I've seen many, my experience is that they are more like UFO pictures than 40 pixel digital photos. I agree they need am app to get clear, unambiguous pictures.

I think they had it in star trek but it was called a medical tricorder