I'm a bit surprised to be reading on the internet about how many people "with PD" have had the DaTscan and it shows things are normal upstairs. People with long-standing tremor, cogwheel rigidity, no arm swing, etc., and many of the ones I've read about are YOUNG! How can people have classic PD symptoms, whatever those really are, and yet their DaTscan shows no degeneration?

Am I missing something? Does taking PD drugs mask things so that an otherwise degenerated substantia nigra appears normal on the scan?

I was thinking this scan could be so very useful, but if as many PWP as I'm reading about are having "normal" DaTscanrs of their brains, what does this tell us? I feel like these results are showing us just how flawed the thinking about PD has been for many decades. Wrong?

And getting to the core: what if you had a DaTscan, and it showed things were normal, like Harley...what would you do? You still have tremor, rigidity, etc., but now the scan would be saying, hey, nothing out of the ordinary here! Do you stop taking your PD drugs? But you still have symptoms! What could/would a doctor do at that point?

accidentally deleted better post, apologies for scrappy post below.....

my neuro continued to treat me, asked me whether sinemet helped, I said yes. it still does. his colleagues were not interested in me, only in looking at scan results. he looked at me and calls it PD..........

recent posts about dopa-responsive parkinsonism might be part of the answer

my datscan experience; went in, had injection, plus a liquid iodine preparation, got there well in time as I was told it was time sensitive. scan was done about half hour late, took 40 mins and my head was held in some kind of plastic restraint, was sent home. scan done by two technicians. results should have come in 2 weeks, only got them after 2 months and some pressure on hospital. would love to know what it was like for others.

some thoughts; don't know if this is true, was told that a prior MRI is needed, as the target is so small. unless it was all done in that session I have not had one done.

when results are processed there is digital enhancement, can this be a cause for false negatives, or indeed false positives. it would help patients if they understood exactly what this process is, how the results are arrived at. have looked for this information, if anyone knows, I would be interested....

is ANYTHING 100% accurate?

is parkinson a spectrum as most of us seem to believe - then why would there not be brain differences, and differing results......

maybe this scan is not everything it is said to be. other things are painted in rosy colours, but we know that there are downsides, is this the same?

my neuro said 6% false negatives, are there also false positive, scan failures, other anomalies? is there postmortem data that backs up accuracy, there hardly seems time for that.

in the uk datscan is often used only when there is a question mark over diagnosis. cost dictates this. but some areas nearly everyone seems to be scanned. how might this affect data?

do people mostly have datscan prior to going on medication? I had been on ldopa for 2-3 years. Harley for a very long time. does this affect results?

do doctors keep data on this, do the datscan people...........? or is it just seen
as a given that a negative definitively means no Pd....... do all doctors look at the scan, or do they look at the results? i have never seen mine, did the neuro who ordered it see it? hard to know......

i guess we all have questions that keep hunting in our minds, especially those of us who haven't a proper name for what we are living with.....

Lindy,

I posted previously on the question of interpretation of scans:

http://neurotalk.psychcentral.com/thread149034.html

Also, with reference in particular to spect scans, i was told that if you have several of them, they really need to be done on the same machine, same protocol and same person reading the scan, to have any real validity of comparison.

And on a not so minor point - I was once given someone else's MRI to take away from the clinic to my neurologist. Luckily i checked the name on the side of the film myself.

Thanks for reminding me and for posting the link originally, Muirann. This is exactly what I was referring to. It's a long but very informative video. It doesn't explain everything we need to know, but gives an idea of the 'photoshop-ing' stuff...... Muirann's comment with her original post is also illuminating....

The experience with the mixed up scan shows exactly how human error can creep in, the more removed the process the more likely it could happen, more chance of error creeping in, either way.

Lindy,

To add fuel to the fire of human error - the neurologist who ordered the first DaTScan didn't actually see the film himself, only the report. The second neurologist I attended, proceeded to instruct a student on my case, with the film facing wrong way around so he claimed all my sx's were on the wrong side. He then 'lost' my second DaTScan, though I did get to view it once before this occurred. No apologies either for any of this, only dog's abuse when I brought it to their attention.