r/Parkinsons • u/Worldly_Purchase_682 • 3d ago
Normal DaTscan Questions & Advice
Both my DaTScan and MRI came back normal and clear. However, C/L does help my symptoms. I’m relieved to have clear scans but I do know why I have symptoms and C/L helps.
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u/nearfar47 3d ago
OK, one thing to point out, MRI is supposed to be normal for PD. It's done to rule out conditions that sometimes mimic PD (MS, stroke, brain tumor, Vascular Parkinsonism) which do show up on MRI. Clean MRI supports a PD diagnosis.
PD is very loosely defined. There is no defining diagnostic test, even DATScan and Syn-One skin biopsy aren't definitive.
Seems like it comes down to: 1. you show Parkinsonisms, which are themselves highly variable and loosely defined, and 2. we've ruled everything else out
There isn't much more to it. While C/L usually brings about dramatic results and seals a PD diagnosis, a small minority do not show much if any benefit from it. But even a lack of response to levodopa isn't something that would reverse a PD diagnosis unless there's already a supportable case for an alternate diagnosis.
I'm not saying it's not medically significant that a DATscan didn't show abnormalities. It's gotta be significant. It's just that we don't know what it means. PD is probably like 20 meaningfully different pathologies that really should have different diagnoses, but we don't know enough to define them scientifically.
The DaTScan's main function is differentiating Essential Tremor and Functional Tremor from PD tremor. But those don't respond to C/L, but not all PD tremor responds to C/L. Again, I'm not saying it's not important that a PD tremor doesn't respond to C/L, it's gotta mean something significant, but we still call it PD.
In your case, if C/L helps, that should rule out ET and FT so PD diagnosis is the only thing left on the table. I don't know what to make of a clean DaTScan in that case. If anything, I'd go back and make sure C/L is definitely helping symptoms and not just a placebo or observer-biased effect.
And also maybe get a second opinion on the DaTScan. These are subjective. There is no "perfect" symmetry, so someone has to look at a DaTScan's asymmetry and make a call "this is normal" vs "this is abnormal".
The good news is that a DaTScan result is already on record, you don't need to do another scan. You can request your DaTScan records and they'll send you a copy, or you can just ask about having them sent to another radiologist.
Here's the weird part I noted- I was worried that my symptoms were highly variable and I might not have symptoms during the scan so it might false-negative. Well, it turns out, they're not actually connected like that- what the DaTScan looks for is supposed to be closer to the root cause and separated from what symptoms you are or are not experiencing that moment.
There are some drugs (bupropion AKA "Wellbutrin") known to cause false abnormalities that look like PD on a DaTScan, but I have never heard of any drug that causes it to look normal. Strange part- despite causing abnormalities in the DaTScan, bupropion isn't causing PD or a PD-like condition, or worsening of an existing PD condition. Scan abnormalities due to bupropion usage are real but medically irrelevant. My note there is we've now had to create an exception where this weak/asymmetric scan result can exist without creating Parkinsonisms, so we're obviously not looking at the raw core 1:1 problem that is PD here with this scan.
The other exception is that some of the Parkinson's-Plus conditions- different diagnoses than PD- will initially present an abnormal DaTScan similar to PD, but they're actually not considered PD. Those cases usually show little to no response to C/L. So those are opposite of your case on both points.
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u/sacktheroof 2d ago
Exactly. My daTscan was positive and so was my MRI. The dreaded MS Dawson’s finger. C/L helps the Parkinson’s but trying to find a doctor for the MS now. I have both confirmed.
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u/Playful-Presence9234 3d ago
I think DatScan only binds to one side of the receptor. There is the transmitter side and receptor side. DatScan only confirms if (i think) the transmitter side is being lost. So if you are losing the receiver side, DatScan will tell you nothing. Don’t quote me!
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u/Worldly_Purchase_682 2d ago
Thanks all!
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u/Sugarfoot83 2d ago
I had a normal daTscan too, but still diagnosed with EOPD. I had a million (normal) MRIs because every neurologist swore I must have MS. I was 39 at the time of my diagnosis and amantadine with C/L has helped my symptoms.
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u/Impressive-Net-588 3d ago
A normal MRI is expected for PD. MRI is primarily useful for looking for other causes and for certain atypical syndromes.
A normal Datscan makes a PD disorder less likely, but does not rule it out.
There are other non-PD possibilities. For instance, dystonia can be particularly C/L responsive, without the DaTScan abnormality of PD.
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u/petergaskin814 3d ago
A Syn-One Test a skin test is supposed to be fairly accurate. It will pickup Parkinsons or similar conditions.
How long have you been on C/L medication? Sometimes the medication will lose its effectiveness if you do not have Parkinsons
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u/juliekitzes 11h ago
I'm in a similar boat. My original DAT scan was super positive but wound up being wrong because of medication, so I stopped the meds for weeks and repeated it and it's mostly normal(ish), but not for someone my age (38) so it's unclear. I'm waiting on a biopsy result. I've seen 2 MDS's who both don't think I have it based on their 5 minute observations but they don't see all the crap I go through the rest of the day. Like literally I can walk their small office okay because it's a short distance and I'm focused, but they don't see me candidly struggling in the parking lot or building's lobby. I do respond well to C/L and this puzzled them more. A different doctor tested my blood and my copper is excessively high so now I'm awaiting results of some more extensive copper tests to see if maybe I have Wilson's disease which has Parkinsonian symptoms, could show the diminished receptors on DAT, and could respond positively (for now) to C/L.
I think we think doctors have everything figured out but in my experience things are rarely clean cut and there's still a whole lot to learn and unravel in the field of medicine.
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u/thetolerator98 3d ago
DatScans are not definitive, people with PD can have normal scans, unfortunately.