[pegleg]

Finally, we're getting somewhere!
Peg

PET IMAGING UPS DIAGNOSTIC ACCURACY IN PARKINSON'S
Headline of article by Nancy Walsh, Contributing Writer, MedPage Today
Published: January 11, 2010

Metabolic brain imaging improved diagnostic accuracy by about 20% in patients with features of early parkinsonism but an uncertain clinical diagnosis, international researchers reported.

Writing online in Lancet Neurology, Chris Tang, MD, of the Feinstein Institute for Medical Research in Manhasset, N.Y., and colleagues reported that image-based classification for idiopathic Parkinson's disease had 84% sensitivity, 97% specificity, 98% positive predictive value, and 82% negative predictive value.

The article goes on to say:
"Neuroprotective and disease-modifying drug research is intensifying and results mostly rely on accurate early diagnosis. If neuronal loss in Parkinson's disease follows a linear or exponential pattern, early treatment is crucial," Antonini argued.
But advanced imaging should not be considered a replacement for thorough clinical investigation by movement disorder neurologists, and prospective multicenter studies are needed to confirm the accuracy of this metabolic pattern-based approach, he cautioned.

http://www.medpagetoday.com/Neurology/ParkinsonsDisease/17875

[pegleg]

Thanks for your thanks, Jean! lol

I am bumping this up because I don't think enough of you read this, nor did you realize the significance (or inference) made with this discovery. Maybe I chose the wrong excerpts from the article, so I will try again.

Basically, it says: that a new brain imaging technique can help differentiate Parkinson's disease from other neurodegenerative disorders early in the course of disease, when treatment may be most beneficial
The article says: " . . . published clinicopathologic data suggest that the positive predictive value of a clinical diagnosis, even by a specialist, is only about 75%."

Although the PET imaging is following how most patieints are diagnoseod with PD - by still proving what PD is not - this could have great ramification on research studies -quoting again:
" Many neurodegenerative diseases share common signs and symptoms, and some 80% of patients misdiagnosed as having Parkinson's disease actually have multiple system atrophy or progressive supranuclear palsy.


These conditions have a much worse prognosis than idiopathic Parkinson's disease, which does not substantially shorten lifespan.
Moreover, treatments differ for these conditions, so more accurate diagnostic techniques have been needed."

If this PET scan can help reduce that 80% misdiagnosed, then that's a whaleofa discovery!

By the way, this came out of the Feinstein Institute, who recently gave us the information on the longitudinal improvement of participants in the fetal tissue trials.

And here's another reason that this new information is significant:

They also calculated these discriminative values for patients with short duration of disease (less than two years), when it can be particularly difficult to make a diagnosis clinically because disease-specific features have not yet appeared.

Patients with short duration of disease also would be "ideal participants in clinical trials of potential disease-modifying drugs," the investigators noted.

Among 55 patients with short-duration disease, the positive predictive values for idiopathic Parkinson's disease and atypical parkinsonian syndrome were 92% and 95%, respectively.

And among 33 of these patients who were then followed for at least two years after imaging, the positive predictive values rose to 94% and 100%.
This ability to make an imaging classification accurately several years before the final clinical diagnosis "is especially relevant when considering treatment options for patients with medically refractory parkinsonism because invasive surgical approaches such as deep brain stimulation are generally ineffective for patients with atypical parkinsonian syndrome," the investigators wrote.

Primary source: Lancet Neurology
Source reference:
Tang C, et al "Differential diagnosis of parkinsonism: a metabolic imaging study using pattern analysis" Lancet Neurol 2010; DOI: 10.1016/S1474-4422(10)70002-8.

Additional source: Lancet Neurology
Source reference:
Antonini A "Imaging for early differential diagnosis of parkinsonism" Lancet Neurol 2010; DOI: 10.1016/S1474-4422(09)70360-6.

[RLSmi]

Peg,
PET scans are quite expensive. Given the choice between obtaining a Dx by trying Sinemet or a DA, and having a PET performed, I fear that the choice of whoever is paying for it would fall on the side of the least expensive approach.
If left up to a pharma looking for true early PD clinical trial subjects, use of PET would provide a nice excuse for escalating the price of a resulting "designer" neuroprotective drug.
Robert

[pegleg]

I hope you understand that I am not being rude to you, but this really bothers me.

I knew that cost had to be factored into this, but do you know of any other disorder, disease or syndrome where the "proof is in the pudding" is to administer a chemical that could alter an entire bbody system? And this system just happens to be one that regulates all other body systems? I really think the neurology doctors and orgs frown on this antiquated practice, just as "drug holidays" are no longer acceptable.

And while I am on my soapbox, what do you think about drilling through one's skull for either treatment or experimentation without the etiology confirmed? (and sham surgery? Don't even go there.)

Do you think that an orthopedic doctor would even pick up his/her scapula to operate on a patient's back if a herniated disc had not been confirmed via an MRI or scan? (Hint: the answer is NO!)

I would love to hear some comments about the issue or biomarkers (or the lack of) for Parkinson's.

[jeanb]

I have been in an ongoing clinical trial for SPECT scans with BETA-CIT since 2003!! I found the following info -- and I do not understand why SPECT and/or PET are not used as diagnostic tools for Parkinson's.

"CONCLUSION: FP-CIT SPECT and F-DOPA PET scans are both able to diagnose presynaptic dopaminergic deficits in early phases of PD with excellent sensitivity and specificity."

http://www.ncbi.nlm.nih.gov/pubmed/19037637

jean

[RLSmi]

and I should have known better, Peg. I apologize and promise to be more positive in my posts.
Jean, I have gone through the CIT-SPECT process along with my sister and two neices once at IND in New Haven in 2006 right before the World Parkinsons Congress. We were referred to them by the folks at PROGENI in Indianapolis. We all found it to be an interesting experience, and the VIP treatment they give participants was enjoyable. They apparently are not following up on the familial PD project of which we were a part. My mother and older brother also had PD.
Robert

[pegleg]

Robert - you were just beingn "practical" not "cynical."

Jean you said: "I do not understand why SPECT and/or PET are not used as diagnostic tools for Parkinson's."

I think there are two answers (or reasons)
(in my opinion)
1) They are still testing them, as is indicated to your present trial participation.

2) The Almighty dollar once again rules .

I think that we should be scared to death (gulp!) about the U.S. Health reform. Are we going to let the "cost" of science determine who lives or dies or what quality of life one should have? Does the "label" Parkinson's constitute an attitude of apathy for care because there's no known cure or etiology?

I don't think our orgs or the Fox Foundation will let this happen. We should be behind a media blitz to say "Don't forget us!"
Peg

[jeanb]

Peg,

What i meant to say is why haven't they applied for FDA approval to use SPECT as diagnostic tool yet?! They have been following approx. 500 pwp starting when we were "de novo" patients in 2001-2003 and then more scans every other year through 2009 (so far and more to come) ! That is a lot of scans and a lot of data.

[Fiona]

I just want to say, European friends and others worldwide, ins't it standard practice in your countries to at least get a DAT scan before confirming a diagnosis?

I agree with you, Peg, that given the severity of the possible condition and the significance of the outcome, one would think they would try to be a little more scientific if the tools are out there....

But the thing about we have to diagnose it as soon as possible - when I was diagnosed they wanted to postpone the meds as long as they felt right because of the thinking that they would stop working sooner if started sooner. And I don't know what PD drug has been proven to be neuroprotective. The Azilect ADAGIO study? Wasn't that basically discredited a while ago. In fact even my doctor told me that the agonists can "hasten or worsen the disease."

[aftermathman]

as my Neuro believes it is cost effective regarding the cost of drugs (especially dopamine agonists) versus a mis-diagnosis.

Also as I am a YOPD (dx at 40), he felt that insurance companies would insist on a scan to support the dx.

Strange what is happening "over the pond" in this regard.

Neil.