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123-I ß-CIT (Dopascan)
Cocaine 123-I ß-CIT
• 123-Iodine ß-CIT is a phenyltropane analog of cocaineradiopharmaceutical for imaging dopamine transporters in brain
123-I FP-CIT
123-I ß-CIT State and Trait Biomarker for PD
Nigral Dopamine loss -
Face validity
(> 4000 scans in > 30 clinical imaging studies)
Reduction in early PD
50% Put
Reduction Put>Caud
Yes
Reduction asymmetric
Yes
Correlation with severity
Yes
(UPDRS)
Reduction in Pre-diagnostic Yes
Monitor PD progression
Yes
Time
Neu
ron
Func
tion
Clin
ical
Rat
ings
Pre-diagnostic
Symptomatic
Diagnosis
Natural History of PD No Treatment
Symptom Threshold
50-60% loss of contra put
DAT Imaging for diagnosis of Parkinson syndrome: Suspects and SWEDD
• Patients with Suspected PS -
can DAT imaging improve diagnostic accuracy?
• Subjects enrolled in clinical trials with Scans without evidence of dopaminergic deficit (SWEDD) –
can DAT imaging
identify subjects who do not have PS.
Unsure about a Parkinsonian diagnosis??
Consider a referral to the Query-PD study and participate in the development of a diagnostic tool for PD
Methods• Patients with suspected PS, referred by
community neurologists for imaging.• Referring neurologist provided:
– ‘best guess’ diagnosis– Certainty of diagnosis – Info regarding specific PD symptoms (rest
tremor, bradykinesia, rigidity, etc)– Response to dopaminergic medications
• Baseline: MDE examination• Baseline: [123I]β-CIT/SPECT
– Visual and quantitative outcome compared with healthy database (n=100)
• 3 month f/u: clinical dx (blind to imaging data) • 12 month f/u: clinical dx (blind to imaging data)
determined ‘Gold standard’ diagnosis
Demographics/Baseline Data
Community Neurologists (n=37)Patients enrolled (n=137) Patients completing final clinical visit (n=131)
Age 62.3 yrs (range 30-92)Gender 54% male, 46% femaleSx duration 2.1 yrs
Baseline imaging and clinical assessment of this population of suspected PS compared to independent MDE 12 mo dx -
‘Gold Standard’
Final Clinical Diagnosis PS No PS Sensitivity SpecificityArea under the curve
Enolling MDE baselinePS 57 32 0.97 0.55 0.76
No PS 2 39Independent MDE baseline
PS 45 9 0.76 0.88 0.82No PS 14 63
Quantitative ImagingPS 52 8 0.88 0.89 0.89
No PS 7 64
Referral neurologist identified population of suspected PS36 neurologist referred 137 subjects
59 (43 %) PS, 68 (57%)not PSBased on independent MDE 12 mo dx -
‘Gold Standard’
QUERY-PS STUDY
SWEDD (Scans Without Evidence of Dopaminergic Deficit) in PD Trials
Study
Stage –PD
Dur DX at
% SWEDD
Baseline(mo)
Elldopa-CIT Denovo
6
21/142 (14%)
PRECEPT
Denovo
8
91/799 (12%)
REAL-PET
Denovo
9
21/186 (11%)
Calm-CIT
Start of 18 3/82 (4%)DA Rx
GPI1485
Treated
23
3/212 (1.4%)
Stable responder
PRECEPT study - FOLLOWUP IMAGING AND CLINICAL OUTCOMES BY SWEDD STATUS
AT BASELINE
Mean (SD) for Change in [123I] ß-CIT and UPDRS, Percent (CI) for need for DA treatment. * indicates p < 0.01
DAT imaging in diagnosis of PS
•
Need for additional diagnostic tools for community neurologists for difficult to diagnose subjects with suspected PS –
DAT imaging is a
useful tool for these patients.
•
DAT imaging can identify subjects without PS even among subjects enrolled into PD clinical trials –
DAT imaging is a useful tool to identify patients who do not have PS.