Dopamine transporter loss visualized with FP-CIT SPECT in the differential diagnosis of dementia with Lewy bodies.
BACKGROUND
Dementia with Lewy bodies (DLB) is a common form of late-life dementia that can be difficult to differentiate from other disorders, especially Alzheimer disease (AD), during life. At autopsy the striatal dopaminergic transporter is reduced.


OBJECTIVE
To examine the extent and pattern of dopamine transporter loss using iodine I 123-radiolabeled 2beta-carbomethoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FP-CIT) with single-photon emission computed tomography (SPECT) in DLBs compared with other dementias and to assess its potential to enhance a differential diagnosis.


METHODS
Cohort study comparing FP-CIT with criterion standard of consensus clinical diagnosis.


METHODS
General hospital.


METHODS
One hundred sixty-four older subjects (33 healthy older control subjects, 34 with NINCDS/ADRDA [National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association]-confirmed AD, 23 with consensus guideline-confirmed DLB, 38 with United Kingdom's Parkinson Disease Society Brain Bank-confirmed Parkinson disease [PD], and 36 with PD and dementia).


METHODS
Injection of (123)I-2beta-carbomethoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl) nortropane with SPECT scan performed at 4 hours.


METHODS
Visual ratings of scans and region of interest analysis.


RESULTS
Significant reductions (P<.001) in FP-CIT binding occurred in the caudate and anterior and posterior putamens in subjects with DLB compared with subjects with AD and controls. Transporter loss in DLBs was of similar magnitude to that seen in PD, but with a flatter rostrocaudal (caudate-putamen) gradient (P =.001), while the greatest loss in all 3 areas was seen in those who had PD and dementia. Both region of interest analysis and visual ratings provided good separation between DLBs and AD (region of interest: sensitivity, 78%; specificity, 94%; positive predictive value, 90%) but not among subjects with DLB, PD, and PD with dementia.


CONCLUSIONS
Dopamine transporter loss can be detected in vivo using FP-CIT SPECT in DLB. Further studies, especially of subjects with DLB without PD, are required to fully establish use in clinical practice.
O'Brien
John T
JT
Institute for Ageing and Health, Newcastle University, Wolfson Research Centre, Newcastle General Hospital, Newcastle upon Tyne, England. j.t.o'brien@ncl.ac.uk
Colloby
Sean
S
Fenwick
John
J
Williams
E David
ED
Firbank
Michael
M
Burn
David
D
Aarsland
Dag
D
McKeith
Ian G
IG
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000378:metabolism; D015331:Cohort Studies; D003937:Diagnosis, Differential; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis* / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010300:Parkinson Disease / Q000175:diagnosis / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes
D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane