Differentiation of dementia with Lewy bodies from Alzheimer's disease using a dopaminergic presynaptic ligand.
BACKGROUND
Dementia with Lewy bodies (DLB) is one of the main differential diagnoses of Alzheimer's disease (AD). Key pathological features of patients with DLB are not only the presence of cerebral cortical neuronal loss, with Lewy bodies in surviving neurones, but also loss of nigrostriatal dopaminergic neurones, similar to that of Parkinson's disease (PD). In DLB there is 40-70% loss of striatal dopamine.


OBJECTIVE
To determine if detection of this dopaminergic degeneration can help to distinguish DLB from AD during life.


METHODS
The integrity of the nigrostriatal metabolism in 27 patients with DLB, 17 with AD, 19 drug naive patients with PD, and 16 controls was assessed using a dopaminergic presynaptic ligand, (123)I-labelled 2beta-carbomethoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl)nortropane (FP-CIT), and single photon emission tomography (SPET). A SPET scan was carried out with a single slice, brain dedicated tomograph (SME 810) 3.5 hours after intravenous injection of 185 MBq FP-CIT. With occipital cortex used as a radioactivity uptake reference, ratios for the caudate nucleus and the anterior and posterior putamen of both hemispheres were calculated. All scans were also rated by a simple visual method.


RESULTS
Both DLB and PD patients had significantly lower uptake of radioactivity than patients with AD (p<0.001) and controls (p<0.001) in the caudate nucleus and the anterior and posterior putamen.


CONCLUSIONS
FP-CIT SPET provides a means of distinguishing DLB from AD during life.
University College London, UK. z.walker@ucl.ac.uk
Z
Z
Walker
D C
DC
Costa
R W H
RW
Walker
K
K
Shaw
S
S
Gacinovic
T
T
Stevens
G
G
Livingston
P
P
Ince
I G
IG
McKeith
C L E
CL
Katona
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000523:psychology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D020961:Lewy Body Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000523:psychology; D008297:Male; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology; D011954:Receptors, Dopamine / Q000502:physiology; D017661:Receptors, Presynaptic / Q000502:physiology; D012680:Sensitivity and Specificity; D013378:Substantia Nigra / Q000000981:diagnostic imaging / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
D007457:Iodine Radioisotopes; D011954:Receptors, Dopamine; D017661:Receptors, Presynaptic; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane