The contribution of statistical parametric mapping in the assessment of precuneal and medial temporal lobe perfusion by 99mTc-HMPAO SPECT in mild Alzheimer's and Lewy body dementia.
OBJECTIVE
To assess the role of 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (99mTc-HMPAO SPECT) imaging of the precuneus and medial temporal lobe in the individual patient with mild Alzheimer's disease and dementia with Lewy bodies (DLB) using statistical parametric mapping and visual image interpretation.


METHODS
Thirty-four patients with mild late-onset Alzheimer's disease, 20 patients with early-onset Alzheimer's disease, 15 patients with DLB and 31 healthy controls were studied. All patients fulfilled appropriate clinical criteria; the DLB patients also had evidence of dopaminergic presynaptic terminal loss on 123I-N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl)-tropane imaging. 99mTc-HMPAO SPECT brain scans were acquired on a multidetector gamma camera and images were assessed separately by visual interpretation and with SPM99.


RESULTS
Statistical parametric maps were significantly more accurate than visual image interpretation in all disease categories. In patients with mild late-onset Alzheimer's disease, statistical parametric mapping demonstrated significant hypoperfusion to the precuneus in 59% and to the medial temporal lobe in 53%. Seventy-six per cent of these patients had a defect in either location. No controls had precuneal or medial temporal lobe hypoperfusion (specificity, 100%). Statistical parametric mapping also demonstrated 73% of patients with DLB to have precuneal abnormalities, but only 6% had medial temporal lobe involvement.


CONCLUSIONS
These findings illustrate the capability of statistical parametric mapping to demonstrate reliable abnormalities in the majority, but not all, patients with either mild Alzheimer's disease or DLB. Precuneal hypoperfusion is not specific to Alzheimer's disease and is equally likely to be found in DLB. In this study, medial temporal hypoperfusion was significantly more common in Alzheimer's disease than in DLB. Statistical parametric maps appear to be considerably more reliable than simple visual interpretation of 99mTc-HMPAO images for these regions.
Kemp
Paul M
PM
Department of Nuclear Medicine, Southampton University Hospitals Trust, Southampton, UK. paul.kemp@suht.swest.nhs.uk
Hoffmann
Sandra A
SA
Holmes
Clive
C
Bolt
Livia
L
Ward
Tony
T
Holmes
Robin B
RB
Fleming
John S
JS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000033:anatomy & histology; D019295:Computational Biology; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D020961:Lewy Body Disease / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010477:Perfusion; D012984:Software; D019690:Technetium Tc 99m Exametazime / Q000494:pharmacology*; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes
D007457:Iodine Radioisotopes; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D019690:Technetium Tc 99m Exametazime