Memory-provoked rCBF-SPECT as a diagnostic tool in Alzheimer's disease?
OBJECTIVE
Alzheimer's disease (AD) is a primary degenerative disease that progressively affects all brain functions, with devastating consequences for the patient, the patient's family and society. Rest regional cerebral blood flow (rCBF) could have a strategic role in differentiating between AD patients and normal controls, but its use for this purpose has a low discriminatory capacity. The purpose of this study was to evaluate whether the diagnostic sensitivity of rCBF single-photon emission computed tomography (SPECT) could be increased by using an episodic memory task provocation, i.e. memory-provoked rCBF-SPECT (MP-SPECT).


METHODS
Eighteen persons (73.2+/-4.8 years) with mild AD and 18 healthy elderly (69.4+/-3.9 years) were included in the study. The subjects were injected with (99m)Tc-hexamethylpropylene amine oxime (HMPAO) during memory provocation with faces and names, followed by an rCBF-SPECT study. The rCBF (99m)Tc-HMPAO SPECT images were analysed using statistical parametric mapping (SPM2). Peaks with a false discovery rate corrected value of 0.05 were considered significant.


RESULTS
On MP-SPECT, the AD group showed a significant rCBF reduction in the left parietal cortex in comparison with healthy elderly. At rest, no significant group differences were seen.


CONCLUSIONS
Memory provocation increased the sensitivity of rCBF-SPECT for the detection of AD-related blood flow changes in the brain at the group level. Further studies are needed to evaluate MP-SPECT as a diagnostic tool at the individual level. If a higher sensitivity for AD at the individual level is verified in future studies, a single MP-SPECT study might be sufficient in the clinical setting.
Sundström
Torbjörn
T
Department of Radiation Sciences, Diagnostic Radiology, Umeå University, Umeå University Hospital, 901 85, Umeå, Sweden.
Elgh
Eva
E
Larsson
Anne
A
Näsman
Birgitta
B
Nyberg
Lars
L
Riklund
Katrine A
KA
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods; D002560:Cerebrovascular Circulation; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008568:Memory; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime