Comparison of iodine-123-iomazenil SPECT and technetium-99m-HMPAO-SPECT in Alzheimer's disease.
This study was designed to elucidate a central type of benzodiazepine (Bz) receptor distribution in patients with Alzheimer's disease using SPECT with [123I]iomazenil (IMZ).


METHODS
Eight patients with probable Alzheimer's disease were studied. Benzodiazepine receptor imaging was performed 15 min (early) and 180 min (delayed) after intravenous administration of 167 MBq IMZ, sequentially, using hexamethylpropylene amine oxime (HMPAO) SPECT to evaluate regional cerebral perfusion.


RESULTS
Early IMZ-SPECT depicted areas of reduced uptake in sites of decreased cerebral blood flow (CBF), but each area of decreased uptake was extended wider than the area of hypoperfusion. Delayed IMZ-SPECT images demonstrated a similar pattern of decreased area of CBF; the affected region in Bz receptor bindings, however, was clearer and broader compared with that in either HMPAO-SPECT or early IMZ-SPECT. In comparison with the uptakes for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with unilateral cerebral infarction as a control group (n = 4), the patients with Alzheimer's disease showed distinctive bilateral frontal or parietal defects (p < 0.05).


CONCLUSIONS
Brain SPECT using IMZ may be more sensitive than CBF images in patients with Alzheimer's disease.
Fukuchi
K
K
First Department of Internal Medicine, Faculty of Health and Sports Science, Osaka University Medical School, Japan.
Hashikawa
K
K
Seike
Y
Y
Moriwaki
H
H
Oku
N
N
Ishida
M
M
Fujita
M
M
Uehara
T
T
Tanabe
H
H
Kusuoka
H
H
Nishimura
T
T
D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001921:Brain / Q000378:metabolism; D005260:Female; D005442:Flumazenil / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D019690:Technetium Tc 99m Exametazime; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D005442:Flumazenil; C063038:iomazenil