COMPARISON OF IODINE-123-IOMAZENIL SPECT AND TECHNETIUM-99M-HMPAO-SPECT IN ALZHEIMERS-DISEASE

This study was designed to elucidate a central type of benzodiazepine (Bz) receptor distribution in patients with Alzheimer's disease using SPECT with [I-123]iomazenil (IMZ). Methods: Eight patients with probab le Alzheimer's disease were studied. Benzodiazepine receptor imaging w as performed 15 min (early) and 180 min (delayed) after intravenous ad ministration of 167 MBq IMZ, sequentially, using hexamethylpropylene a mine oxime (HMPAO) SPECT to evaluate regional cerebral perfusion. Resu lts: Early IMZ-SPECT depicted areas of reduced uptake in sites of decr eased cerebral blood flow (CBF), but each area of decreased uptake was extended wider than the area of hypoperfusion. Delayed IMZ-SPECT imag es demonstrated a similar pattern of decreased area of CBF; the affect ed region in Bz receptor bindings, however, was clearer and broader co mpared with that in either HMPAO-SPECT or early IMZ-SPECT. In comparis on with the uptakes for the normal cerebral hemisphere (ratio to the c ontralateral cerebellum) in patients with unilateral cerebral infarcti on as a control group (n = 4), the patients with Alzheimer's disease s howed distinctive bilateral frontal or parietal defects (p < 0.05). Co nclusion: Brain SPECT using IMZ may be more sensitive than CBF images in patients with Alzheimer's disease.