Iofetamine I 123 single photon emission computed tomography is accurate in the diagnosis of Alzheimer's disease

Alzheimer's disease (AD) is a chronic, organic mental disorder, or form of presenile dementia, in which the loss of intellectual function results from deterioration of the frontal and occipital lobes of the brain. It usually occurs between the ages of 40 and 60 years, and most commonly affects women. AD is characterized by the progressive, irreversible loss of memory, deterioration of intellectual function, indifference, speech and walking disorders, and disorientation. Within a few months to five years the disease may progress to complete loss of intellectual function. Brain function of patients with AD may be assessed by single photon emission computed tomography (SPECT), an imaging method using radioactive substances that release single photons or units of light energy. The effectiveness of SPECT using the radioactive substance iofetamine hydrochloride I 123 (IMP) in diagnosing AD was assessed in 58 patients with AD and 15 normal subjects. IMP with SPECT was 88 percent sensitive (identified individuals with AD) and 87 percent specific (identified individuals without AD) in diagnosing AD. The technique was 80 percent sensitive in identifying mild cognitive or intellectual abnormalities among 15 subjects without AD. IMP with SPECT showed that the parietal lobes of the brain were the most functionally impaired of all brain regions in patients with AD; this finding correlated with results from a cognitive function test known as the Blessed Dementia Scale. IMP with SPECT may serve as a useful, additional technique for diagnosing AD in the early, mild stage of the disease. (Consumer Summary produced by Reliance Medical Information, Inc.)