大脑成像有助于诊断阿尔茨海默症

http://www.100md.com 2001年4月24日

     NEW YORK (Reuters Health) - Two brain imaging methods appear to be able to help doctors distinguish Alzheimer's disease from other kinds of dementia, which might lead to better diagnosis of the memory-robbing illness.

    It is difficult to tell the difference between Alzheimer's disease and other types of dementia, especially early in the course of the disease, according to Dr. Nick Fox and associates from The National Hospital for Neurology and Neurosurgery in London.

    Fox's team used a technique called magnetic resonance imaging (MRI) to measure the amounts of tissue in various parts of the brains of patients with Alzheimer's disease (AD) or semantic dementia (SD), a condition marked by the difficulty in remembering the names of things and in using words correctly. They looked at 10 patients with SD, 10 with AD, and 10 normal patients.

    The researchers found marked differences between AD and SD in those areas of the brain responsible for verbal and visual memory. Patients with SD had more severe deterioration on the left sides of their brain, while damage was symmetrical in AD. The findings appear in the April issue of the Annals of Neurology.

    In another study, Dr. William Jagust from the University of California Davis Medical Center in Sacramento and associates identified other abnormalities in the temporal lobes of brains affected by Alzheimer's disease. The temporal lobes, located beneath the temples, control auditory perception.

    This team of scientists used an imaging technique called SPECT to measure the activity of the temporal lobes of patients with AD or other dementias and compared the results with their doctors' diagnoses and with autopsy results.

    By identifying differences in the temporal lobes, SPECT significantly improved the accuracy of diagnosis of dementia, the researchers say in their April report in the journal Neurology.

    Jagust and colleagues suggest that using SPECT could increase the likelihood of a correct diagnosis of AD and thus allow doctors to use therapies that might not otherwise be used because of their high risks.

    Similarly, Fox and associates conclude that MRI not only offers the ability to accurately distinguish AD from SD but also provides clues regarding the location in the brain of the cause of semantic dementia.

    Together, these studies suggest two approaches doctors might use to sort out what's behind the dementia in their patients and begin to take appropriate steps to treat it.

    SOURCE: Annals of Neurology 2001;49:433-442; Neurology 2001;56:950-956., http://www.100md.com

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