MRI scan may help doctors spot early signs of Alzheimer’s

A new type of MRI scan may help doctors spot early signs of Alzheimer’s disease in the brain, paving the way for earlier treatment of the disease.

Researchers in France have developed an automated system for measuring brain tissue loss using magnetic resonance imaging (MRI) technology to help doctors diagnose Alzheimer’s disease and mild cognitive impairment. Many people with mild cognitive impairment may go on to develop dementia.

In Alzheimer’s disease, the buildup of certain proteins in the brain leads to brain cell and brain tissue death; the hardest-hit part of the brain is the hippocampus, which affects memory.

The automated MRI system helps in diagnosing Alzheimer’s disease by speeding up the process of visually measuring shrinkage in the hippocampus consistent with Alzheimer’s disease.

Diagnosing Alzheimers disease can be difficult. It may take several diagnostic tests and a full physical exam by the doctor to diagnose this disease. There are two abnormal structures in the brain associated with Alzheimer’s disease — amyloid plaques and neurofibrillary tangles:

  • Amyloid Plagues — Amyloid plaques are sticky clumps or patches of protein found surrounded by the debris of dying nerve cells in the brain of Alzheimer’s patients.

  • Neurofibrillary Tangles — These are the damaged remains of protein called tau, which are required for the normal functioning of the brain. In people with Alzheimer’s, threads of tau protein become twisted, which researchers believe may damage neurons and cause them to die.

  • Evaluations — A series of evaluations will test memory, reasoning, vision-motor coordination and language skills.

  • Interviews — An interview with the patient and another person close to the patient, such as a relative, spouse or close friend who can provide examples of memory loss and functional decline.

  • Laboratory Tests — Lab tests, such as blood and urine tests, may provide information about problems other than Alzheimer’s that may cause dementia

  • Medical History — Information about current mental or physical conditions, prescription and nonprescription drug use, and family health history will be collected.

  • Brain Scans — These test will be performed to detect other possible causes of dementia such as stroke.

“Visually evaluating the atrophy of the hippocampus is not only difficult and prone to subjectivity, it is time-consuming,” says researcher Olivier Colliot, PhD, of the Cognitive Neuroscience and Brain Imaging Laboratory in Paris, in a news release. “As a result, it hasn’t become part of clinical routine.”

“The performance of automated segmentation is not only similar to that of the manual method, it is much faster,” says Colliot. “It can be performed within a few minutes versus an hour.”

 

“Combined with other clinical and neurospychological evaluations, automated segmentation of the hippocampus on MR images can contribute to a more accurate diagnosis of Alzheimer’s disease,” says Colliot.

SOURCES:
Colliot, O. Radiology, July 2008; vol 248: pp 194-201.
News release, Radiological Society of North America
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