What is the role of neuroimaging in the diagnosis of Alzheimer disease?

Updated: Apr 12, 2018
  • Author: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS; Chief Editor: L Gill Naul, MD  more...
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Answer

Answer

The current diagnosis of Alzheimer disease is made by clinical, neuropsychological, and neuroimaging assessments. Routine structural neuroimaging evaluation has long been based on nonspecific features such as atrophy, which is a late feature in the progression of the disease. More recently, a variety of imaging modalities, including structural and functional magnetic resonance imaging (MRI) and positron emission tomography (PET) studies of cerebral metabolism, have shown characteristic changes in the brains of patients with Alzheimer disease in prodromal and even presymptomatic states. [1, 2, 3]

Alzheimer disease was first described in 1907 by Alois Alzheimer. From its original status as a rare disease, Alzheimer disease has become one of the most common diseases in the aging population, ranking as the fourth most common cause of death. Alzheimer disease is a progressive neurodegenerative disorder characterized by the gradual onset of dementia. The pathologic hallmarks of the disease are beta-amyloid (Aβ) plaques, neurofibrillary tangles (NFTs), and reactive gliosis. [4, 5, 6] (See the images below.)

Coronal, T1-weighted magnetic resonance imaging (M Coronal, T1-weighted magnetic resonance imaging (MRI) scan in a patient with moderate Alzheimer disease. Brain image reveals hippocampal atrophy, especially on the right side.
Axial, T2-weighted magnetic resonance imaging (MRI Axial, T2-weighted magnetic resonance imaging (MRI) scan of the brain reveals atrophic changes in the temporal lobes.

Click here to view a slideshow presentation on Alzheimer Disease. Click here to view the Alzheimer Disease Radiograph slideshow.


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