Fast Five Quiz: Alzheimer's Disease Workup

Jasvinder P. Chawla, MD, MBA


February 22, 2022

In the initial evaluation of patients with dementia, the American Academy of Neurology recommends structural neuroimaging with either a noncontrast CT scan or MRI. This is primarily to identify any lesions that may cause cognitive impairment and rule out potentially treatable causes of progressive cognitive decline, such as chronic subdural hematoma or normal-pressure hydrocephalus. Still, although brain MRIs or CT scans can show diffuse cortical and/or cerebral atrophy in patients with AD, these findings are not considered diagnostic.

Lumbar puncture is recommended only to rule out differential diagnoses such as normal-pressure hydrocephalus or central nervous system infection (eg, neurosyphilis, neuroborreliosis, cryptococcosis).

Brain SPECT scan or PET scan are not recommended in the routine workup of patients with typical presentations of AD. However, they may be an appropriate approach in patients with atypical AD presentations or when a form of frontotemporal dementia is suspected.

In clinical research studies, atrophy of the hippocampi on coronal MRI is considered a valid biomarker of AD neuropathology. Again, however, this approach is not used in routine diagnosis of AD.

Learn more about imaging in AD.


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