Brain Imaging: A standard workup for AD often includes brain imaging tests or structural imaging using magnetic resonance imaging (MRI) or computed tomography (CT). Imaging tests are mainly used to rule out other conditions that might cause similar symptoms to AD. In addition, imaging tests can also identify tumors, small or large strokes, damage from severe head trauma, or fluid buildup in the brain.
Positron Emission Tomography (PET): This type of imaging is often used to identify disease processes in the brain by using a low-level of radioactive tracer injected into the blood to reveal a particular feature within the brain. There are three types of PET imaging technique that may be used:
- Fluorodeoxyglucose (FDG) PET: This scan shows areas of the brain in which nutrients are poorly metabolized. This scan can identify patterns of degeneration which may help distinguish between Alzheimer's disease and other types of dementia.
- Amyloid PET: This imaging technique can measure amyloid deposits in the brain. Although it is primarily used in research, it may be used if a person has unusual or very early onset of dementia symptoms.
- Tau PET: This imaging measures the neurofibrillary tangles in the brain. It is used exclusively in research. No insurance company covers this testing for AD diagnosis.
Routine Laboratory Tests: Routine blood and urine lab tests may also be employed to rule out other potential conditions or disorders causing memory loss and confusion. Basic hematology, chemistry, and urinalysis workups are typically used to assess the patient’s overall health.
Genetic and Biomarker Tests: Research studies have been able to identify certain genes that may be involved in the development of AD and that may increase the risk of developing the disease. Although genetic tests are available, the use of genetic testing for routine AD evaluation is not recommended at this time. However, genetic testing on individuals with a family history of early-onset AD may have some benefit. In addition, many clinical studies have demonstrated that certain biomarkers, measured in CSF or Blood, may be of value in the diagnosis and treatment of AD. While it is clear that AD is not currently preventable, studies using certain CSF or blood biomarkers may be of value in allowing for earlier diagnosis and earlier treatment of AD which in turn could delay advanced stages of the disease giving the patient more quality time. (Please see the next sections for more details).