With a simple brain scan, providers can now better detect and monitor Alzheimer’s disease.
Dr. Tracy Vargas, a neurologist at UCHealth Neurology Clinic in Steamboat Springs, outlines the role of PET/CT scans in Alzheimer’s diagnoses below.
What is Alzheimer’s disease?
“Alzheimer’s is a brain disorder that gradually affects memory, thinking and ultimately the ability to carry out daily activity,” Vargas said. “It’s the most common cause of dementia and affects millions of people worldwide.”
Deposits of abnormal proteins – for instance, amyloid plaques and tau tangles – form in the brain and cause damage.
“These abnormal proteins damage brain cells especially in areas with a predilection for memory and thinking,” Vargas said.
How do PET/CT scans work?
Before a scan, the patient is injected with a small amount of a radioactive tracer, which binds to the abnormal proteins. During the scan, the tracer lights up, revealing the deposits and tangles, and helping doctors quickly determine the extent of the damage. Scans can also show areas of the brain with low glucose metabolism, which signals decreased brain activity.
How does a scan help with a diagnosis?
A positive scan can reveal potential disease early in the process, helping patients to prepare and consider treatment options, while a negative scan can help rule out Alzheimer’s.
Vargas cautions that a positive scan alone cannot be used to diagnose Alzheimer’s, as amyloid plaque deposits can also be caused by Lewy body dementia and can even be seen in cognitively normal adults.
To confirm an Alzheimer’s diagnosis, it’s critical to use the scan results in conjunction with a clinical assessment. Vargas also collects CSF, or cerebrospinal fluid, markers to aid in a diagnosis, as elevated levels of the abnormal proteins can signal Alzheimer’s.
“It helps me provide all the information that we can collect locally, then I will refer those patients to a neurobehavioral subspecialist,” Vargas said.
Recent developments in blood biomarkers may also help as an initial screening tool.
“These are emerging and will start to really help guide us in how aggressive we want to be in getting a diagnosis,” Vargas said.
Who should get a PET/CT scan?
Vargas typically uses PET/CT scans in cases with an unclear diagnosis, such as patients who may be early in the disease or those diagnosed with mild cognitive impairment that may be Alzheimer’s.
“Anyone under age 65 is a good candidate, as those patients can benefit from new therapies,” Vargas said. “Someone who is 85 years old with advanced symptoms is not a good candidate.”
Vargas encourages people to see their primary care provider, who can then refer the patient to a specialist for further tests and screenings.
It’s also important for family members to take concerns seriously.
“When cognitive concerns are brought by someone’s family, that should be a red flag,” Vargas said. “If someone comes in and says, ‘I think I have dementia,’ more times than not, they don’t.”
Why is an early diagnosis of Alzheimer’s helpful?
“It’s helpful to make a diagnosis early so you can get a treatment plan and coordinate care with patients while they’re still able to make decisions,” Vargas said. “It’s also helpful for their caretakers.”
Treatment options are limited for Alzheimer’s as it is a degenerative disease, which means it worsens over time. But new treatments are being developed and studied, such as IV infusion medications that are designed to remove plaques.
“More information is helpful across the board, especially as you think about what might need to be planned for,” Vargas said. “Oftentimes, patients will need to have a plan for what happens when family can’t take care of them. You don’t want to discover your mom has the disease because a safety event, such as a flooded home, has happened. For safety, planning and to identify available resources, it’s always helpful to have accurate information.”
Susan Cunningham writes for UCHealth Yampa Valley Medical Center. She can be reached at cunninghamsbc@gmail.com.
