Understanding Today’s Alzheimer’s Diagnostic Tools Lisa Skinner

Hello everybody and welcome back to another new episode of the Truth, Lies, and Alzheimer's television show. I'm Lisa Skinner, your host, and today I want to address something. A while ago, I think it was like at least 6 months ago or longer, I was doing an episode on diagnostic tools that are available, and I said in the episode that currently the only way that we can accurately, definitively, and conclusively diagnose Alzheimer's disease is upon autopsy. And one of my listeners wrote in and said, but now there's PET scans. And this was, this comment was recent. So it's can accurately diagnose Alzheimer's disease. And I was thinking about that and I was asking myself, Lisa, did you miss something or has something changed? Because as you guys know, I strive to bring you the most accurate and up-to-date information that I can find, um, in my research. So I thought, okay, maybe something has changed. So I did a lot, a lot of research to bring you the most updated and accurate information on that subject because I think it's a really important thing for people to be aware of. How Alzheimer's disease is, is the ability of our healthcare providers to be able to give us an accurate diagnosis. So that's what I'm talking about today. So I've got the scoop and I probably went to about 10 different resources. About half of them, I believe, are listed in the show notes. But they all said exactly the same thing and they're all scientific resources like The Lancet and NIH. So I went to reliable resources and today I'm going to tell you what I uncovered. So if you have been experiencing notable changes in your memory or in your thinking, Your healthcare provider may recommend a PET scan to help determine if you may have signs of Alzheimer's disease. And I'm going to emphasize the word signs of Alzheimer's disease. So what I found out was that an amyloid PET scan is helpful in narrowing down and ruling out causes of concern for brain changes and can also help identify what that source might be. So what exactly is an amyloid PET scan? What does it measure in the brain? This is the explanation. An amyloid PET scan is an imaging test like an MRI or a CAT scan that measures the levels of amyloid plaques in our brains. During a PET scan, a radioactive tracer which attaches to the amyloid plaques is given to the patient intravenously. This tracer reveals the level of accumulation of this protein in the plaques in our brains. The amount of distribution of these plaques are thought to be indicators that Alzheimer's disease may be present, although they are not in themselves a definitive diagnosis. How does amyloid plaques relate to Alzheimer's disease? That has become the 64 bazillion dollar question because we're not sure anymore. Characteristics of dementia can include changes in thinking, memory, and behavior. While strong parallels exist among dementia, not all types of dementia are the same in origin or prognosis. And one distinction that is found in Alzheimer's disease is the presence of amyloid plaque buildup in the brain. So a person who demonstrates behaviors associated with dementia, who also has amyloid buildup, is most likely living with Alzheimer's disease. But there's a— there is an argument and a debate about that. An amyloid PET scan can be between 58 and 90% accurate for detecting the location and extent of these amyloid plaques in our brains and how your provider uses a PET scan along with other tests for Alzheimer's. If your healthcare provider wants to investigate possible dementia, an amyloid PET scan can help in ruling out Alzheimer's. If no plaques are present. Additional scans, biomarker assessments, cognitive evaluations, and health history work together to provide a clearer diagnosis. As part of this broad approach, the presence or absence of amyloid plaques is one piece of information contributing to a diagnosis. So how will your healthcare provider use your amyloid PET results to diagnose your condition? Your PET scan results will indicate whether or not you have plaques that are present in your brain. And while these plaques again are associated with Alzheimer's disease, This is— I want to emphasize this— a diagnosis is not made on the existence of plaques alone. Why? Because we have found through autopsy that there are many people who show symptoms, and severe symptoms in many cases, of dementia that do not have any plaques or tangles in their brains, and vice versa. There are many people who have been autopsied that do have plaques and tangles in their brains and are asymptomatic of dementia. So the jury's still out on that one. So why did your provider even order these cognitive tests and memory tests in addition to a PET scan? Because your, your PET scan in and of itself does not provide a diagnosis of Alzheimer's disease or other dementia. While it is a valuable tool in detecting the presence of amyloid plaques, that's, you know, valuable in self, but not conclusive. How do MRI scans and CT scans complement an amyloid PET scan for diagnosing Alzheimer's? While an amyloid PET scan is a highly specific tool that we are now using to detect the presence, location, and extent of these plaques, it still does not reveal other information about the brain that may be valuable in formulating a diagnosis. Additional neuroimaging scans, such as MRI scans, provide detailed imagery about the brain's anatomy and health. These scans can help identify atrophy in the brain, which is shrinkage, and cause— and can also help identify other causes of symptoms that may mimic dementia, for example, bleeding in the brain or the presence of a tumor. So the combination of these imaging scans provides a more comprehensive picture of brain activity and health, allowing for a more accurate explanation of the symptoms that you are presenting with. How PET scans help identify Alzheimer's disease in early stages. Identifying any dementia can be an involved process of diagnostic tools and assessments, and an amyloid PET scan is just one tool that can help focus a potential diagnosis by revealing the presence or absence of amyloid plaques. Plaques can be an indicator of potential Alzheimer's disease even before symptoms become apparent. The presence or absence of these plaques in the early stages of dementia can help shape a diagnosis and treatment for Alzheimer's or for other cognitive conditions that might be present. So the way that PET scans detect changes in the brain before the symptoms actually start appearing are to identify the presence of these plaques in individuals who may not have any symptoms of dementia yet. This is called preclinical Alzheimer's disease, and it can be helpful in watching for developing symptoms that may appear later, as well as consideration for early treatments that may delay the onset and severity of your symptoms. Now, amyloid PET scans are also helpful in identifying mild cognitive impairment, or MCI, where it shows, or it presents as a noticeable change in cognitive ability, but it still doesn't interfere significantly with your daily activities. The PET scan is helpful for individuals who have mild cognitive impairment, as it will reflect the presence or absence of the plaques in the brain, which can help your physicians or physician guide your treatment plan. If no plaques are found, other causes of mild cognitive impairment like a vascular condition a sleep condition like sleep apnea, or side effects of medications even can be investigated. If the plaques are found, then the likelihood of Alzheimer's as the source of mild cognitive impairment does increase, and your healthcare provider will help you consider your treatment options. If you remember, I don't know if you did or if you're just tuning into my show, not everybody who is diagnosed with mild cognitive impairment progresses to dementia, only if it's being caused by one of the brain diseases. If it's another condition like sleep apnea or a thyroid condition, then it's not necessarily going to progress, and it can be treated. Early detection of these plaques does help your healthcare provider understand more about the causes and prognosis of your cognitive changes. If the plaques are found, the likelihood of Alzheimer's disease being present and progressing increases, and knowing this, being able to implement appropriate interventions and early treatment to delay the onset of more significant symptoms can take place. So I'm going to explain to you now how the PET scan results fit into this pretty complicated diagnostic process. It helps narrow the possible reasons that you may— that may be causing you to experience your cognitive decline, or maybe what seems to be your cognitive decline. If the plaques do show up on your results, the likelihood of Alzheimer's once again increases, and your provider then may order further imaging. If no plaques are found on the results, then other types of dementia or underlying conditions are likely to be present, and your provider will develop an appropriate care plan specifically for you. So what can you expect from your PET scan results? The PET scan is now the best tool to find out if amyloid plaques are present. The detection of these plaques can help guide interventions, treatment, and care by your healthcare provider. And if no plaques are found, then the result will also help your healthcare provider decide what is best for you as an intervention, as a treatment, and for your care. If your results do show amyloid plaques, a lot of people are going to be worried that it means that they definitely have Alzheimer's disease. This is not the case, and I want to make sure you are very clear about this. The presence of the plaques is not in itself a diagnosis of Alzheimer's disease. If your provider finds any plaques, then additional comprehensive medical and cognitive assessments will help form a more accurate diagnosis. That can then be addressed with appropriate, appropriate medical care and lifestyle interventions. It helps shape a possible prognosis that can only be confirmed with other diagnostic tools like physical exams, cognitive assessments, and your medical history. So here are some commonly asked questions. About PET scans that you might want to take note of and ask your doctor. What exactly does a PET scan measure in the brain? Again, it's an imaging test that measures the buildup of amyloid plaques, which is a key marker of Alzheimer's disease. How is— how are these plaques related to Alzheimer's disease? They are abnormal protein deposits that can disrupt brain function and are strongly associated with Alzheimer's disease. How accurate is the PET scan for detecting Alzheimer's disease? Well, they're highly accurate, up to 90%, in identifying the plaques, but they are still not definitive for diagnosing Alzheimer's disease on their own. So that's when an MRI and a CAT scan can help complement the PET scan in the diagnostic process because they can provide detailed images of brain structure where PET scans don't do that. And the brain structure is a doctor's ability to be able to identify other conditions or brain changes that a PET scan alone cannot show. Another question that is frequently asked: Can a PET scan detect Alzheimer's disease before the symptoms appear? And the answer is yes, a PET scan can detect amyloid plaque buildup in the brain years before noticeable symptoms develop. So your next question is probably, well, if my amyloid PET scan shows plaques, do I have Alzheimer's disease? Not necessarily. While amyloid plaques once again are the hallmark of Alzheimer's, their presence does not always mean you have or even will develop the disease. Early detection allows for timely interventions, lifestyle changes, and treatment plans that may help slow disease progression and improve your quality of life. So those are some really important points that we need to emphasize about the value of, um, the, the PET scans that are currently available. Because we all know losing a loved one with dementia, a brain injury, or a neurological disease is such a difficult situation for families and be— and can be a very difficult experience, which can leave you and your family with so many unanswered questions. An autopsy can help to answer these questions. Um, many, if not most, dementias cannot be diagnosed with certainty without a tissue diagnosis, which happens at autopsy. And the reason why is because the brain cannot generally be biopsied during life due to its crucial functions. They can't get to the microscopic tissues. So this means that Alzheimer's disease and other diseases like Parkinson's, among many, many more, can only be definitively diagnosed through an autopsy. We call the autopsy— it's known as the gold standard of diagnosis for dementia. And the final answer in documenting and explaining the extent of disease and damage in other organic brain diseases such as Alzheimer's, Parkinson's, multiple sclerosis, a traumatic brain injury, Lewy body dementia, Pick's disease, ataxia, frontotemporal dementia, cerebral degeneration, strokes or post-stroke dementia, meningitis and encephalitis, hydrocephalus, HIV-associated dementia, myasthenia gravis, muscular dystrophy and other neuromuscular diseases, along with cerebral cerebral palsy, amyotrophic lateral sclerosis, or ALS, which is also commonly known as Lou Gehrig's disease, and brain tumors. So in conclusion, yes, a brain autopsy is, bottom line, still the only way to definitively confirm Alzheimer's. By examining brain tissue for plaques and tangles, because the conclusive or definitive diagnosis does involve the evaluation of microscopic brain tissues to define— to find the definitive signs of Alzheimer's disease. The plaques and tangles and modern techniques like biomarker tests, which are blood and spinal fluid tests, and PET scans now allow doctors to diagnose, um, Alzheimer's disease with a high accuracy rate of up to 90% while a person is still living and ruling out other causes. But while it's not 100% certain without an autopsy, these advanced tests alongside clinical evaluations provide strong evidence for a probable diagnosis, guiding treatment and research. So let's take a quick break and then we'll wrap this up when we come back. And don't forget to visit mindingdementia.com where you can subscribe to our weekly newsletter that is going to provide you with updated and current information, tips, resources, and also you can look around the website and find other valuable resources and tips for you. So don't go away, we'll be right back.

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Thanks for hanging in here with me. We're back, and I just want to thank everybody again. This is really important for me to address this because I do— it is so important to me to provide you with accurate information. So, um, hopefully this was helpful. I kind of did a deeper dive and a more detailed explanation of the purpose and the value of PET scans. And next week I'm gonna talk about the other, I'm gonna go into more detail about the other diagnostic tools and processes that doctors use to rule out or, um, make as accurate a diagnosis Alzheimer's disease or one of the other brain diseases that may be developing and how they go about doing that. So thanks for being here. I wish everybody a great, healthy, and happy rest of your week, and I'll see you again next week. Take care for now. Bye-bye.