Can MRI diagnose dementia? The answer is complicated…. It can definitely help in the diagnosis.
In Radiology, patients pose this question often. “Can MRI show if I have dementia?” In fact, we scan patients every day with a diagnosis of dementia, memory loss, Alzheimer’s, and confusion, among a variety of other neurological disorders.
The truth is that MRI is NOT the test to formally diagnose dementia. But to understand how MRI fits into the diagnosis process of a patient with suspected dementia, one must first understand how dementia is defined.
Dementia is a general term for neurocognitive deficiencies that impair or interfere with living a normal life due to memory deficits, decision making issues, or difficulty thinking clearly. Alzheimer’s disease is the most common and well known rendition of dementia, but there are other forms of the disease as well.
As we age, the capacity to remember, think sharply, or complete tasks independently inherently decreases. In fact, one could argue that we all show “signs of dementia” as we enter our golden years. This process is natural and considered a normal part of aging.
The term “dementia” starts to bubble up when an individual exhibits neurological deficits that cause them to stand out from their peers. This is usually noticed by people who know the individual best and can judge their cognitive decline, and see how it affects their daily lives.
What causes dementia is a much lengthier conversation and is a very debated subject among healthcare professionals. With this being said, there are some known structural processes that can cause a patient to exhibit symptoms of dementia. This is where MRI comes in!
When healthcare providers order MRI studies with a diagnosis of “dementia,” what they really mean is that the patient is suffering from symptoms associated with dementia and they want to rule out physical abnormalities that could be causing these issues APART from standard, idiopathic (of no specific or known cause) dementia.
An MRI is a high-resolution imaging tool that can reveal structural abnormalities within the body. MRI of the brain is one of the most common orders we receive. On a daily basis, we evaluate patients for acute strokes, brain tumors, multiple sclerosis, inner ear tumors, and a variety of other conditions.
For dementia patients specifically, we are looking for reasons OTHER than dementia that could be causing the patient to exhibit symptoms traditionally assigned to dementia. While dementia is a common diagnosis among older adults with neurological deficits, it is important to make sure that structural abnormalities are not causing their symptoms. A patient who is exhibiting memory loss, decision-making concerns, or disorientation may be suffering from an organic disease process that can be treated and potentially reduce or completely eliminate their symptoms. In any case, if a physical diagnosis is rendered, a provider can properly treat their patient. The following are some common abnormalities we see in MRI that can mimic the symptoms of bonafide dementia.
Normal Pressure Hydrocephalus
Normal Pressure Hydrocephalus, frequently abbreviated as NPH, is a condition in which cerebrospinal fluid builds up within the ventricles of the brain. In a normal patient, the ventricles release cerebrospinal fluid through the brain and spinal cord, giving these areas the cushion and nutrients that cerebrospinal fluid provides. If the ventricles do not drain the cerebrospinal fluid, the ventricles swell and push outward on the rest of the brain. NPH can produce neurological symptoms including cognitive dysfunction, ambulatory issues, and loss of bladder control. All of these symptoms can be seen in patients with idiopathic dementia. NPH can be easily seen in a routine MRI of the brain.
The blue arrows are pointing to the first and second ventricles of the brain. They appear dark on this specific image type. On the left image above, you can see an example of what normal ventricles look like. On the right image above, you can see ventricles that are enlarged and inherently pushing on the rest of the brain.
Luckily for patients with this diagnosis who are caught early enough, NPH can often be alleviated. Upon successful treatment, patients often have reduced symptoms or none at all.
Small Vessel Disease / Vascular Dementia
The brain is full of small arteries that supply necessary oxygen-rich blood and nutrients. When these vessels start to chronically deteriorate, become occluded, or rupture, it causes damage to the brain. This process is referred to as Small Vessel Disease, or as it refers to the cognitive symptoms that are affected, Vascular Dementia. Symptoms include memory decline, gait instability, mental fog, and neuromotor deficits.
Small Vessel Disease is typically a chronic and progressive process that is caused by weakened blood vessels. This can be genetic or caused by chronic hypertension, high cholesterol, or chronic use of certain drugs. Long-term smoking can also cause damage to the small arteries of the brain. Often in imaging, the damage caused by small vessel disease is diffuse and not limited to a certain spot. In the image below you can see white spots throughout the brain. Some of these spots are highlighted with blue arrows. These white spots represent many small areas of the brain that have been damaged by chronic Small Vessel Disease.
While this type of damage is not reversible, Small Vessel Disease is important to diagnose and treat to the best of our ability. Reducing blood pressure and/or cholesterol, or habits that are causing the disease process to progress, are critical to slowing down the disease progression and associated symptoms.
While strokes are often thought of as dramatic events with trips to the emergency room, brain surgery, and devastating results, many times strokes happen quietly and with very few symptoms. In fact, the majority of strokes do not even trigger a trip to the emergency room for the affected patient.
A stroke oftentimes referred to as a cerebrovascular accident (CVA) is an event in which blood to the brain is interrupted or stopped. This can be due to a blood clot or a ruptured blood vessel. The brain, in turn, rapidly becomes damaged and produces symptoms almost immediately. The problem with these symptoms is that they can be obvious or extremely subtle.
The more traditional and apparent symptoms of a stroke are facial drooping, disorientation, slurred speech, or loss of consciousness. Patients who exhibit these symptoms are usually aware that there is a problem. Often, these symptoms are so prolific that anyone around the affected individual can see that something is wrong.
Unfortunately, many strokes are less obvious, and the symptoms are very hard to detect. In a large percentage of cases, they produce no clear symptoms at all. Some patients only experience a mild headache, fatigue, or vertigo. Many of us have these types of symptoms at various times throughout our life and think nothing of it; much less that part of our brain is dying!
In these subtle cases, symptoms can manifest themselves later in time and be confused with mental illness, namely idiopathic dementia. Patients who have experienced strokes are typically older and in the age category in which dementia is not out of the question in the first place.
From a diagnostic standpoint, it is important to evaluate the brain with an MRI to look for strokes, whether new or old, that could cause the patient symptoms that are associated with dementia. Patients who have experienced strokes can exhibit a wide variety of short and long-term symptoms including disorientation, imbalance, confusion, and memory loss. If the stroke is not diagnosed, it can lead to mismanagement of treatment or, worst-case scenario, additional strokes and damage to the brain.
Strokes are fairly easy to see in MRI due to the nature of how they affect normal blood flow to the brain. In the image below, you can see a large white area in a patient’s brain. This represents the restricted blood flow to the specific area of the brain being affected by the stroke.
While the damage of a stroke can rarely be reversed, it is important to diagnose a stroke and, more importantly, figure out why it happened. Treatment of the underlying condition that may have caused the stroke can prevent further damage. It is also extremely important to realize that treatment of dementia is very different from the treatment required for patients that have experienced a stroke.
Many conditions can cause symptoms that are associated with dementia. Since the disease is difficult to diagnose in the first place, it’s important to figure out what’s NOT causing symptoms.
If you or a loved one are suffering from symptoms of dementia, please make it a priority to see your primary care doctor or neurologist as soon as possible. Preventative medicine, as well as catching disease processes at an early stage, can make the difference between lifelong symptoms and the path to healing.
The Radiology Clinic is here to provide high-quality, high-resolution imaging for patients who are experiencing symptoms of dementia and need answers. Our team of board-certified fellowship-trained neuroradiologists are specially trained to evaluate neurological MRI studies. We work closely with our referring medical community to provide answers to the clinical questions surrounding dementia and its origins. If you would like to schedule an appointment, or if you have questions about the MRI process itself, please call us at 301-217-0500, or email us at firstname.lastname@example.org.