16 Feb, 2023

Brain Scan for Dementia Imaging Guide: Prediction and Uses of MRI and CT for Dementia Diagnosis

Doctors commonly use MRI scans to confirm dementia diagnoses, but earlier scans could predict dementia before any symptoms are detected. This article will explore what dementia is, how it is diagnosed, and whether it can be prevented or predicted.

What is dementia?

Dementia is a general term used to group certain types of cognitive decline, such as memory loss, changes in speech and language usage, issues with reasoning, and other symptoms that become severe enough to interfere with daily life.

Dementia itself isn't a disease, it is an umbrella term for a set of symptoms associated with cognitive impairment.

Alzheimer's is a type of dementia, which makes up the majority of cases (60-80%) along with vascular dementia (5-10%) and several other rarer forms such as Huntingdon's disease. Around 55million people currently live with dementia, and there are an estimated 10million diagnoses every year.

Another form of dementia is vascular dementia, which is related to issues caused by reduced blood flow, and the resulting lack of oxygen to your brain tissue as a result of impaired blood supply.

Can dementia be cured?

Unfortunately, there is currently no cure for dementia, but earlier diagnosis can provide more time for planning, better management of symptoms, and the ability to maximise treatment potential. There is also extensive dementia research underway into prevention and cure.

What are the symptoms of dementia?

Symptoms of vascular dementia can often overlap with those of other types of dementia such as Alzheimer's disease. In fact, the term 'dementia' is used to describe the group of symptoms, such as memory loss, confusion, or changes to speech and thought processes that are caused by diseases such as vascular dementia or Alzheimer's disease.

People with vascular dementia tend to experience problem-solving issues, changes to their thinking speed, confusion and issues with organising their thoughts and actions, rather than the memory loss associated with Alzheimer's disease progression, for example.

How to diagnose vascular dementia using imaging: What does a brain scan show for dementia?

MRI brain scan for dementia

There is no single test that can definitively diagnose dementia, so doctors and health professionals rely on a combination of assessments such as memory tests, diagnostic imaging, and blood tests.

MRI scans are used to produce detailed images of the brain tissue and blood vessels. In NHS care, MRI brain scans are commonly used as the last step of diagnosis, after cognitive decline is noticed in preliminary tests. This is because MRI images can help identify the type and cause of dementia, such as blood vessel damage linked to vascular dementia, as well as shrinkage (atrophy) in areas of the brain associated with Alzheimer's disease.

However, recent research has shown that MRI scans could be used as the first step in dementia diagnosis, rather than as the final confirmation. If you have concerns about memory loss, getting a private MRI scan could help spot changes in your brain tissue, especially to the hippocampi structures, which tend to be the first areas affected by dementia.

MRI scans can provide the information necessary to predict who will experience cognitive decline with 89% accuracy, as far as 2.6 years before memory loss is clinically detectable.

CT scans for dementia diagnosis

CT scans are also commonly used for dementia diagnosis, as they can identify many of the same issues as MRI scans, in a faster procedure. However, MRI scans are better for identifying brain atrophy, damage from small strokes, or subtle ischemia, which is a mild brain injury caused by impaired blood flow to the brain and the resulting reduced oxygen supply.

Can MRI scans predict dementia?

With regular brain scans, you can ensure abnormalities are noticed and assessed as soon as possible. Early diagnosis is key to ensuring the right support and treatment, and it can also provide you and your loved ones with the reassurance you need, or the precious gift of additional time.

Preventative MRI scans can provide clues to potential dementia in number of different ways. However, some of these preventative methods are still being researched and may not be widely available:

  • A technique called diffusion tensor imaging is an effective method of assessing any damage to white matter in the brain. It measures how water molecules move across the white matter, which is vital to communication between different parts of the brain. If water movement is abnormal, it could be a sign of damage that could lead to cognitive impairment. Researchers found that diffusion MRI could predict who would go on to develop dementia with 89% accuracy, simply based on the water movement in the white matter.

  • Databases are currently being compiled for preventative brain scan images, where markers for MCI (mild cognitive impairment) can be mapped across a wide set of scans. People who have MCI have a tenfold increased risk of developing Alzheimer's, and it is is noticeable before dementia symptoms arise. Scientists are developing algorithms to compare your brain scan with the markers in existing datasets, to notice the warning signs for dementia earlier, and help you to maximise treatment potential. Dementia research around the use of artificial intelligence is growing.

Can dementia be prevented if you are at risk?

While there is no proven way to prevent dementia, and there is no vaccine against it, there are many lifestyle factors that can impact your risk of getting dementia. Addressing these factors can reduce your risk of dementia by up to a third.

Heart and blood vessel health

  • Conditions affecting the heart and blood vessels, such as high cholesterol, high blood pressure, obesity, and type 2 diabetes, can all increase your risk of heart disease and dementia.

  • Eating a healthy, balanced diet and exercising regularly are key ways you can reduce your risk of heart disease, as well as dementia. Blood sugar levels that are either too high or too low can also link to dementia.

  • Stopping smoking reduces heart health risks and the associated links to dementia.

  • Seeing your GP regularly in middle age can help you manage blood glucose levels, cholesterol, and blood pressure through tests and check-ups.

Physical health

  • There is a direct link between regular physical exercise and a healthier brain. Following the national guidelines for exercise (150 minutes of moderate activity, or 75 minutes of vigorous activity per week) can lower your risk of dementia, as well as reduce other risk factors such as obesity and high cholesterol.

  • Break up extended periods of sitting down, by standing while on the phone, going for a walk, or doing some stretches while you boil the kettle during your coffee break.

  • Building an optimal sleep routine is important for physical and mental health. Make sure you get the recommended 6-9 hours of sleep every night.

Mental health

  • Just like physical exercise, mental exercise is key, because it can contribute to building new brain cells and strengthens communication between them.

  • Playing games such as sudoku or crosswords, using brain-teaser apps, or even doing colouring books can increase brain health. Learning a new language can also strengthen memory and thinking skills, and could delay the risk of dementia by up to 5 years.

  • Stay social to avoid loneliness and isolation. Set time aside to call your friends and family, try out new group activities in your local area, or strike up conversations when you go out.

How much is a brain scan for dementia?

Brain scans vary in price, but the cost of a private MRI brain scan starts from £350, while a CT brain scan costs upwards of £420. Both scan types include a pre-scan clinician consultation, fast referral, online results, and a telephone follow-up.

Next steps

  • Book a private MRI scan or CT scan near you today, with a quick referral and fast results from our expert clinical team

  • Find out more about MRI scans on our news page


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