Key takeaways:
- The term “brain scan” can refer to MRI scans, CT scans, and PET scans, or a combination.
- Brain scans may help evaluate head injuries, strokes, Alzheimer’s disease, and brain cancer.
- MRI is most suitable for health screening because it doesn’t use ionising radiation.
- Ezra’s MRI scan with skeletal and neurological assessment includes a brain scan for signs of neurodegeneration and a brain age analysis.
The term “brain scan” can refer to several types of imaging techniques like magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET)1–3.
There are hundreds of reasons your healthcare provider might order a brain scan. Whether you need a brain scan or not largely depends on a cognitive assessment, a cognitive functions test about how you’re feeling, your level of consciousness, and vital signs4.
Note: This article is for informational purposes only and should not be taken as medical advice.
If you are experiencing neurological symptoms such as a debilitating headache, a change in your level of consciousness, seizures, unexplained weakness, or difficulty speaking, reading, or writing, please seek prompt medical care or emergency services.
What Is a CT Brain Scan?
A CT scan or CAT scan, which stands for computed tomography, can detect bleeding, swelling, and skull fractures. CT uses X-ray data and a computer to generate 3D images of structures.
Brain CT scans help surgeons decide if a brain injury, stroke, or herniation (acute swelling that causes the brain to shift in the skull) requires immediate surgery.
CT scans are safe for most people. However, because CT scans expose you to ionizing radiation, they may increase your lifetime cancer risk slightly. As with all tests, it’s best to weigh the risks and benefits2,5.
What Is a Magnetic Resonance Imaging (MRI) Brain Scan?
MRIs work by aligning the hydrogen molecules in your cells using powerful magnets. As the molecules absorb the energy from the radiofrequency waves, they emit a signal in response.
With software help, the data becomes a detailed image. Bodily structures with high water content, like the soft tissues and organs such as the brain and kidneys, create the most contrast and therefore produce better MRI images6.
Because MRI machines use strong magnetic fields, this type of medical imaging isn’t right for everyone. Let your provider know if you have any implanted medical devices (like pacemakers or defibrillators) and surgical hardware (pins, plates, screws, and rods), dental implants, metal foreign bodies, tattoos, and permanent make-up1.
What Types of MRI Are Available?
There are several types of MRI available. If you are claustrophobic, you may inquire about using an open-MRI which, as its name suggests, is open on at least three sides. With no tunnel to fit into, open MRI scanners can accommodate more body types7.
However, a major drawback of open MRIs is poor image quality. Because of its open-air design, the scanner loses some of its magnet strength. Instead of an open MRI, MRI professionals such as those at Ezra use 3T MRI scanners. These scanners feature a larger bore with a shorter tunnel, a stronger magnet, and faster scan times8.
PET Scan
Positron emission tomography, or PET, is a type of nuclear medicine scan that can be used with a CT scan or an MRI to measure the metabolic activity of cells within brain tissue. It can be helpful in the early detection of cancer and neurological diseases like Alzheimer’s disease9.
During a PET scan, technicians inject a radiotracer agent into an IV (intravenous catheter). The radiotracer travels through your bloodstream, including the area the PET is scanning, enabling the production of detailed images of the area of interest3.
When Is Brain Scanning Used?
Brain scans play an important role in helping healthcare practitioners diagnose and rule out many medical conditions in all healthcare settings.
1. Traumatic Head Injuries
There are two types of head injuries that sometimes require a brain scan.
A closed head injury means there is trauma to the skull, but the skin and soft tissues covering it remain intact. An open head injury features a visible wound.
Signs and symptoms of a head injury may not appear until hours or even days later. Your provider may order a brain scan to look for evidence of bleeding, brain swelling, and skull fracture10.
A CT scan is usually the first imaging test to help diagnose a head injury. CT scans may help radiologists notice signs of bleeding, swelling, and skull fractures11.
MRI may help evaluate head injuries over 48 hours old. MRI is best for evaluating post-traumatic or secondary head injuries, as well as evaluating cranial blood flow, and may offer insight into prognosis12.
2. Stroke
A stroke occurs when your brain doesn’t get enough oxygen. This can happen in a couple of different ways.
During an ischemic stroke, blood flow to the brain slows due to a clot or other obstruction. During a haemorrhagic stroke, bleeding into the brain tissue occurs, which happens because of high blood pressure or a ruptured or leaking aneurysm (a weak area in the vessel wall)13,14.
For stroke imaging in the acute phase, when the stroke is actively happening, doctors will order either a non-contrast head CT scan or an MRI to classify the stroke. An MRI is more sensitive for spotting acute ischemic strokes, especially those presenting during the first 12 hours of onset15.
3. Brain Cancer
Brain tumours occur when abnormal cells within the brain grow unchecked. Primary brain cancer starts in the brain and rarely spreads. However, the most common type of brain cancer is secondary and occurs when cancer cells from elsewhere in the body spread to the brain16.
Brain scans, like MRI, can help differentiate between brain cancer and benign lesions as well as assist in pre-surgical planning. PET may be used to evaluate for recurrence at yearly intervals after successful treatment17.
4. Alzheimer’s Disease
Diagnosis of Alzheimer’s disease relies upon clinical signs, symptoms, medical history, and psychological exams18.
Current research shows that combining neuroimaging techniques like MRI and PET may help medical professionals diagnose diseases like Alzheimer’s and dementia earlier19.
5. Brain Health Screening
Even if you are a healthy person with no neurological symptoms, you may be curious about what an MRI brain scan could tell you about your health. In this case, you might be interested in an elective brain scan. At Ezra, multi-organ MRI screening, including the brain, can reveal signs of neurodegeneration earlier.
Stay on Top of Your Health With Routine MRI Scans
Most people are surprised to learn that getting a brain MRI can be a part of their annual wellness check, including for possible early cancer. There is no need to wait until you are experiencing symptoms.
Find peace of mind, or get early signs about potential health issues so you can prepare to tackle them. Get started with your first comprehensive MRI to form a baseline, then stay in control with a follow-up scan every year. This can help you monitor your health and have the best chance at catching important changes before they become a problem.
You can book an Ezra MRI scan with skeletal and neurological assessment online in approximately five minutes. You don’t need an order from your doctor, but you can keep your healthcare team in the loop by sharing your results. Book your scan today.
Understand your risk for cancer with our 5 minute quiz.
Our scan is designed to detect potential cancer early.
References
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2. NHS. CT scan. NHS. 2023. Accessed December 18, 2025. https://www.nhs.uk/tests-and-treatments/ct-scan/
3. NHS. PET scan. NHS. 2025. Accessed December 18, 2025. https://www.nhs.uk/tests-and-treatments/pet-scan/
4. Harvey PD. Clinical applications of neuropsychological assessment. Dialogues Clin Neurosci. 2012;14(1):91-99. doi:10.31887/DCNS.2012.14.1/pharvey
5. British Heart Foundation. What is a CT scan of the brain? British Heart Foundation. 2018. Accessed December 18, 2025. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/tests/ct-scans-of-the-brain
6. Weishaupt D, Köchli VD, Marincek B. How Does MRI Work? Springer; 2003. doi:10.1007/978-3-662-07805-1
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9. Alzheimer’s Society. What can PET scans tell us about dementia? Alzheimer’s Society. 2017. Accessed December 18, 2025. https://www.alzheimers.org.uk/blog/pet-scan-dementia-explained
10. NHS. Head injury and concussion. NHS. 2025. Accessed December 18, 2025. https://www.nhs.uk/conditions/head-injury-and-concussion/
11. Currie S, Saleem N, Straiton JA, Macmullen-Price J, Warren DJ, Craven IJ. Imaging assessment of traumatic brain injury. Postgrad Med J. 2016;92(1083):41-50. doi:10.1136/postgradmedj-2014-133211
12. Chiara Ricciardi M, Bokkers RPH, Butman JA, et al. Trauma-Specific Brain Abnormalities in Suspected Mild Traumatic Brain Injury Patients Identified in the First 48 Hours after Injury: A Blinded Magnetic Resonance Imaging Comparative Study Including Suspected Acute Minor Stroke Patients. J Neurotrauma. 2017;34(1):23-30. doi:10.1089/neu.2015.4338
13. NHS. Causes of a stroke. NHS. September 19, 2024. Accessed December 18, 2025. https://www.nhs.uk/conditions/stroke/causes/
14. Stroke Association. Types and causes of stroke. Stroke Association. 2025. Accessed December 18, 2025. https://www.stroke.org.uk/stroke/types
15. Danziger A, Velayudhan V, Pawha P, Tanenbaum L, Patel A. Stroke Imaging: Practice Essentials, Computed Tomography, Magnetic Resonance Imaging. Medscape. December 4, 2024. Accessed December 18, 2025. https://emedicine.medscape.com/article/338385-overview?form=fpf
16. Cancer Research UK. Primary and secondary brain tumours. Cancer Research UK. 2023. Accessed December 18, 2025. https://www.cancerresearchuk.org/about-cancer/brain-tumours/types/primary-secondary-tumours
17. Cancer Research UK. Tests to diagnose brain tumours. Cancer Research UK. 2023. Accessed December 18, 2025. https://www.cancerresearchuk.org/about-cancer/brain-tumours/getting-diagnosed/what-are-the-tests
18. Alzheimer’s Society. Tests and scans to diagnose dementia. Alzheimer’s Society. December 2023. Accessed December 18, 2025. https://www.alzheimers.org.uk/about-dementia/dementia-diagnosis/how-to-get-dementia-diagnosis/tests-and-scans
19. Aberathne I, Kulasiri D, Samarasinghe S. Detection of Alzheimer’s disease onset using MRI and PET neuroimaging: longitudinal data analysis and machine learning. Neural Regen Res. 2023;18(10):2134-2140. doi:10.4103/1673-5374.367840
