Brain MRA, or magnetic resonance angiography, is commonly offered as an optional examination in comprehensive health checkup programs in Korea.
Unlike brain MRI, which primarily evaluates brain tissue, MRA is designed to evaluate the arteries of the brain.
In health screening, the main purposes of brain MRA are to look for:
- intracranial aneurysms
- intracranial arterial stenosis
- other major vascular abnormalities
Brain MRA is particularly convenient for screening because it does not use ionizing radiation and is usually performed without intravenous contrast.
However, routine MRA screening is not necessary for every healthy adult.
What Is Brain MRA?
For routine intracranial screening, the most commonly used technique is time-of-flight MRA, or TOF MRA.
TOF MRA uses the movement of blood to generate vascular signal, so gadolinium contrast is usually unnecessary.
It can evaluate major intracranial arteries, including:
- internal carotid arteries
- middle cerebral arteries
- anterior cerebral arteries
- posterior cerebral arteries
- basilar artery
- intracranial vertebral arteries
Brain MRA is often performed together with brain MRI, but the two examinations have different purposes.
What Can Brain MRA Find?
Intracranial aneurysms
One of the main reasons for performing brain MRA in a health checkup is to detect unruptured intracranial aneurysms.
Many small aneurysms cause no symptoms and are discovered incidentally.
If an aneurysm is found, its significance depends on several factors, including:
- size
- location
- shape
- patient age
- smoking
- hypertension
- family history
- change over time
Finding an aneurysm does not automatically mean that treatment is required.
Many small aneurysms are monitored with follow-up imaging rather than treated immediately.
Intracranial arterial stenosis
MRA can also detect narrowing of major intracranial arteries.
This may be related to atherosclerosis or other vascular disease and can be relevant to stroke risk.
MRA can show the location and approximate severity of narrowing, although it has limitations when measuring the exact degree of stenosis.
Who Should Consider Brain MRA?
Routine brain MRA is not recommended simply because it is available in a premium health checkup package.
Aneurysm screening becomes more relevant in people at increased risk, such as those with:
- strong family history of intracranial aneurysm or aneurysmal subarachnoid hemorrhage
- certain hereditary conditions associated with cerebral aneurysms
- previous intracranial aneurysm
- other selected high-risk situations
The American College of Radiology considers head MRA without IV contrast usually appropriate for cerebral aneurysm screening in high-risk individuals.
Family history deserves particular attention. Multiple close relatives with intracranial aneurysm or aneurysmal subarachnoid hemorrhage generally carry more significance than a single distant relative.
For people without specific risk factors, the benefit of routine aneurysm screening is less clear.
MRA may also be considered when there is a specific reason to evaluate intracranial arterial disease rather than simply for general screening.
What Are the Limitations of TOF MRA?
TOF MRA is useful, but it is not a perfect representation of the arterial lumen.
Because the technique depends on blood flow, slow or turbulent flow can produce artifacts.
As a result, MRA may sometimes:
- overestimate arterial stenosis
- make slow-flowing vessels appear narrowed
- create artifacts near vessel bends or branch points
- incompletely characterize very small aneurysms
- occasionally make overlapping vessels resemble an aneurysm
This is particularly relevant when evaluating stenosis.
A vessel that looks significantly narrowed on TOF MRA may sometimes appear less stenotic on another vascular examination because the apparent narrowing was partly related to flow artifact.
What Happens If MRA Shows an Abnormality?
An abnormal MRA does not always provide the final answer.
If MRA shows a suspected aneurysm, significant arterial stenosis, or an indeterminate vascular abnormality, CT angiography (CTA) may be performed for more detailed evaluation.
CTA can provide additional information about:
- aneurysm size, shape, and neck
- relationship to nearby vessels
- degree and length of arterial stenosis
- vascular calcification
- detailed vascular anatomy
CTA has high spatial resolution and is less dependent on flow-related signal than TOF MRA.
This can be particularly helpful when TOF MRA suggests stenosis but flow artifact makes its true severity uncertain.
For aneurysms, CTA may also help define the morphology and surrounding vascular anatomy more precisely.
CTA does require iodinated IV contrast and ionizing radiation, so it is generally used when additional anatomical information is needed rather than simply added to every screening MRA.
In selected cases, particularly when non-invasive studies remain inconclusive or an intervention is being planned, catheter angiography may be required.
Brain MRI and Brain MRA Are Different Tests
This distinction is important when comparing health checkup packages in Korea.
You may see:
- brain MRI
- brain MRA
- brain MRI + MRA
These are not interchangeable.
Brain MRI primarily evaluates brain tissue and is useful for findings such as:
- cerebral infarctions
- white-matter changes
- brain tumors
- cerebral microbleeds
- other structural brain abnormalities
Brain MRA primarily evaluates the arteries and is useful for detecting:
- cerebral aneurysms
- intracranial arterial stenosis
- other vascular abnormalities
If you want both detailed evaluation of the brain and screening of cerebral arteries, check whether the package actually includes both MRI and MRA.
Does MRI Scanner Quality Matter for MRA?
Yes.
MRA image quality depends on factors such as:
- spatial resolution
- signal quality
- MRA protocol
- acquisition time
- patient motion
- post-processing
- technologist experience
- radiologist interpretation
Brain MRA is commonly performed on 1.5-T or 3-T MRI scanners.
Both can produce diagnostic examinations, although 3-T systems can provide higher signal and may offer advantages when evaluating small intracranial vessels.
However, scanner field strength alone does not determine examination quality.
A well-designed MRA protocol and good image acquisition remain important.
How Much Does Brain MRA Cost in Korea?
The cost varies depending on the hospital, screening center, MRI system, and whether MRA is performed alone or together with brain MRI.
As a rough guide, brain MRA may cost around ₩300,000–₩500,000, or approximately US$210–350, based on an exchange rate of about US$1 = ₩1,417 in August 2026.
The effective cost may be lower when MRI and MRA are included together in a comprehensive health checkup package.
When comparing packages, check whether the listed examination includes:
- MRI only
- MRA only
- MRI + MRA
Do You Need to Fast?
Routine brain MRA generally does not require fasting.
However, if MRA is performed as part of a comprehensive health checkup, fasting may still be required because of other examinations in the same package.
The Bottom Line
Brain MRA is a non-invasive way to evaluate the arteries of the brain, particularly for intracranial aneurysms and arterial stenosis.
Routine screening is usually performed using non-contrast TOF MRA, which avoids both radiation and IV contrast.
Its value is greatest when there is a meaningful reason to evaluate cerebral vessels, particularly in people at increased risk of intracranial aneurysm. Routine aneurysm screening is not necessary for every healthy adult.
MRA also has limitations. Because TOF MRA depends on blood flow, slow or turbulent flow can sometimes mimic or exaggerate arterial stenosis, and very small vascular abnormalities may be difficult to characterize.
If MRA shows a suspicious aneurysm, significant stenosis, or an uncertain vascular abnormality, CTA may be used for more detailed anatomical evaluation.
The simplest way to distinguish the two examinations is:
Brain MRI looks primarily at brain tissue. Brain MRA looks primarily at the arteries.
When choosing a Korean health checkup package, make sure you know whether MRI, MRA, or both are included.
This article is intended for general educational purposes and does not replace individualized medical advice or diagnostic evaluation.