CT Scan vs MRI: Uses, Costs, and Key Differences (2025)

What Is the Difference Between a CT Scan and an MRI?

MRI brain scan images showing soft tissue contrast for diagnosing neurological conditions.

CT brain scan images highlighting skull and brain structures for trauma assessment.

A computed tomography (CT) scan and a magnetic resonance imaging (MRI) scan are two different imaging techniques used to visualise internal structures of the body, each suited to specific diagnostic needs.

The key differences between CT and MRI lie in their imaging methods, duration, suitability, and diagnostic applications.

Feature	CT Scan	MRI
Technology	X-rays	Magnetic fields and radio waves
Common Uses	Bones, lungs, trauma, bleeding	Brain, spinal cord, joints, soft tissues
Cost	Generally lower than MRI	Typically more expensive
Duration	Few minutes	30 – 60 minutes
Radiation Exposure	Yes	No
Not Suitable For	Pregnancy (due to radiation)	People with metal implants or pacemakers

What Is a CT Scan and How Does It Work?

CT scan machine in hospital imaging room used to diagnose injuries and conditions.

CT scan image showing abdominal and kidney structures during routine screening.

A CT scan works by using a rotating X-ray beam and digital processing to capture multiple images from different angles, which are then combined to provide detailed cross-sectional views of the body.

These images offer a clearer view than standard X-rays, especially for detecting injuries, infections, or abnormalities in bones and internal organs.

Because CT scans involve ionising radiation, they are typically used when the diagnostic benefit outweighs the associated risk. The procedure is quick, usually completed within 10 minutes.

The CT scan procedure involves:

Lying on a table that moves through a circular scanner. You will be asked to remove any metal objects beforehand.
The scanner rotates around you to take X-ray images from multiple angles. You may be asked to hold your breath briefly to reduce motion blur.

In some cases, a contrast dye may be injected into a vein to improve the visibility of blood vessels, organs, or abnormal tissue within the scanned area.

What Is a MRI Scan and How Does It Work?

Modern MRI machine in clinical setting prepared for soft tissue or brain imaging.

MRI spine scan showing lumbar vertebrae and soft tissue for back or nerve evaluation.

An MRI works by using a combination of strong magnetic fields and radiofrequency waves to generate detailed images of internal organs, soft tissues, and the nervous system.

Unlike CT scans, MRIs do not use ionising radiation, making them an ideal choice for repeated imaging in certain patients.

The procedure takes longer, often lasting 30 to 60 minutes, and involves lying still in a cylindrical scanner.

The MRI procedure involves:

Lying on a table that slides into a tube-shaped scanner. You will be asked to remove any metal objects beforehand.
The machine uses magnetic fields and radio waves to capture images. You must remain very still throughout the scan.

If contrast material is needed, it is usually injected into a vein to help differentiate between normal and abnormal tissues, such as tumours, inflammation, or blood supply to certain structures.

When Is a CT Scan Recommended?

A CT scan may be recommended for conditions involving bones, acute injuries, or when rapid imaging is necessary. It is especially useful for:

Evaluating fractures and bone disorders
Detecting internal bleeding or traumatic injuries
Identifying tumours, infections, or blood clots
Guiding biopsies and other image-assisted procedures

When Is an MRI Recommended?

An MRI is usually recommended when detailed images of soft tissues or the nervous system are needed. It is often used for:

Diagnosing brain and spinal cord conditions
Assessing joint and soft tissue injuries
Evaluating pelvic and abdominal organs
Monitoring tumours and tracking treatment response

Because of its ability to provide higher contrast resolution compared to CT, MRI is often preferred for complex conditions that require highly detailed anatomical imaging.

How Do You Prepare for a CT or MRI Scan?

Preparation for a CT or MRI scan depends on the type of scan and whether contrast material is required.

For CT scans:

You may be asked to fast for several hours before the scan, especially if intravenous contrast dye is required.

For MRI scans:

Fasting is generally not required, even if contrast is used, unless specified by the imaging provider.
Notify your provider if you have any metal implants, such as pacemakers, cochlear implants, or surgical clips. Also inform them if you are pregnant or experience claustrophobia.

For both scans:

Let your doctor know if you have any kidney conditions or a history of contrast allergies, as this may affect your suitability for contrast use.
Follow the specific instructions provided by your medical team to ensure a precise and safe imaging process.

What Are the Costs of CT and MRI Scans in Singapore?

CT scans are generally less costly than MRI scans in Singapore because of differences in imaging technology, scan duration, and equipment requirements.

At ATA Medical, we are a one-stop centre offering CT scans, MRI, ultrasound, and X-rays to support diagnosis and ongoing monitoring across various parts of the body. Our prices are as follows:

Test	Price*
Consultation	From $38.15
CT Scans
CT Calcium Score	$381.50
CT Lung	$403.30
CT Brain	$577.70
CT Temporal Bone	$577.70
CT Orbits	$577.70
CT Facial Bones	$577.70
CT Face	$577.70
CT Sinus	From $256.15
CT Neck	$577.70
CT Thorax	From $577.70
CT Abdomen	From $577.70
CT Liver (with contrast)	$1122.70
CT Pancreas (with contrast)	$1122.70
CT Kidneys (with contrast)	$1122.70
CT Pelvis	$577.70
CT KUB (kidney, ureter and bladder)	$381.50
CT Spine	From $577.70
CT Abdomen & Pelvis (CTAP)	$1199
CT Coronary Arteries (Includes Calcium Score)	$1329.80
CT Coronary & Carotid Angiogram	$2299.90
MRI
Spine	From $1035.50
Hand (per side)	$1035.50
Wrist (per side)	$1035.50
Forearm (per side)	$1035.50
Elbow (per side)	$1035.50
Shoulder (per side)	$1035.50
Foot (per side)	$1035.50
Knee (per side)	$1035.50
Thigh / Femur (per side)	$1035.50
Hip (per side)	$1035.50
Pelvis	From $1449.70
Brain	From $1068.20
Stroke Screen (includes MRA, COW & Carotids)	$1177.20
Neck / Nasopharynx / Oropharynx / Post Nasal Space	$1449.70
Abdomen (Kidney, Liver, Pancreas, Gallbladder & Spleen)	$1471.50
Rectum (with contrast)	$1471.50
Ultrasound
Ultrasound	From $43.60
X-ray
X-ray	From $49.05

*Prices are NETT and inclusive of GST.

Diagnostic imaging used to diagnose or treat medical conditions for yourself or your dependents is MediSave claimable, up to a limit of $300 per year. This does not apply to plain X-rays or scans that are claimable under other MediSave schemes, such as those for chronic conditions under the Chronic Disease Management Programme or for cancer treatment.

If you are looking for a more comprehensive assessment of your health, you may wish to consider our health screening packages, which can include a range of diagnostic scans.

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Female patient undergoing ultrasound scan procedure at ATA Medical Clinic.

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Female patient getting ready to undergo X-Ray procedure with a male staff assisting with the preparations.

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Frequently Asked Questions (FAQs)

CT scans involve exposure to ionising radiation, whereas MRI scans do not use any radiation. CT uses X-ray technology to produce images, which results in a measurable radiation dose, while MRI relies on magnetic fields and radio waves. The use of CT scans is considered appropriate when the diagnostic benefits outweigh the risks of radiation. If you are concerned, it is best to discuss with your doctor to help determine the most suitable imaging method for your condition.

Neither an MRI nor a CT scan typically causes hair loss, as the radiation dose from CT scans is not high enough to affect hair follicles and MRI does not use radiation. Hair loss is usually associated with repeated high-dose radiation therapy rather than diagnostic imaging. If you have concerns about cumulative imaging exposure, it is advisable to consult a medical professional.

CT scans are typically used first to assess for a haemorrhagic stroke because they are fast and effective at detecting acute bleeding in the brain. MRI may be performed later to provide more detailed information about brain tissue changes. If you or someone else is experiencing symptoms of a stroke such as sudden weakness, difficulty speaking, facial drooping, or vision changes, seek urgent medical attention immediately.

Ultrasound uses sound waves and is often used to image soft tissues in real time, such as during pregnancy or to examine organs like the liver and kidneys. CT uses X-rays and is preferred for viewing bones, internal bleeding, and injuries, while MRI uses magnetic fields and radio waves to capture detailed images of soft tissues like the brain, spine, and joints.

CT scans are more effective than MRI for detecting acute bleeding, lung conditions, and complex bone fractures, particularly in emergency settings. They also offer faster scan times and are better suited for patients who cannot remain still for long.

CT scan in Chinese is commonly referred to as “电脑断层扫描” (diànnǎo duàncéng sǎomiáo), which translates to “computerised tomography scan.” This term is widely used in Chinese-language medical settings to describe the imaging process that produces detailed cross-sectional views of the body.

Whether a CT scan or MRI is better depends on the clinical need, as each imaging method has different strengths. CT scans are often used for bones, trauma, and internal bleeding, while MRIs provide greater detail for soft tissues such as the brain, spinal cord, and joints. Your doctor can help determine which scan is more appropriate based on your symptoms and medical history.

An MRI can detect certain soft tissue conditions that a CT scan may not show clearly, including spinal cord abnormalities, ligament injuries, and small brain lesions. MRI is also more sensitive in identifying nerve inflammation and tumours in soft tissue.

You do not go into a full tunnel for a CT scan, but rather through a short, doughnut-shaped scanner that is open on both ends. This scanner is less confining than an MRI machine and is typically more comfortable for patients who are claustrophobic. The scan usually takes only a few minutes to complete.

CT scans involve exposure to ionising radiation, which may carry risks with repeated use, particularly in children or pregnant patients. They also offer less soft tissue detail compared to MRI. In some cases, the contrast dye used may cause allergic reactions or affect kidney function. It is advisable to consult a doctor about the potential risks to determine whether the benefits outweigh them for your specific medical needs.

Two disadvantages of MRI scans are longer scan times and limitations with metal implants. MRI procedures can take up to an hour and require patients to remain very still, which may be difficult for some individuals. Additionally, MRI is not suitable for people with certain implanted devices, such as pacemakers, cochlear implants, or some types of aneurysm clips. It is advisable to consult a doctor to confirm whether MRI is appropriate in your case.

A CT scan may be needed after an MRI if additional information is required, particularly for bone structures, lung conditions, or acute bleeding that MRI may not clearly reveal. The two scans often provide complementary insights that support a more complete diagnosis.

MRI generally provides more detailed images of soft tissues, while CT scans are better for visualising bones, lungs, and acute injuries such as bleeding or fractures. The choice depends on the area of the body being examined and the clinical concern. Your doctor can help determine which scan is more appropriate based on your symptoms and medical history.

CT scans are not ideal for detecting nerve damage, as they have limited ability to visualise nerves and soft tissue detail. MRI is typically preferred for evaluating nerve injuries, spinal cord abnormalities, and inflammation.

MRI is generally preferred for brain imaging because it provides higher contrast resolution for soft tissues and can detect abnormalities such as tumours, inflammation, and nerve damage with greater detail. CT scans are typically used in emergency settings to quickly assess trauma, bleeding, or stroke.

The cost of a CT scan in Singapore varies based on the area being scanned and whether contrast is required. At ATA Medical, CT scans typically range from $256.15 to $2299.90, with common scans like a CT Brain costing $577.70. All prices are NETT and inclusive of GST, excluding consultation fees. MediSave claims may apply for eligible medical conditions. Contact us for more information on pricing and coverage.

There is no fixed limit on the number of CT scans considered safe, but each scan contributes to cumulative radiation exposure. The decision to undergo multiple scans is based on clinical necessity, where the potential diagnostic benefit outweighs the associated risks. If you are concerned about frequent imaging or radiation exposure, it is best to discuss this with your doctor to evaluate the need and explore possible alternatives.

A CT scan is generally not uncomfortable and is completed within a few minutes while you lie still on a scanning table. Some individuals may feel mild discomfort from the contrast injection or experience anxiety in the scanning environment, but physical discomfort is usually minimal. If you have concerns about the procedure, it is best to discuss them with your doctor to help you understand what to expect and address any worries in advance.

Closing your eyes during a CT scan is not necessary, but many people do so to help themselves feel more relaxed. The scanner is open and not enclosed like an MRI machine, so claustrophobia is less common. You will be guided throughout the procedure, which is painless and typically completed within a few minutes.

You may be asked to change into a medical gown for a CT scan, especially if your clothing contains metal components that could interfere with the images. In some cases, if your clothing is loose-fitting and free of metal, you may be allowed to remain dressed. Instructions will be clearly provided throughout the procedure based on the area being scanned.