CT Scan VS MRI: Which Is Better For Diagnosis?

When it comes to diagnosis of heart related issues, getting the right imaging test done is extremely crucial. Both MRI (Magnetic resonance imaging) and CT (Computed Tomography) scans are recommended by medical professionals as they provide us with important information about your heart health. However, they are different in many ways. This article will not only tap into the differences between MRI and CT scan, but will also dive deeper into their risks and benefits.

To get a better understanding of this, we reached out to our experts, Dr Sanjay Bhat, Senior Consultant - Interventional Cardiology, Aster CMI Hospital, Bangalore and Dr VP Sharma, Director and Senior Consultant Cardiology, Fortis Hospital Jalandhar, Punjab.

CT Scan Vs MRI: Which Is Better?

“Cardiac CT scan and Cardiac MRI are two advanced imaging tests used to look at the heart, but they work in different ways and are used for different purposes,” shares Dr Bhat. Which one is better though? Shedding light on this, he says, “One is not always better than the other, and the choice depends on the patient’s condition. A Cardiac CT scan uses X-rays to create detailed pictures of the heart and blood vessels. It is fast and very useful to check for blockages or narrowing in the coronary arteries. Doctors often use it to detect calcium deposits and assess the risk of heart disease. It is also helpful in emergency situations because it takes only a few minutes.”

The expert adds, “A Cardiac MRI uses strong magnets and radio waves to create detailed images of the heart. It does not use radiation, which makes it safer for repeated use. Cardiac MRI is better for looking at the heart muscles, structure, and function. It helps diagnose conditions like heart muscle damage, inflammation, scarring, and certain types of heart failure. In simple terms, Cardiac CT is best for checking blood vessels and blockages, while Cardiac MRI is better for understanding the heart muscle and its function.”

ALSO READ - How Many CT Scans Are Safe? Expert Explains The Risks And Benefits

What Are MRIs Used For?

Speaking about the use of MRI, Dr Sharma says, “It  is best used for conditions like cardiomyopathy, myocarditis, checking heart muscle viability before revascularisation, and complex congenital heart diseases. However, it takes longer, may not be suitable for some patients with implanted devices, and can be uncomfortable for some people.” 

The expert adds, “Cardiac MRI uses no radiation and excels at detailed assessment of heart muscle, chambers, valves, blood flow and tissue characterisation (inflammation, fibrosis, viability), with very high spatial resolution and reproducible measurements of function.”

According to the Cleveland Clinic, MRIs are used for the following:

• Tissue
• Nerves
• Organs
• Spine and spinal cord
• Blood vessels
• Lymph nodes
• Brain
• Joints

What Are CT Scans Used For?

Explaining the use of CT scan, Dr Sharma says, “Cardiac CT angiography is usually preferred when we need a fast and non‑invasive look at the coronary arteries to rule out significant blockages. It uses X‑rays and iodinated contrast, where radiation exposure and kidney function are considered, and image quality is best with a slow, regular heart rate. However, heavy calcium or stents can limit the accuracy of the result.”

As per the Cleveland Clinic, CT scans are used to look at the following:

• Bones
• Stones
• Blood
• Organs
• Lungs
• Cancer stages
• Abdominal emergencies

Are CT scans risky?A 2025 study, published in JAMA Internal Medicine journal, studied whether future cancers could result from radiation exposure from annual computed tomography (CT) examinations. The findings took note of 93 million CT examinations, which were  performed in 62 million patients in 2023. It is projected to result in approximately 1,03,000 future cancers. The findings noted that if current radiation dosing and utilisation practices continue, CT-associated cancers may eventually account for 5% of all new cancer diagnoses annually. 

How To Choose Between CT Scan And MRI?

If you are wondering how to make the right choice, Dr Bhat lists down some points to help:

• Each test has its advantages and limits. CT scans are quick but involve radiation exposure, while MRI scans take longer and may not be suitable for people with certain metal implants or severe claustrophobia.
• Doctors decide which test is needed based on symptoms, medical history, and what they want to find.
• Sometimes, both tests may be used for a complete evaluation. 

“In practice, we often start with CT when coronary anatomy is the main concern and use MRI when muscle disease, function or scarring are the key questions,” says Dr Sharma.

MRI Vs CT Scan Comparison:

Conclusion

Both Cardiac CT and Cardiac MRI are valuable tools, and the “better” option depends on the specific heart problem being investigated. To summarise, Cardiac CT is best for checking blood vessels and blockages, while Cardiac MRI is better for understanding the heart muscle and its function.

ALSO READ - Eye Scans Can Reveal Heart Disease Risk and Ageing Speed, Claims Study — But What Does an Expert Say?