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What is the Difference Between MRI and CT?

What is an MRI?

MRI stands for magnetic resonance imaging. An MRI is a special imaging modality that allows a doctor to see the soft tissue of any extremity or body part that needs to be examined. MRI machines are large, tubular magnets that you lie inside. While you are lying in the machine, the magnetic field temporarily moves the hydrogen atoms in your body. Radio waves are then used to make these atoms produce minute signals which can create an image of the interior of the body.

Even 3-D images can be produced by an MRI machine.

The MRI is mostly known to be using a strong kind of magnetic field as well as the radio waves for creating detailed images of the internal tissues as well as the organs. Existence of MRI brought about a revolution to the medical world. Since this procedure was discovered, the doctors as well as the researchers have known to see a refined technique for using MRI scans for assisting in various medical procedures as well as it also helps in the field of medical research.

The MRI scan basically makes use of the large magnet, the radio waves and the computer for creating a detailed kind of cross-functional image of the patient’s organs and well as the structures present within the body. The MRI scanner itself is known to resemble like a large tube wherein there is a table in the middle and it allows for the patient to slide into the tunnel once the patient lies on that table.

MRI scanning are different than the CT scans as well as the X-rays. The reason is because it does not make use of the ionizing radiation which can turn out to be potentially harmful for the patient. The MRI scan development has turned out to be a huge milestone in the field of medical since the doctors, the researchers as well as the scientist are now finding it easier to examine the inside structure of the human body accurately by using a non-invasive tool. Below are few of the examples wherein the MRI scanner is being used:

  • Patients suffering from certain kind of heart issues
  • Any kind of suspected abnormalities in the uterine in those women who are undergoing evaluation for infertility.
  • Any kind of abnormalities present in the spinal cord and the brain.
  • Disease concerning the liver or the abdominal organs.

What are MRI images used for?

Such images may include those of tendons, ligaments, bones, organs and blood vessels. It really is a great way of looking at soft tissue injuries, diseases and disorders, without having to open up the body to see what is going on inside. With these images, doctors can evaluate and diagnose a wide range of conditions including cancers, tumors, heart and vascular diseases, muscular and bone injuries and many more.  


What is a CT scan?

A computerized tomography scan, or CT scan, is a special type of X-ray which uses a computerized program to look at axial images of a person’s body part. The computer processing program combines a series of X-ray images that were taken at different angles to produce a cross-sectional image.

CT scan or also known as computerised tomography scans are basically a special type of X-rays which makes use of a computerised program for viewing at the axial images of the individual’s internal parts of the body. This computer processing program is known to combine a series of X-ray images which have been taken at various angles for producing a cross sectional image. These scans are done in the hospital and are often painless. The newer form of CT scan machines now takes less time for completing the procedure.

The entire procedure would normally take around thirty minutes. The shape of the CT scans is basically like a large doughnut standing on its side. The individual has to lie down on a narrow kind of motorised table that would slide through the opening of the tunnel. There would be use of straps and pillows for helping the individual to stay in a position. During the scanning of the head the table can be lifted with the help of a special cradle which would hold the head still.

While the table tends to move one into the scanner, the detectors as well as the X-ray tube would be rotating around the individual. Each of the rotation would yield multiple images of the thin slices of the body hence the individual may hear a constant buzzing or whirring sound. CT scans are mostly used for scanning the internal structures as well as viewing the density, shape, texture and size. They are also known to show the organs functioning, metabolic activity and blood vessels filling.

What are CT scans used for?

CT images are used to examine internal structures and view their shape, size, density and texture. They can even show organs functioning, blood vessels filling and metabolic activity. Since the scan shows such detail, doctors can use it to identify and diagnose a medical problem.

They can be used to diagnose an infection, locate an exact area of the body that needs to be reached, study blood vessels and identify tumors, cysts or other masses.  


  • CT images typically look at the head, abdomen, spine, pelvis and chest.
  • MRI images usually are used on soft tissues, tendons, ligaments and joints.
  • CT scans use X-rays and ionizing radiation, while MRI images use X-rays and magnets.
  • A CT scan can take just five minutes, and an MRI might take 30 minutes to complete.
  • CT scans carry greater risks than MRIs due to the radiation exposure. 
  • MRI machines are more closed in as compared to CT machines. Therefore, claustrophobics prefer a CT scan over an MRI.
  • Since MRIs use a magnetic force, you cannot get one if you have a metal implant. 
  • If you are heavier than 450 pounds, you might not be able to fit in a CT scanner. If you weigh more than 350 pounds, you may be too large for an MRI machine. 
  • Getting a CT scan is not as expensive as getting an MRI is.
  • CT machines were invented in 1971, while MRI machines were invented 10 years later, in 1981.