CT scan vs MRI – Procedure, Risks & Side Effects

mri machine

MRI uses Radio waves and CT scan use X-rays to diagnose the disease. In CT scan vs MRI, MRI is more preferable because it gives more details than a CT scan.

To understand CT scan vs MRI, firstly let’s know a little about these both. Computed Tomography Scan or CT scan is an imaging procedure used by the medical practitioners. The procedure requires a combination of many X-ray measurements taken from different angles.

ct scan vs mri
MRI Machine

The computer-processed images create a cross-sectional view or virtual slices of an object or body part scanned. On the contrary, the MRI is the Magnetic Resonance Imaging technique. This captures the anatomy and physiological processes of the human body.

People usually generalize a CT scan vs MRI as the imaging tool. but in actual both the techniques have different procedures and techniques to give the result. Moreover, they solve different purposes but people generalize the CT scan vs MRI as the imaging tool. In actual they are far different from each other, so be ready to understand and know everything about CT scan vs MRI.

What is CT Scan?

A computerized tomography produces the image of organs and body parts with the combination of X-ray images and computer processing. The combination creates cross-sectional images of the bones, blood vessels and soft tissues of the body.

Why CT Scan vs MRI

The doctors prescribe CT scan generally for following problems:

Why CT Scan
Hand Injuries
  • Detecting internal injuries and bleeding, if any.
  • To diagnose the disorder in muscle and bone, like fractures and tumours.
  • For examining the impact or effectiveness of certain treatments like Cancer.
  • Guiding the procedure of surgery, biopsy or radiation therapy depending upon the symptoms.
  • To detect the disease such as cancer, heart lungs and liver diseases.
  • It helps in locating the exact position of tumour, infection or blood clot.

Risks and Side Effects of CT scan vs MRI

CT scan produces ionizing radiation, which is comparatively greater than the simple X-ray because it captures detailed information. The low doses of radiation have not much longer harm but the much higher doses create a potential risk of harm to the body. Doctors use the level of dose depending upon the disease and requirement of the scanning. So, you must consult your doctor about the benefits and risk associated with your CT scan.

Procedure of CT scanning

CT scanner has a shape like a large doughnut; it requires the patient to lie on a narrow motorized table. The table will slide in the tunnel through the opening. In the case of head scanning, the table has the special cradle to hold the head still. Otherwise, straps and pillows can work to stay in the position.

Once the table moved in the tunnel and placed in the right position. The detector and X-ray tube starts functioning and rotates around the patient to yield several images of the human body. You must not panic during the procedure, it’s normal if you hear the whirring and buzzing noises. You can also ask technologists if there is an issue, they could be hearing you during the procedure.

After the procedure, you may require to take some precautions and have plenty of fluids in your diet to remove contrast from the kidney and you will be back to your normal routine.

There are some factors, a patient must notify the doctor or technologist before the CT scan vs MRI, such as

  • Pregnancy: You must disclose your pregnancy because radiations from the CT scan vs MRI could harm your baby. So, in that case, a doctor will prescribe any other test.
  • Diabetes: You must consult your doctor about the impact of CT scan on you if you are a diabetic patient.
  • Skin Issues: CT scan has very less impact on this aspect, but if you are allergic to any contrast material. It could lead to a life-threatening reaction.

What is MRI?

MRI scanners use magnetic fields, gradients and radio waves for imaging of the organ or body part. MRI is an application of Nuclear Magnetic Resonance leading in the medical industry. As in the CT scan, it does not require X-rays or ionizing radiations.

Why to Choose MRI vs CT scan?

The process of scanning through MRI is painless, the scanner or machine looks like a tube. This surrounds by a giant circular magnet and having movable bed inside. The patient requires to lie down on the bed and the technician inserts the bed into the magnet.

The magnet around the tube creates a strong field to align protons of hydrogen atoms that are further exposed to a beam of radio waves. The waves spin the protons of the body and create a faint signal, so the scanner detects it and results in the production of an image by the computer processor.

MRI scanner works on very detailed scanning and image capturing, which can show very tiny changes in the structure of the body. That is why doctors prescribe it after the other tests fail to provide exact information or problem in the patient’s body.

MRI for Brain and Spinal Cord

MRI for Brain and Spinal Cord
Spinal Cord’s MRI
  • Blood vessel damage
  • Trauma: The scanner is capable to detect swelling or bleeding in the brain caused by trauma.
  • Injury or tumours in the Brain
  • Tumours/ inflammation of the spine

MRI for Heart and Blood Vessels

Heart and Blood Vessels
MRI for Heart and Blood Vessels
  • Blockage in blood vessels
  • Damage caused by a heart attack
  • Heart structure problems
  • Other Heart diseases

MRI for Bones and Joints provides knowledge about:

  • Infections in Bones.
  • Cancer
  • Joint damages
  • Disc problems
  • Low Back or Neck pain problems

MRI to Examine Other Human Organs, such as:

  • Breast
  • Liver
  • Kidneys
  • Ovaries
  • Pancreas
  • Prostate

Other than these, doctors prescribe MRI to get exact information for glands and organs within the abdomen, the structure of the joints, soft tissues and bones.

Side Effects of MRI  vs CT scan

There are no specific known side effects of the Magnetic Resonance Imaging because it is in use to avoid the radiation exposure of X-ray. But there are some precautions to keep in mind before MRI, as it can distort the image obtained by the scanner and the accurate abnormality couldn’t be found. So, the precautions are:

Side Effects of MRI  vs CT scan

The Patient must notify its physician prior to the examination, about

  • Pregnancy
  • Any metallic materials within the body
  • Metallic Chips or material
  • Surgical clips
  • Foreign material, which means any artificial joints, bone plates or prosthetic devices placed in the body.

MRI could not be performed on patients having the following problems because magnetic rays can effect.

  • Heart Pacemakers
  • Metal Implants
  • Metal Clips or Chips used in or around the eyes.
  • Recently had any surgery.

Which is Better, CT scan vs MRI

Now, it must be easy for you to understand the major difference between a CT scan vs MRI. The latter uses Radio waves and the former use X-rays to capture the image of the human body. Both have less risk on the human body but are also comparable in terms of higher and lesser risk imposed.

In conclusion, the choice of these two depends only upon the requirement and disease to be detected. The doctors generally prescribe to have a CT scan before the MRI. If the problem is not detected in any other examination or CT scans, then MRI can provide information about tiny factors in the human body.


Q.1  Which is safer MRI or CT Scan?
Ans. MRI is safer than CT scan because the CT scan uses X-rays, which relates to the causes of cancer. Though there is no exact record to prove this.

Q.2  What MRI shows and CT Scan does not?
Ans.  MRI provides the detail information about every organ and even tiny compounds of the human body as CT scan gives a quick diagnosis.

Q.3  Which is more expensive CT scan vs MRI?
Ans.MRI costs almost a double amount requires to get a diagnosis with CT scan.

Q.4  Is cancer detectable by MRI?
Ans. Yes, MRI can provide information about cancer and tumours in the human body. Even doctors use this to find the impact or effectiveness of treatments given to cancer patients.

Q.5  How should I get prepared for a CT scan or MRI?
Ans. One must have plenty of fluids before and after the test. It helps in removing the impact of the procedure on the body.

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