Many patients traditionally turn first to ultrasound (US) when diagnostic imaging is needed. This method is familiar, widely available, and safe. However, ultrasound has certain limitations — it does not provide a true three-dimensional image like CT. Ultrasound displays images in one or two planes, while Computed Tomography allows the physician to examine the area of interest from all angles with exceptionally high accuracy and image quality, significantly increasing the chances of making the correct diagnosis.

CT and X-ray

Both CT and conventional X-ray are based on the use of ionizing radiation. A CT scanner is sometimes referred to as a “large X-ray machine.” Although the underlying principle is similar, CT is many times more informative. For example, standard chest X-rays may be less effective in detecting early viral pneumonia, including COVID-19, while CT can reveal even subtle changes in lung tissue.

Differences Between CT and MRI

The main difference between CT and Magnetic Resonance Imaging (MRI) lies in the type of energy used to create images. MRI uses electromagnetic fields and radio waves, so it does not expose the patient to ionizing radiation. For this reason, MRI is considered a very safe diagnostic method and can be used in many patients, including children and some pregnant women when clinically indicated.

A significant disadvantage of MRI compared to CT is the duration of the examination. MRI usually takes 20–60 minutes, whereas CT generally takes 5–20 minutes. This may be uncomfortable for patients with claustrophobia. MRI is also contraindicated in individuals with certain pacemakers, neurostimulators, and some metal implants or foreign bodies.

Which Is Better: CT or MRI?

CT and MRI are fundamentally different methods, each with its own strengths.

CT is particularly effective for oncologic screening, evaluation of the chest and abdominal organs, lungs, bones, trauma, and hemorrhage.

MRI is especially useful for examining the brain and spinal cord, pelvic organs, blood vessels, joints, and soft tissues.

The choice between CT and MRI depends on the clinical situation and should be determined by a physician.