MRI
| MRI | CT SCAN | |
| How it works | An MRI uses a powerful magnet and radio waves to produce images of the internal parts of your body. | A CT machine sends X-ray beams through the body, taking many 2D pictures from various angles, which a computer later joins together to form a 3D image. |
| Machine shape | Doughnut-shaped machine with a hole in the middle, mostly closed on the other end. (Closed MRI, most powerful) | Doughnut-shaped machine with a hole in the middle, open on both sides. |
| Strength indicators | Check the magnet strength denoted by ‘T’ for Tesla. Today, a 3T MRI (closed MRI) is the most widely accepted MRI scanner that produces images of maximum clarity. | In CT machines, the greater the number of ‘slices’, the sharper the quality of the scan. For example, a 128 slice CT machine produces very clear images as compared to a lower slice CT scanner. |
| Purpose | An MRI scan is required when images need to be detailed. An MRI scan offers more soft tissue image and bone details than a CT scan. Especially in the case of strokes, tumours, etc. MRI scans show the difference between normal and abnormal tissue. | A CT scan is used when speed is important: for example, in the case of trauma and stroke. CT scans enable imaging of bone, soft tissue and blood vessels at the same time, but they are not as detailed as an MRI – for example, a CT scan can pinpoint size and location of tumours but does not show differences between normal and abnormal tissue. |
| Magnets and radiation | An MRI has no ionizing radiation since it works on magnetic fields and radio waves | Though a CT scan uses X-rays, its radiation dose is small enough to be negligible. However, CT scans may not be recommended for pregnant women or very small children. |
| Time taken | Average Duration: 7-20 minutes | Average Duration: 5-15 minutes |