|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|