My brother has a stroke last year, we took him to the hospital and he was subjected to an MRI scan. It showed the part of his brain where a blood vessel burst, causing the stroke.
A few years before, the usual tool used in diagnosing medical problems of the body’s internal organs, is the Computed Tomography scan or CT scan. Today, people can choose which of the two they want to use. Both machines are used to diagnose any medical condition they have, showing slices of the patient.
Computed Tomography (CT)
CT scan is a specialized type of X-ray machine. It combines X-ray technology with computer technology which makes it easier for doctors to see problems inside the body. A patient is made to lie down on a table that slides into a circular opening. An X-ray tube then rotates around the patient and the data is collected in a computer.
It uses digital geometry processing to generate 3D images of the organs inside the body from the X-ray images collected. CT scan involves windowing, a process that manipulates data to show body structures based on their ability to block X-ray beams.
Originally, the collected images were of the axial and transverse planes but modern scanners can now allow these data to be reformatted in various planes to see problems better.
A CT scan can be risky because it involves radiation and needs the use of contrast agents made from iodine which can be absorbed by abnormal tissues in the body. It is the cheaper alternative though.
Aside from its medical uses, it is also being used in other fields like archeology and nondestructive materials testing.
Magnetic Resonance Imaging (MRI)
MRI is a medical imaging technique that uses magnets and radio waves to create images of internal body structures. The process involves having the patient lie on a table that is inserted into a long cylinder which is a magnet.
This magnetic field then aligns the hydrogen atoms in cells of the body and collects the signals from these atoms through an antenna. It uses radio frequency fields to send signals and record information which are then converted into images of the scanned parts of the body. The images are more detailed than the images produced by a CT scan but MRI is not very good at bone scans.
The magnetic field and radio waves can change the contrast in the images to highlight different tissues of the body. The contrast agents used are not from iodine, so it is safer to use and the imaging plane can be changed from top to bottom, front and back.
Summary:
1. CT scan uses X-ray and computer technology, while MRI uses magnetic fields and radio waves.
2. CT scan is cheaper than MRI scan.
3. CT scan uses iodine based contrast agents, while MRI does not.
4. CT scan is good at bone scans, while MRI is not.
5. MRI produces images that are more detailed than images produced with a CT scan.
6. MRI allows every area of the body to be seen at various planes, while CT does not.