Difference between MRI and CT scan
What is MRI?
Magnetic resonance image is a medical imaging method. It used in the radiology laboratory to make images of physiological processes. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to create images of the body’s organs.
MRI does not include the use of X-rays or ionizing radiation, which distinguishes it from CT and PET scans. MRI is the medical application of Nuclear Magnetic Resonance.
Although the risks of ionizing radiation are now well controlled in most medical cases, MRI can still be seen as a better option than a CT scan. MRI is widely used in hospitals and clinics for medical diagnosis and follow-up of the disease without the body being exposed to radiation. MRI gives different information compared to CT.
MRI was originally called NMRI, but the “nuclear” was removed to avoid negative associations. Some nuclear nuclei can sense radioactive frequency when placed in an external magnetic field; The resulting enhanced spin polarization triggers the RF signal in the radio frequency coil and is thus detected.
Radiofrequency pulses stimulate atomic spin energy transition, and magnetic field gradients localize polarity in space. By changing the parameters of the pulse sequence, different contradictions between the tissues are formed based on the relaxation properties of the hydrogen atoms in it.
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While MRI is widely used in diagnostic medicine and biomedical research, it can also be used to create images of lifeless objects. MRI scans can produce a variety of chemical and physical data, along with detailed spatial images. The continued demand for MRI in health systems has led to concerns about cost effectiveness and over-diagnosis.
What is CT scan?
Computed tomography scan is a medical imaging technique. It use for the computer processed combinations of several x-ray measurements taken from different angles.
Its cross-sectional images are used in various medical disciplines for diagnostic and therapeutic purposes.
But, there are many other types of CT, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). X-ray tomography, the precursor of CT, is a form of radiography, with many other types of tomographic and non-tomographic radiography.
CT data can be manipulated to display different anatomical structures based on the ability to perceive the X-ray beam. Historically, modern scanners allow data to be reformatted on various planes, or as volumetric representations of structures, even if the generated images are in the axial or transverse plane, perpendicular to the body’s long axis. Although common in medicine, CT is also used in other fields such as nondestructive materials testing.
CT use has increased dramatically over the past two decades in many countries. Over 72 million scans were performed in the United States in 2007 and over 80 million in 2015. Low radiation doses are often used in many areas, such as research on renal colic.
Side effects from intravenous contrast, which are used in some studies, can increase the risk of developing kidney problems in the presence of pre-existing renal disease.