Medical Imaging Flashcards
What does Medical Imaging refer to?
Techniques and processes used to create images of the human body. They allow visualization of structures inside the body, to increase the precision of diagnosis.
List common medical imaging procedures.
Radiography, Magnetic Resonance Imaging (MRI), Coronary (cardiac) Computed Tomography Angiography (CCTA), Computed Tomography (CT), Ultrasound, Radionuclide Scanning, Endoscopy, PET scan.
How is a radiograph taken?
Single barrage of x-rays passes through the body, to produce an image of interior structures. [They are inexpensive, quick, simple]
What contrast x-rays used to view?
Blood vessels (angiography), the urinary system (intravenous urography) and the gastrointestinal tract (barium contrast x-ray)
How is a Magnetic Resonance Imaging (MRI) taken?
The body is exposed to a high-energy magnetic field, which causes protons in body fluids and tissues to arrange themselves in relation to the field. Pulse of radio waves are colour-coded and read.
Why are MRI’s used?
They’re relatively safe, used to detect abnormal tissues like tumors, artery-clogging fatty plaques, brain abnormalities, measuring blood flow, and detecting a variety of musculoskeletal, liver and kidney disorders.
What does CT stand for?
Computed Tomography.
How is a CT taken?
An X-ray beam traces an arc at multiple angles around a section of the body. The resulting transverse section of the body, CT scan, is shown on a video monitor.
Why is a CT used?
To visualize soft tissues and organs with much more detail than conventional radiographs.
What does CCTA stand for?
Coronary Computed Tomography Angiography
How is a CCTA taken?
An iodine-containing contrast medium is injected into a vein and a beta-blocker is given to decrease heart rate. Numerous x-ray beams trace an arc around the heart and a scanner detects the beams and transmits them for a 3D image.
Why is a CCTA used?
To determine whether there are any coronary artery blockages.
How is an ultrasound taken?
High frequency sound waves produced by a handheld wand reflect off body tissues and are detected by the same instrument.
Why is an ultrasound used?
It’s safe, non-invasive, painless, and uses no dyes. Most commonly used to visualize the foetus during pregnancy. Also used to observe size, location, actions of organs and blood flow through blood vessels.
How is a radionuclide scan taken?
Radioactive substance is introduced intravenously into the body and carried to the tissue to be imaged. Gamma rays are emitted and detected by a camera.
