Basics of Radiology Flashcards
5 categories of radiographic studies
- plain film radiography (conventional radiograph)
- contrast-enhanced radiography
- tomography (conventional and computed)
- nuclear imaging
- magnetic resonance imaging
body part being imaged is exposed to electromagnetic radiation (x-rays), various tissues absorb differing amounts of the radiation, x-rays not absorbed by the body ionize the radiographic film and create an image
plain-film radiograph
plain-film radiograph usefulness/purpose
good for viewing bone and joint integrity and relationships; does not directly image soft tissue
plain-film radiograph exposure risk & cost
dependent upon anatomical area; single joint = minimal risk, lumbar spine series = moderate risk; $100-300
body part being imaged is injected with a contrast medium prior to taking a radiograph; purpose is to improve visualization by increasing the amount of contrast among various tissues
contrast-enhanced radiograph
contrast-enhanced radiograph usefulness/purpose
good for viewing joint and encapsulated soft tissue structures (i.e. joint capsule, vertebral disk, neural sheath, and tendon sheath)
contrast-enhanced radiograph exposure risk & cost
similar to plain-film radiograph + added risk due to invasive introduction of contrast medium; $700-$1200
arthrograph, myelograph, discograph
examples of contrast-enhanced radiographs
radiographic image shows one specific area or plane in focus with surrounding areas blurred; conventional or computed
tomography;
conventional = image created by moving x-ray tube and film in opposite directions, computed = uses computer to mathematically reconstruct an image, current tech actually allows reconstruction in 3D
tomography usefulness/purpose
use for imaging fractures, especially of irregular bone strucutres
tomography exposure risk & cost
moderate exposure risk; $1000-$1500
tissue specific radioactive drug is given intravenously, drug concentrates differently in normal and pathologic bones, film image records relative distribution of radioactive drug in bones; most common type = bone scan
nuclear imaging
nuclear imaging usefulness/purpose
useful for imaging areas of increased bone growth activity indicative of pathologies such as metastases, osteomyelitis, and fractures
nuclear imaging exposure risk & cost
high exposure risk; $800-$1000
pt placed in magnetic field and radio waves are pulsed at specific frequency, tissue nuclei absorb then release (resonate) energy produced by the radio frequency, radio receivers pick up the radio waves released by the various tissues; because tissues release differing amounts of energy, a well defined image is produced
magnetic resonance imaging (MRI)
MRI usefulness/purpose
primarily used to examine soft tissue for trauma and pathologies
MRI exposure risk & cost
no exposure risk to radiation; $1000+
when should plain film (conventional) radiographs be ordered?
key to appropriate requesting is through pt history & physical exam; generally used to confirm or rule out clinical impression of existing pathology or trauma
general indications for plain film radiograph ordering/requesting
- bony disruption is suspected
- articular surface involvement suspected
plain film radiographs viewing concepts
- radiodensity
- dimensions
- positioning v. projection (view)
refers to amount of x-ray beam absorbed by various tissues;
radiodensity
______ relationship exists between ______ of object/tissues and amount of _______ on x-ray film
- inverse; radiodensity; blackening
- greater thickness = greater density = less black
radiopaque
greater density/more radiodense (less black)
radiolucent
lesser density/less radiodense (more black)
