Intro To Radiology Flashcards
What color are dense objects?
White, radio-opaque
What color are non-dense objects?
Black (transparent), radio-lucent
What are the structures on gray scale?
Air, fat, blood, muscle, bone, lead
Black White
What are dx imaging used for?
-localize an anatomic problem
-to ID the tissue involved
-to ID the nature of the tissue damage
-direct treatment
Types of imaging
X-ray, CT, MRI, ultrasound, nuclear imaging
What is x-ray?
Form of electromagnetic radiation
What is the primary value of routine radiography?
Documenting bony defects
How many and what type of views are used for dx radiology for musculoskeletal pathology?
-Minimum of two views perpendicular to each other
-Additional oblique views often considered
X-ray advantages and disadvantages
Advantages: quick, inexpensive, ideal for bony changes
Disadvantages: doesn’t show soft tissue changes, radiation exposure
What does CT scan stand for?
Computerized (axial) tomography
What is a CT scan?
Moving x-ray; provides detailed planar images by progressive visual
Advantages of CT
-cross sectional images
-can enhance w/ contrast
-better sensitivity than x-ray
-ok w/ metal
-fast
Disadvantages of CT
-high radiation exposure
-less sensitive than MRI
What does MRI stand for?
Magnetic resonance imaging
What is MRI used for?
No radiation involved and ideal for soft tissue contrasts
What does a MRI do and how does it work?
-powerful magnetic field to pt
-detects rate of magnetization and demagnetization
-produces “slice” images in any plane
Advantages of MRI
-grey scale doesn’t apply, any structure can be highlighted
-no radiation exposure involved
-high sensitivity to slight tissue differences
-can image in several planes
-can image through bone
Disadvantages of MRI
-cost
-time lying still
-limited tube size
-can’t use metal
-can be too sensitive/not specific
-not good for bone/calcified tissue
What is ultrasound? What does it produce?
-picks up and examines timing and amplitude of reflections for echo examines frequency change for doppler
-produces a 2D image in real time
Advantages of ultrasound?
-biologically harmless
-records and displays motion
-requires no contrast
-portable
-distinguishes solid from fluid
Disadvantages of ultrasound
-does not penetrate bone well
-doesn’t go through air/gas
-skill dependent
What does ultrasound image well?
Fetus, children, abdominal organs, aorta, blood flow
What is another name for bone scan?
Skeletal scintigraphy
What is a bone scan used for?
-help dx problems w/ bones
-tool of nuclear medicine
Bone scan used dx-ly in suspicion of
-metastatic disease
-arthritis
-stress fracture
-osteomyelitis
-loosening of implants
-multiple trauma
How does a bone scan work?
-pt given radioisotope into veins
-takes 2-4 hrs for radioactive substance to gravitate to areas of bone damage
-dark spots = damage
What is nuclear imaging?
Non-invasive procedure that uses injected radioactive material and PET scanner, CT scan or MRI
What does nuclear imaging image well?
-thyroid masses**
-bone metastases**
-lung circulation and ventilation**
-cancer, GI disease, endocrine disease
What to look for in review of medical record and work ups to date
-types of tests done
-normal study or abnormalities reported (structure, location, severity)
-decision making “do reported findings correlate w/ clinical s/s?”
