Conditions and Treatment Flashcards
(49 cards)
Error rate in interpretation
As high as 20-40%
Errors of Observation
Doesn’t look like it’s there
Errors of Interpretation
Missed something
True Positive
Test detects something that is really there
False Positive
Test detects something that is not really there
True Negative
Test detects nothing, and nothing is there
False Negative
Test detects nothing, but there is something there
Sensitivity
Refers to test’s ability to identify a true positive
“SPOUT”
HIV blood test - very sensitive
Specificity
Refers to test’s ability to identify a true negative
“SPIN”
Home pregnancy tests - very specific
Radiograph
First-order diagnostic modality
Named for the beam direction relative to patient and patient’s position
Radiograph Advantages
Time/cost efficient
Low risk
Radiograph Disadvantages
May be normal although pathology exists
Attenuation
Reduced strength or density of the x-ray beam as it passes through a medium
Permeability
Ability of the x-ray beam to pass through substance to reach the film plate
Radiodensity
X-ray absorption capacity, based on substance’s composition, density, and thickness
Radiograph Image Quality
At least two views, ideally at 90 degree angle to each other, are necessary to visualize an object in three dimensions
Density
Amount of blackening on the radiograph dependent on distance, time, and current
Contrast
Differences between adjacent tissue densities
Detail
“Sharpness/Resolution”
Maximized by positioning patient so structure of interest is closest to film plate
Distortion
Occurs due to distance between beam source, patient, and image receptor, and from alignment and positioning issues
Foreshortening
Image appears shorter and wider than the actual object or structure
Magnification
Objects or structures further from the film appear larger than closer points
ABCs of Radiology
Alignment
Bone Density
Cartilage
Soft Tissue
Alignment
Gross bone size
Shape and contour of cortical outline
Joint position/alignment
