3.1.5. Introduction to Radiology and Chest Imaging Flashcards
What is opacity?
Opacity: any area with increased attenuation, therefore more opaque to X-rays, producing a whiter/brighter area on the image. (on a photographic negative)
Define “line”
Line: a visible opacity that is contrasted against more lucent areas on BOTH sides. (also the reverse)
Define “edge”
Edge: a boundary or demarcation between two different densities, such that the transition is sharp
Define “lucency”
Lucency: an area more transparent to X-rays, producing a darker area on the image.
Define “density”
Density: the quality of an object that blocks light (on a film) or X-rays (on a radiograph). Has been used as a synonym for “opacity” – but not as correct.
Define “silhouette sign”
Silhouette sign: the LOSS of a normal anatomic border by the apposition of a normal structure or abnormal lesion of similar opacity
What are some identifying factors of a pneumothorax (on imaging)?
What is an air bronchogram?
Fluid or soft tissue surrounding a bronchus where air should be.
How do you check for correct patient positioning on an image?
Why is this important?
Check to see if the spinous process is midway between the clavicles. If it is off-center, the patient is not positioned correctly. This can distort imaging and make things look larger or smaller than they actually are (leading to potential misdiagnoses).
Geometric magnification makes the heart shadow appear larger on which two types of imaging?
The heart shadow appears larger on AP and on portable ICU radiographs vs PA and standard machines. Keep this in mind so you don’t accidentally misdiagnose a normal heart as enlarged.
