Ch 28 Thorax Principles Flashcards
The magnitude of atelectasis is related directly to the ______ of the patient
body mass
The pulmonary vessels in the right cranial lung lobe are much less conspicuous in a _____ lateral
right;
This is caused by the dorsal displacement of the right cranial lobe that occurs when the patient is in right lateral recumbency resulting in the right cranial lobar vessels being superimposed on the left cranial lobar vessels.
In the left lateral view, the two dorsal crura of the diaphragm _________.
deviate from each other
In the right lateral view, the two dorsal crura of the diaphragm ___________.
are more parallel
In which lateral projection does the CVC merge/silhouette with the diaphragm?
Right lateral
the dependent right crus will be cranial to the left crus because of pressure from abdominal contents, and therefore the caudal vena cava will silhouette, or merge, with the more cranial right crus that contains the caval hiatus.
The heart will appear slightly more round and the apex may be slightly elevated from the sternum in the _____ lateral view
Left
Caudal lobe pulmonary vessels are more conspicuous in ___ (projection); Why? 3 reasons
DV
(1) they are magnified
(2) they are oriented more perpendicular to the primary x-ray beam and therefore less distorted (3) there is less adjacent pulmonary atelectasis when the patient is in ventral recumbency
In which projection (VD or DV) does the diaphragm contact the heart?
DV, the ventral aspect displaces cranially, the heart is usually displaced slightly to the left
In which projection (DV or VD) is the heart appears more round?
DV, it stands more upright
Is leftward cardiac displacement in DV projections more pronounced in large dogs or small dogs?
large dogs (will not be as obvious in small dogs or cats)
Which kVp / mAs combination is used for thoracic rads?
high kVp
low mAs
What happens if you use a low kVP/ high mAs for thorax rads (with film screen system)?
The contrast of the image will be too high, and it will not be possible to assess the lung parenchyma adequately.
When should a grid be used?
For patients thicker than 10cm
B
Why is a grid used?
To remove scattered x-rays from the beam
A
D
high kVp, low mAs
C
C
D
A
B
A
D
