Chapter 28 - Thorax Principles Flashcards
(28 cards)
Most likely DDx?
Remodeling of the costochondral junction
Which is the VD? and DV?
A.VD B.DV
In the DV radiograph, the diaphragm is displaced cranially where it contacts the heart and pushes it into the left hemithorax. The cardiac silhouette is also smaller and rounder, because it is more upright in the thoracic cavity. In a DV view, the cranial excursion of the diaphragm also
impinges on the territory of the accessory lung lobe and interferes with the evaluation of that region.
Which is the LL? and RL?
A. LL B. RL
In the left lateral view, the cardiac silhouette will
usually appear slightly rounder, and there will be some slight separation of the cardiac apex from the sternum (white arrows in A).
Which is the VD? and DV?
A.VD B.DV
The caudal lobe pulmonary
vessels (black arrows) are more conspicuous in the DV view than in the VD
How is obtained low contrast image in the thorax?
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
