Thorax Part 1 Flashcards
what is the silhouette sign?
two structures of the same radiographic opacity that are in direct contact with each other lose their margins and cannot be seen as separate entities
whenever you see fluid where there should not be any, it’s probably going to be: ___________________________
blood
pus
water
where does gas where it should not be come from?
communication with outside world
communication with a structure that normally has gas in it
gas forming organisms
why do we take thoracic radiographs?
rule in/out causes of respiratory signs
investigate suspected cardiac disease
screen for metastatic disease
screen patients prior to anesthesia
evaluate patients who have undergone trauma
what technique do we use for thoracic radiographs?
high kVp technique
minimize exposure time
take radiographs at peak inspiration
use a grid if patient is thicker than 10cm
is right lateral better for assessing changes in the left or right lung lobes?
left lung lobes
how can you tell a lateral thoracic view is right lateral?
heart is “egg shaped”
diaphragmatic crura parallel to each other
right crus more cranial
better for assessing left lung lobes
how can you tell a lateral thoracic view is left lateral?
heart rounded
diaphragmatic crura diverge
left crus more cranial
better for assessing changes in right lung lobes
what differentiates a dorsoventral view from a ventrodorsal view?
heart position more consistent
diaphragm has one dome (cupula)
what differentiates a ventrodorsal view from a dorsoventral view?
heart “flops” and may look elongated
diaphragm has three domes (cupula and two crura)
why do we take both lateral views with a thoracic study?
dependent lung collapses
collapsed lung hides soft tissue opacity nodules
opposite lateral: aerated lung, provides contrast
what are some special views with thoracic radiographs?
oblique views
horizontal beam views
why would we take oblique views?
highlight thoracic wall masses
why would we perform horizontal beam views of the thorax?
diaphragmatic hernia
small volumes of pneumothorax
do we take VD or DV views of large animals?
no, only lateral views taken
not even young foals
where do you put the lung of interest when taking radiographs of a large animal?
close to the plate
what happens with pleural effusion and a pneumothorax in large animals on radiographs?
pleural effusion will fall
pneumothorax will rise
what are some thoracic contrast procedures?
esophagography
angiography
celiography
what should you evaluate when evaluating the thorax?
extrathoracic structures
diaphragm
mediastinum
pleural space
lungs, including pulmonary vasculature
cardiac silhouette
what extrathoracic structures should you check on a set of thoracic radiographs?
caudal neck
thoracic limbs
cranial abdomen
thoracic wall
what are some thoracic wall abnormalities?
congenital abnormalities
trauma
masses
why is a flail chest a problem?
can cause trauma to the lungs
what are thoracic wall masses recognized by?
extrapleural sign: intact parietal pleeura contains the mass, mass will indent the lung
what causes a flail chest?
segmental fractures of adjacent ribs
what can be seen on thoracic radiographs that would indicate a diaphragmatic hernia?
inability to clearly identify the diaphragm
displacement or lack of organs in the abdominal cavity
visualization of organs in the thoracic cavity
what can hamper your ability to identify a diaphragmatic hernia?
concurrent pleural effusion
what is a peritoneal-pericardial diaphragmatic hernia?
abdominal contents in pericardial sac
how can you identify a peritoneal-pericardial diaphragmatic hernia?
globoid cardiac silhouette
central/ventral diaphragm not clear
what is a hiatal hernia?
stomach coming through esophageal hiatus
what are the types of hiatal hernia?
sliding axial
GE intussusception
paraesophageal
where does the mediastinum extend between?
thoracic inlet to diaphragm
spine to sternum
what does the mediastinum consist of?
two layers of mediastinal pleura and the space between them
what structures are normally seen in the mediastinum?
trachea
heart
aorta
caudal vena cava
fat
what structures are occasionally seen in the mediastinum?
gas in esophageal lumen: aerophagia
thymus: normal if dog <1year
what are some structures that are not normally seen in the mediastinum?
cranial vena cava, brachiocephalic trunk
lymph nodes
outer surface of trachea and esophagus
what does the sternal lymph node drain?
pleural space
chest wall
abdomen
if you see a big sternal lymph node, what should you do?
look for a problem in the abdomen
what lymph nodes can be seen on thoracic radiographs (not normal)?
tracheobronchial aka hilar
sternal
tracheal
what does hilar lymphadenopathy look like?
ill-defined soft tissue opacity surrounding the carina on the lateral view
where bronchi come together on the DV view
what are some mediastinal abnormalities?
pneumomediastinum
mediastinal masses
mediastinal effusion
mediastinal shift
how can you recognize a pneumomediastinum?
increased visualization of mediastinal structures
where can gas dissect into from a pneumomediastinum?
subcutaneous tissues
retroperitoneal space
the cranial mediastinum should be no wider than __________________________ on the DV or VD view
twice the width of the spine
what breeds like to deposit fat in their mediastinum?
brachycephalic breeds
what is mediastinal shift?
mediastinum is shifted to one side on thee DV or VD radiograph
what is mediastinal shift recognized by?
displacement of the cardiac silhouette
what can mediastinal shift be due to?
collapse of lung
increased volume of a lung/hemothorax
mass
how can you recognize mediastinal fluid?
decreased visualization of mediastinal structures
diffuse widening of the mediastinum
what can mediastinal fluid be mistaken for on the lateral view?
pleural effusion or pulmonary disease
where does the esophagus live on the lateral view?
dorsal to the intrathoracic trachea
between aorta and caudal vena cava
where is the esophagus on a DV view?
slightly to the left of midline
what are some esophageal abnormalities?
esophageal motility disorder
vascular ring anomaly
esophageal mass
esophageal foreign body/choke
what is esophageal motility disorder?
decreased ability of the esophagus to propel food/water into the stomach
can you diagnose esophageal motility disorder if there is no food or water present?
no
does esophageal dilation mean the patient has a motility disorder?
not necessarily
could be aerophagia
when can ingesta be in the esophagus?
shortly after eaten (20 seconds)
in bolus form: 1 or 2 swallows’ worth
how do we diagnose esophageal motility disorder?
esophagography
if food/fluid is present in esophagus and not in bolus form: diagnostic
how can you perform an esophagography?
give barium liquid, paste and paste mixed with food
watch under fluoro or take rads after dog swallows
what is vascular ring anomaly usually due to?
persistent right aortic arch
what wraps around the esophagus in a vascular ring anomaly?
remnant of ductus arteriosus
when does an animal with a vascular ring anomaly start to show signs?
after it is weaned: regurgitating when changed to solids
what can chronic packing of food in the esophagus in vascular ring anomaly lead to?
pulsion diverticulum
