Cardiac Radiographs Flashcards
are cardiac chambers visible on radiographs
no - use knowledge of anatomy
in lateral view - where is the right atrium and ventricle
RA: cranial and dorsal
RV: cranial and ventral
in lateral view - where is the left atrium and ventricle
LA: caudal and dorsal
LV: caudal and ventral
in DV view - where is the right atrium and ventricle
RA: right cranial
RV: right caudal
in DV view - where is the left atrium and ventricle
LA: left caudal
LV: left caudal - pokes out from LA caudally
in DV view - where are the great vessels
left cranial
cardiac clock - DV
11 to 1: aorta
1 to 2: pulmonary trunk
2 to 3: left atrium
3 to 5: left ventricle
5 to 9: right ventricle
9 to 11: right atrium
cardiac clock - lateral
12 to 3: left atrium
3 to 5: left ventricle
5 to 8: right ventricle
8 to 10: right atrium
10 to 12: great vessels
is the left or right ventricular wall thicker
left
how to ID pulmonary vessels on radiographs
located on either side of the bronchi
lateral: cranial pulmonary vessels
DV: caudal pulmonary vessels
pulmonary veins vs arteries on radiographs
lateral:
- veins = ventral
- arteries = dorsal
DV:
- veins = medial
- arteries = lateral
normal cardiac size in lateral
dogs: 2.5-3.5 intercostal spaces
cats: 2.5 intercostal spaces
normal cardiac size in DV
heart occupies <2/3 thoracic width
what causes normal variations in cardiac size
- cardiac cycle (systole vs diastole)
- respiratory cycle (inspiration makes heart appear smaller)
- hydration status (dehydration decreases size)
- body condition (obesity increases heart size)
how does left atrial enlargement appear on radiographs
- bulge in LA area
- flattening of caudal aspect in lateral
- elevated trachea
- “bowlegged cowboy”
ddx for enlarged LA on radiographs
- mitral insufficiency
- cardiomyopathies (DCM, HCM)
- L to R shunts (PDA, VSD)
is right or left atrial enlargement more common
left atrial enlargement
how does right atrial enlargement appear on radiographs
- bulge in RA area
- widened cardiac silhouette on lateral (enlarged in cranial caudal direction)
ddx for enlarged RA
- tricuspid insufficiency
- severe pulmonic stenosis
- cardiomyopathies
how does left ventricular enlargement appear on radiographs
- elongation of the heart
- elevated trachea
- prominent apex
- bulge in LV area
ddx for left ventricular enlargement
- sub aortic valve stenosis (dogs)
- cardiomyopathies (HCM; cats)
- mitral insufficiency
how does right ventricular enlargement appear on radiographs
- “reverse D” shape
- widened cardiac silhouette on lateral
- cranio-ventral bulge
- elevation of apex from the sternum
ddx for right ventricular enlargement
- pulmonic stenosis
- pulmonary hypertension
- tricuspid insufficiency
- cardiomyopathies
what is the main cause of generalized/multi chamber enlargement in dogs
dilated cardiomyopathy or pericardial effusion
DCM on radiographs
enlarged, normal shape and margins of auricles and apex
pericardial effusion on radiographs
enlarged and rounded w/ sharp margins
circular on DV
what is the main cause of generalized/multi chamber enlargement in cats
hypertrophic cardiomyopathy or dilated cardiomyopathy
HCM on radiographs
less marked enlargement than DCM
large base with narrow apex (valentine’s heart)
peritoneal pericardial diaphragmatic hernia (PPDH)
herniation of the small intestines through an opening from the diaphragm into the pericardium
caudal vena cava size on radiographs
<1.5x aorta
aorta does not change size easily –> use as a marker for CVC size
what does an enlarged CVC indicate
right heart failure OR volume overload
how to evaluate pulmonary vessel size
arteries: should be smaller than the 9th rib on DV
veins: should be same size as arteries
what does enlarged pulmonary vessels indicate
arteries: bulge of pulmonary trunk
veins: left sided congestive heart failure
enlarged cardiac arteries/veins
- fluid overload
- left to right shunts
causes of small cardiac arteries and veins
- dehydration/hypovolemia
- right to left shunts
- severe pulmonic stenosis
