Cardiovascular Radiology Flashcards
How do you tell thoracic rads are good positioning
Vertebrae
Spinous processes (tear drop shaped)
centered on heart
image take at inspiration
What are the radiographic limitations
-Insensitive to heart chamber changes
-Nonspecific for diagnosis
-Mild enlargement debatable
-Phase of cardiac cycle can effect
-Rotation and degree of inspiration affects interpretation
Echocardiogram is the method of choice for evaluating and assessing anatomy, pathology, and function - includes individual chambers and part of vascularization
What are the benefits of radiology over Echo
Provides evaluation of pulmonary circulation as an indicator of cardiac function
-evaluates pulmonary vessels
-Evaluates pulmonary parenchyma
-Treatment Response (ex: cats with HCM)
What are you evaluating with the heart
-Size
-Chambers/vessels
-Apex location
-vessels (pulmonary)
-Lung prenchyma/ pleural space
How large is the normal dog’s heart?
2.5-3.5 intercostal spaces wide on lateral
breed variation
VD/DV: Half to 2/3 width of thorax or less
extensive breed variation
How large is the normal cat’s heart
2-2.5 ICS on lateral on lateral
VD/DV: approx 50% width of thorax on VD
Normal Dog’s heart on lateral is
2.5-3.5 intercostal spaces wide
extensive breed variation
Normal dog’s heart on VD/DV is
1/2 - 2/3 width of thorax
extensive breed variation
How do you take a vertebral heart sum in dogs
Draw your lines in short and long axis
take each line and measure parallel to the thoracic spine beginning at T4 veterbral body
Count the number of number of veterbrae caudally
Sum the number of vertebrae caudally
dogs normal 8.5-10.5
What is a dog’s normal VHS
8.5-10.5 vertebral bodies
What is a normal cat VHS
7.5 +/- 0.3 vertebrae
How should the cardiac apex be normally positioned
VD: apex positioned slightly to the left on midline
Lateral: apex adjacent to caudal sternum with adjacent fat outlines
what is the normal trachea relationship
deviates ventrally from the spine along course to heart base
*pushed dorsally by heart enlargement
On VD/DV, what is located at 11-1
aortic arch- primarily closer to 1:00
what cardiac chamber is located at midline
left atrium
On lateral, what is located in the cranial dorsal cardiac silhouette
Right atrium
aorta
main pulmonary artery
*Must use VD/DV to to distinguish further
On lateral, what is located in the caudal dorsal cardiac silhouette?
Left Atrium
sometimes have tracheobronchial lymph nodes there (tell apart from trachea being displaced dorsally with LA enlargement)
What are the radiographic findings of generalized cardiomegaly in the dog
1) Greater than 2/3 width of thoracic cavity (VD/DV)
2) Greater than 2.5 (cat) or 3.5 (dog) intercostal space on lateral view
3) Round shape to the heart +/-
4) Increased VHS (>10.5 dog)
What are the radiographic signs of left atrial enlargement
1) Straightening or rounding of caudo-dorsal heart margin / caudal waist (backpack sign)
2) Splitting of the mainstem bronchi (may compress- bowlegged cowboy)
3) Round opacity superimposed over caudal aspect of heart on VD (double opacity- apex)
summation of enlarged LA w rest of heart
4) Lateral: Left auricular bulge at 2-3oclock
Left Auricular bulges can be seen with left atrial enlargement, where is this seen
about 2-3 oclock on VD/DV
On lateral: what do you see that is enlarged with left atrial enlargement
Straightening or rounding of caudo-dorsal heart margin / caudal waist (backpack sign)
Where is the double opacity of left atrial enlargement seen
caudal aspect of heart on VD
-summation of enlarged LA with the rest of the heart
You will see bulge or round at 3-6:00 with_______
Left ventricular enlargement
What makes the heart taller on lateral
left ventricular enlargement (dorsal displaced trachea)
What are the radiographic findings of left ventricular enlargement
1) Lateral: heart taller (dorsally displaces the trachea)
2) Bulge/Rounding at 3-6 oclock
What are the clinical signs of right atrial enlargement
1) Lateral: Bulge in cranial-dorsal heart margin at the cranial waste
2) VD: Bulge at 9:00-11:00
What might cause right atrial enlargement in an older dog
Hemangiosarcoma
Tricuspid disease
On VD, what does a 9:00-11:00 bulge mean
right atrial enlargement
On VD, what does a 6:00-9:00 bulge mean
right ventricular enlargement
On lateral, where will the bulge with right atrial enlargement be
cranio-dorsal heart margin at the cranial waste
What are the radiographic findings of right ventricular enlargement
Lateral: Bulge at cranial ventral heart regions
Increased sternal contact
Elevated apex off sternum
VD: 6:00-9:00
What are the radiographic signs of aortic arch enlargement
Lateral: bulge at the cranial dorsal heart
VD/DV: bulge at 11:00-1:00 (close to mediastinum, noticed best on right side)
On lateral: where is the bulge with aortic arch enlargement
cranial dorsal heart
What does a bulge at 11-1:00 on VD tell you
aortic arch enlargement
-close to mediastinum, noticed best on the right side
On lateral: where will you see the bulge with MPA enlargement
cranial dorsal
What will you see with 1:00-2:00 bulge on VD
Main Pulmonary Artery enlargement
On lateral view, cranial lobe vessels should be ________________________
no larger than proximal 4th rib
On VD/DV: caudal lobe vessels should be measured ___________________________
after the 1st branch - no larger than the 9th rib
Vessels seen end on will look like ___________
Airways seen end on will look like ___________
Vessels: nodule
Airways: lucent because they contain gas
What is the most common congenital heart disease in dogs
PDA
What is the most common congenital heart disease in cats
VSD
What is the most common congenital heart disease in horses
VSD
Characteristics of stenotic lesions
1) Increased resistance of L or R ventricular ejection
2) Increased ventricular pressure
3) Ventricular hypertrophy
4) Turbulent blood flow through stenotic area- high speed jet causes aneurysmal dilation of vessel downstream from narrowed area (may see bulge on radiograph)
pulmoanry stenosis is common in
brachycephalic breeds
What are the 2 valvular stenotic lesions
1) Subaortic Stenosis
2) Pulmonary Stenosis
What are the radiographic signs of subaortic stenosis
1) Bulge at 11:00-1:00 (Aorta) - from turbulent blood flow
2) Large L Atrium (if secondary mitral dynsfunction)
3) L auricle
*Normal pulmonary vessels until MV dysfunction then can develop pulmoanry venous hypertension
With Subaortic stenosis, the pulmonary vessels are normal until there is
MV dysnfunction
then they can develop pulmonary venous hypertension
What breeds is subaortic stenosis commonly seen in
large breed dogs
german shephards
german short haired pointers
rottweiler
golden retriever
samoyed
others
malformation of pulmonic valve, less commonly narrow outflow tract
pulmonic stenosis
What are the 3 radiographic findings of pulmonic stenosis
1) Large MPA (1:00-2:00 on VD)
2) Right Ventricular enlargement (hypertrophy)
-elevation of apex on laterals
-increased sternal contact
-bulge at 6:00-9:00
3) Right atrial enlargement (9:00-11:00)
T/F: with pulmonic stenosis, pulmonary vessels are usually normal
true- may be small due to decreased cardiac output
With pulmonic stenosis, there is increased resistance to ejection leading to
R ventricular hypertrophy
With pulmonic stenosis there is turbulent blood flow leading to
Dilation of main pulmonary artery
What breeds commonly get pulmonic stenosis
-Brachycephalics (Bulldogs, Bostons)
-Terriers (Jack russel)
-Samoyed
-Labrador Retrievers
What are valvular incompetence diseases
leaky or malformed AV valves (tricuspid and mitral) that leads to a volume overload due to leaky valve and increased blood in chambers
can develop early heart failure
What do you see with mitral valve dysplasia
Left atrial enlargement +/- LV
may get pulmonary venous stenosis
What breeds get mitral valve dysplasia
bull terriers
german shephards
great danes
What are the radiographic findings of tricupsid valve dysplasia
1) Right atrial enlargement (9-11) from pressure and volume overload
2) Pulmonary vessels usually normal but can be small with decreased CO
What breeds commonly get tricuspid valve dysplasia
labrador retreivers
german shepherds
With shunting lesions, what should you look for
overperfused lung
most shunts are left to right so the right heart gets too much blood
leads to congestion/enlargement of the arteries and veins
see peripheral vessels better than usual because they are large
can progress to heart failure
what breeds commonly get ventricular septal defects
english bulldog
springer spaniel
common in cats
communication between the R and L ventricles, typically in membranous septum
Ventricular septal defect
T/F: ventricular septal defects are easy to identify on radiographs
False- it is hard
Echocardiography is essential
Ductus arteriosus connects the
aorta with the pulmonary artery
-bypasses the pulmonary circulation in the fetus
typically closes short after birth
What occurs with the ductus arteriosus is patent
Increased L sided pressure so blood flows from aorta through PDA to MPA
PULMONARY OVERCIRCULAION
What are the radiographic signs of ventricular septal defect
1) Variable heart enlargement (may look generalized depending on the size of the shunt)
2) Pulmonary overcirculation (Dilated A and Vein)
Abnormal lungs- ventral- interstitial
3) Bulge MPA
What radiographic changes is seen with PDA
3 knuckle sign
1) Proximal Descending Aorta - enalrged from turbulent flow
2) MPA enlargement: Increased pressure and flow
3) Enlargement of LEft atrium and L auricle: increased blood flow
4) Enlarged left ventricle (initially dilation
5) Enlarged pulmonary artery and vein (increased flow and pressure)
What is the 3 knuckle sign seen with PDA
1) Proximal Descending Aorta ~1:00
2) MPA (1:00-2:00)
3) L auricle (3:00)
+
generalized cardiomegaly
usualyl see 1-2 bulges (less commonly 3)
also see pulmonary overcirculation
What murmur is seen with PDA
continuous murmur with washing machine murmur
With the left side of the heart failing to push adequate blood into systemic circulation there is
increase LV pressure transmitted to the LA and pulmonary veins
veins get distended due to hypertension
fluid leaks from capillaries into the lungs (interstitial space then alveoli)
What are the radiographic findings of left sided heart failure
1) Dilated pulmonary veins
2) Interstitial to Alveolar Pattern
-Caudodorsal common, more diffuse is possible, asymmetric
3) Eventually pulmonary arterial hypertension (not common on rads)
What lung pattern is seen with left sided heart failure
Interstitial to Alveolar Pattern
caudodorsal is common
What is your diagnosis if you see opaque lungs interstital to alveolar pattern that is worse caudodorsal and a heart murmur
left sided heart failure
where do you typically see the lung pattern of left sided heart failure
caudodorsal
systemic venous congestion due to abnormal right function
blood backs up to venous circulation (vena cava, liver, spleen)
eventually get peritoneal and pleural effusion
right sided congestive heart failure
What are the radiographic signs of right sided congestive heart failure
large liver + spleen
liver rounded
free fluid in abdomen
enlarged CVC
pleural effusion
What are the radiographic changes seen with mitral valve insufficiency
1) Left Atrial enlargement
2) Progresses to Left Ventricular Enlargement
3) Cough caused by
-compressed of left caudal lobar bronchus and left sided CHF
What causes the cough seen with mital valve insuffiency
1) Left sided CHF
2) Compression of left caudal lobar bronchus
How do dog with mitrial valve insufficiency typically present
middle age to older small breed dogs
respiratory difficulty, cough, murmur
What dog breeds typically get dilated cardiomyopathy
large and giant
Doberman, great danes
boxer
cocker spaniel
What are the radiographic signs of canine dilated cardiomyopathy
1) Generalized cardiomegaly
2) Left atrial dilation (volume overload or MV dysfunction)
3) Pulmonary vein dilation
4) Pulmonary artery dilation
5) CHF
L- interstitial and bronchial (more typical)
R- pleural and/or abdominal effusion, hepatomegaly
heartworm disease affects any age over
6 months
mature heartworms live in the
right outflow tract-> cause pulmonary arterial intimal thickening (inflammation and mechanical obstruction)
What are the radiographic signs of heartworm disease
1) Main pulmonary artery enlargement - also from worms creating turbulent flow (1:00-2:00)
2) Right Ventricular Enlargement (hypertrophy)
3) Pulmonary arteries enlarged and tortuous
4) Pulmonary interstitial or alveolar pattern
-focal or multifocal to generalized
-local thromboemboli from worm fragments + focal pneumonitis/allergic response (eosinophilic bronchopneumopathy)
5) Possible R CHF
Heartworm causes possible left or right side heart failure
R CHF
What are the radiographic signs of pulmonary hypertension
1) Right Heart Enlargement
2) Large main pulmonary artery
3) Large tortuous pulmary arteries- can get pulmonary infiltrates
What cat breeds commonly get HCM
Maine Coon
Ragdoll
British Shorthair
Sphynx
Chartreux
Persians
What are the clinical signs of HCM
Murmur
Gallop
Dyspnea
Saddle thrombus
What are the radiographic findings of HCm
1) Mild to Severe Left Atrial Enlargement
2) Generalized cardiomegaly- becomes bean shaped on lateral
3) Classic Valentine Shape on VD/DV (R+L atria look enlarged - but L atria is enlarged
4) Can develop L sided CHF
-Large Pulmonary veins
-Interstitial to Alveolar Pattern
-Pulmonary pattern more patchy
Later develop pleural effusion
Do an echo
What might cause pericardial effusion in dogs
Right atrial masses
Idiopathic pericarditis
What are the radiographic findings of pericardial effusion in dogs
1) Variable cardiomegaly
2) Classic globoid appearance (large round heart on both views)
3) Caudo-dorsal border shape and curved -> no LA bulge
4) May have concurrent pleural effusion
5) Abdominal manifestations of right heart failure
-Dilated CVC
-Hepato-splenomegaly
-Ascites
What may cause a rightward and dorsal displacement of the trachea, cranial to the bifurcation
often laterally on VD/DV
Heart Base Masses
How should you distinguish DCM from pleural effusion
ECHO
