Diagnostic Imaging of Heart Flashcards
what info does radiography provide about heart (4)
- overall size
- shape (chamber enlargement)
- location
- evidence of congestive failure (pulmonary edema)
what does radiography of the heart not show (3)
- internal structures of the heart (valve, leaflets, ventricular septum)
- myocardial function
- valve incompetence
what info does ultrasound of the heart provide
- chamber size
- myocardial function
- blood flow and leakage through valves
- disease of internal cardiac structures
what does ultrasound not provide
less useful for evidence of congestive failure
what does full assessment of the heart require
both radiography and echocardiography
identify the structures of the thorax
heart
red: aorta (dorsal caudal)
white: trachea (ending over the heart base where it divides, gas filled)
yellow: bronchi (large)
blue: pulmonary vessels (large)
orange: caudal vena cava
can’t really see mediastinum or esophagus (unless dilated)
what are the strucutres of
heart
red: aorta (superimposed from spine)
white: trachea (swings slightly to right of midline in cranial thorax but most is underneath spine)
yellow: bronchi (large)
blue: pulmonary vessels (large)
orange: caudal vena cava (going across from diaphragm to the heart on right side of midline)
what is roentgen signs of the heart radiograph
- size
- shape
- opacity
- margins
- location
- number
what radiograph views are the heart best asses on
right lateral recumbency
dorsoventral radiographs
what is the number of intercostal spaces the heart size is in the dog and cat
dog: 3-3.5
cat: 2-3
what is the height of the thorax in the dog and cat
~2/3 in both dog and cat
what is the width of the thorax in the dog and cat
dog: 1/2-2/3
cat: 1/2-2/3
what is the position of the heart in the dog and cat (3)
- middle mediastinum
- 4-6th intercostal space
- degree of sternal contact partially depends on breed
(shadow not picture)
is this dog or cat thorax
dog
is this the dog or cat
cat
what is this radiograph showing (height of thorax, intercostal spaces)
yellow: >2/3 height of thorax (with elavation of trachea –> trachea is running parallel to thoracic vertebrae)
red: > 3.5 intercostal spaces covered
heart is too large
what is the clock position of the left atrium in RLR
12-3
what is the clock position of the left ventricle in RLR
3-5
what is the clock position of the right ventricle in RLR
5-8
what is the clock position of the right atrium in RLR
8-10
what is the clock position of the great vessels in RLR
10-12
summarize the heart shape in RLR in the clock analogy
12-3: LA
3-5: LV
5-8: RV
8-10: RA
10-12: great vessels
what is the heart shape in clock analogy
11-1: aortic arch
1-2: pulmonary artery
2-3: left auricular apeendage
3-5: left ventricule
5-9: right ventricle
9-11: right atrium
(5-7 on top of right ventricle = left atrium)
how do you calculate the vertebral heart score
X + Y = VHS
base of heart to the apex of the heart and then the widest part –> count the number of verticle bodies each line covers and add them up
what is the approx vertebral heart score in dogs and cats
dogs: ~8.7-10.7
cats: ~7.5-8.5
what does vertebral heart score not take into account
breed variations
don’t use sole assessment of size
what are the different echocardiograph modes
- B mode: shows slice of anatomy
- M-mode: functional measurements
- doppler: quantitative and qualitative assessment of blood flow
what does M-mode of ultrasound show
movement or contraction of structures over time
allows measurement of myocardial contractility –> assessment of myocardial function
*shows how much ventricle wall is contracting and thinning during diastole and systole –> can calculate the % of the muscle is thickening and gives indication of myocardial function
what is doppler imaging
reflection of sound from moving object = change in frequency
allows measurement of blood flow
what are the colour of doppler imaging
BART
blue away and red towards
whats the difference between pulse and continuous doppler imaging
pulse: very percise under 1m/sec
continuous: less percise but can measure faster velocities
how is the heart scanned
lateral recumbency –> right and left
the lung will sink to lower thoracic wall (ultrasound doesn’t do well with gas)
scan from underneath (heart nearer dependent wall of thorax –> less interposed pulmonary tissue, hole in ultrasound table, scan right side of chest with patient in right lateral recumbency)
- small transducer (must fit between ribs)
- connect to ECG
avoid sedation if possible (affects myocardial contraction)
what is the right parasternal approach
most widely used scanning –> place transducer on apex beat of heart on right thoracic wall
what info does right parasternal approach provide
- chamber sizes
- myocardial function
- valve function
what are the scan planes of right parasternal approach
- cross sections/short axis
- long sections/long axis
what is the limitations of right parasternal approach
difficult to image all chambers together
what are the short axis views of right parasternal approach
what view is this
right parasternal short axis view of left ventricle
looks like mushroom
what view is this
right parasternal short axis view
mitral valve –> fishmouth view
right ventricle on top
what view is this
right parasternal short axis –> pulmonary artery with the pulmonary valve
tricky view to get –> interference with lungs
what are right parasternal long axis views
what view is this
right parasternal long axis view of left atrium and mitral valve
what view is this
right parasternal long axis of aorta
what is the left apical views and what is it useful for
pateint in left lateral recumbency
scan from dependent left thoracic wall
good “end on” views through: mitral and tricuspid valves (four chamber), aortic outflow (five chamber)
good for accurate measurements of blood flow velocities
what view is this
can see tricuspid and mitral valves
what are myocardial diseases
- dilated cardiomyopathy: reduced myocardial contractility, decreased cardiac output and dilation of chambers (common in large breed dogs)
- hypertrophic cardiomyopathy: decreased capacity of ventricles, reduced cardiac output (common in cats)
what are valvular diseases
- dysplasia (abnormal development)
- infection (endocarditis)
- leakage of valves and chamber dilation
what are pericardial disease
- fluid in pericardial sac –> prevents proper filling of heart chamber (esp. right ventricle) and reduces cardiac output
what is shown here
dilated cardiomyopathy (DCM)
large heart, DV would show much more than 2/3 of thorax
the heart should curve in towards the tracheal bifurcation
bulge in this area (12-3) –> left atria
what is shown here
dilated cardiomyopathy - M mode
not much contraction
what is shown here
dilated cardiomyopathy - B mode
should look like mushroom –> barely see the papillary muscles –> dilated
what is shown here
hypertrophic cardiomyopathy (HCM) –> valentine’s heart
trachea is still deviating heart doesn’t look tall –> maybe less ovoid shape
wall is thickening, narrowing inside of heart –> overall size of heart doesn’t increase but you get shape change better seen on DV
enlargement of atria
what is shown here
left ventricle should be mushroom shape
ventricular walls are very thick –> narrowing of lumen –> reduced stroke volume –> heart failure
what is shown here
mitral valve disease (endocardiosis)
cardiomegaly with left atrial enlargement
significant bulging in region of left atria
common in CKS
what is shown here
mitral valve disease
ventricle and atrium are same size
blood leaking from mitral valve back into ventricle
what is shown here
pericardial effusion
sharply marginated (sharp edges)
static cardiac silhouette
no significant left atrial enlargement
globoid shape
tracheal elavation
what is occuring here
pericardial effusion
sac of fluid
