Radiography of Heart SDL Flashcards
what are the standard radiographic projections for assessment of heart
right lateral recumbency
dorsoventral
ideally when are the views taken
during inspiration (but can be only achieved using positive pressure ventilation in anaesthesized patients
what are visible on the radiographs
- cardiac shadow/silhouette
- ascending aorta
- descending aorta
- caudal vena cava
- pulmonary vessels
what is not visible on radiograph
- cranial vena cava
- brachiocephalic trunk
- subclavian vessels
what is the clockwise analogy
12-3: left atrium
3-5: left ventricle
5-8: right ventricle
8-10: right atrium
10-12: great vessels
identify the structures
what is the clockface analogy on DV
11-1: aortic arch
1-2: pulmonary artery
2-3: left auricular appendage
3-5: left ventricle
5-9: right ventricle
9-11: right atrium
how can cardaic size be assessed on right lateral view
height <66-70% of thoracic cavity (green and black lines)
width: 2.5 IC spaces large breeds, 3.5 IC spaces small breeds (yellow curved lines and blue arrows)
however, care must be taken when determining this as sometimes it can be difficult to determine the width of an intercostal space particularly if the dog is slightly rotated and the ribs are not overlying each other.
how are the cranial and caudal margins measured of the heart
The cranial and caudal margins should be curved and sloping as demonstrated by the dotted yellow lines and the outline of the cardiac shadow narrows slightly towards the top which is sometimes referred to as the cardiac “waist”. This is shown by the white arrows.
where is there contact on the borders of the heart
There is also usually just a small amount of contact between the ventral surface of the cardiac shadow and the sternum.
what is the normal appearance and position of the trachea
normally should diverge slightly from the vertebral column in a ventral direction as it runs caudally towards the bifurcation
how is the size of pulmonary vessels assessed
in lateral views the cranial lobar vessels can be seen crossing the 4th rib and their width should be no greater than the width of the proximal third of the 4th rib
what do the borders of the cardiac shadow appear as
beating causes a bit of a movement blur
on DV views what is the size of the cardiac shadow
should be less than 3/4 of the width of the thorax (<66%)
how is the thickness of the caudal lobar vessels
The caudal lobar pulmonary vessels can be seen on dorsoventral views and compared to the width of the 9th rib where they cross and should be no greater than the width of it.
what is the vertebral heart score
hieght: measure the length of the heart from the base at a point just below the tracheal bifurcation (crania) to the apex (yellow line)
width: right angles to this first measurement at the level of the caudal vena cava (blue line)
these measurements compared to the vertebral column starting at the cranial aspect of the vertebral body of T4 and the number of vertebral bodies that correspond with the length of the measurment are counted
total the numbers to give a score
ex. length of yellow line = 5 vertebral body lengths + 4 blue line = 9.5
how do breed/type affect cardiac size
- narrow/deep chested breeds: greyhound have very upright on lateral views with little contact with the sternum
- round/barrel chested: appear rounded and have increased area of sternal contact (basset)
- orientation of cardiac shadow
- degree of sternal contact
- vertebral heart score
**all normal their VHS are going to vary considerably
breed or shape of dog being imaged has a significant impact on the score
what is the difference in the cardiac shadow in cats compared to dogs
more sloping
should be determined at right angles to its long axis before comparison to the intercostal spaces
what are the normal ranges of VHS in cats
7.5-8.5 for all cats
no breed variations
