Cardiac Radiography Flashcards
What are the indiciation for thoracic radiography? (3)
–Identification, location and quantification of lesions producing respiratory signs (coughing) (typically dyspnoea/cough)
–Identification of lesions too small to produce clinical signs
•E.g. Looking for metastasis
–Assess effectiveness once we have started a treatment
What does radiography NOT identify?
CAUSE of heart disease
What type of heart failure is radiography good for? How do you know it is this?
Left heart failure
Evidence of cardiac enlargement?
Identify fluid in the lungs or pleural space
Why might it be hard to generate radiographs of diagnostic quality? (5)
–Movement blur (respiratory)
–Wide radiographic contrast
–Interpretation! (New grads- malcolm doesn’t agree..)
–Breed normals/age normals
–Inspiratory/expiratory
How can we minimise movement blur? (3)
- Careful handling
- Sedation/GA
–Dyspnoeic cat may just sit there
•Reduce exposure time
Wha positions may we do for radiography? What are they good to show?
•Lateral - right (left) - heart
–BOTH LATERALS – LUNG METASTASES
–Whetehr left or right laterally will depend on the x ray machine
- Dorsoventral - heart
- Ventrodorsal - lungs
- Only time we put it on the back is a chronic cough and signs are stable! Never put a resp difficulty case on their back
Why do we no longer use the following positions?
- Standing lateral
- Standing erect
- Recumbent VD with horizontal beam
Danger of the xray beam
What can obscure the thorax in lateral view?
Triceps
Where do we centre and collimate for lateral x ray?
Centre – cd scapula
Include small amount cr abdo
Thoracic inlet cr
What is the risk during interpretation if there is rotation?
Do not want to over-interpret
Where do we centre for a DV?
Caudal border of scapula
When would you do a VD view?
ONLY – chronic cough as you can get a good inspiratory bag by using breathing bag
As you want to see any evidence of airway making
What should we assess in the technical quality of a radiograph? (7)
- Pink camels collect extra large apples on inspiration!
- Positioning
- Centring
- Collimation
- Exposure
- Labelling
- Artefacts
- Inspiratory or expiratory? (hard to get fully inspiratory unless Ga and would need to interpret the film. No inspiratory – look more white (radiopaque)
What are some common artefacts to watch out for? (5)
- Skin folds
- Nipples
- Cartilage mineralisation
- Size and shape of cardiac silhouette
- “Collapse” of dependent lung - do DV first!
Which X ray do we do first? Why?
Do DV first!
Lateral first means the one lung collapses slightly
This I the same dog – l (lateral first an lung collapsed) and right is lateral second.
If you take lateral first give a couple of breaths first
What does it mean to Assess “not the heart and lungs”.?
Peripheral soft tissue structures.
Anterior abdominal contents.
Thoracic skeleton.
Cranial mediastinum.
Caudal mediastinum.
Diaphragm.
Pleural space.
Then lungs – cardiac silhouette and then vessels
What is the normal cardiac silhouette? Both for lateral and DV?
Rules of thumb for lateral (3.5 rib spaces max)
Rules of thumb for DV (2/3 of width of thorax at rib 6 max)
How can you assess heart size?
Draw a line from trachea bifurcation to heart apex
Normally – 4 chambers should be distributed
DV – draw the line apex to base
If you have a 8 yo grade 4 systolic murmur no other signs CKCS
What do you look for?
Let side enlaargment
What is the normal height of the heart in lateral?
5th rib - 2/3 heart of thorax
What is the difference in deep vs narrow chest breeds with the heart silohouette?
Deep chest Narrow more upright chest
Narrow chest – chunkier, rounded cardiac silhouette
On a DV image - where is the aniaml LHS on the image?
RHS
If you have a Bulge 1-2 Enlarged RHS. Loud systolic murmur at heart base. What would you suspect?
Pulmonary stenosis?
Looking at a DV heart what is at the ollowing times on a clock face:
- 12-1?
- 1-2?
- 2-4?
- 3-5?
- 5-9?
- 8-11?
- Aorta
- PA
- LA
- LV
- RV
- RA
What is the vertebral heart scoring system and how does it work?
Length (L) is measured on lateral vs no number of vb bodies.
(starting at the cranial edge of T4).
Width (W) measured similarly.
VERTEBRAL HEART SCORE (VHS) = L + W
Average in dogs is 9.7 (range 8.5 - 10.5), 8 in cats.
What should we find out from the cardiac silhouette? (3)
GENERALISED ENLARGEMENT.
INDIVIDUAL CHAMBER ENLARGEMENT.
- LEFT ATRIUM.
- RIGHT ATRIUM.
- LEFT VENTRICLE.
- RIGHT VENTRICLE.
CHANGES IN GREAT VESSELS.
How do you know if there is a problem with the heart of a PC with fluid?
Auscultate
What would this animal present with?
Heart this big must have evidence of heart disease - murmur, gallop etc.
What is seen with a pericardial effusion? What can we do to confirm?
- Whole cardiac silhouette grossly enlarged
- Globular appearance
- Outline distinct as no movement
- Secondary signs of right-sided failure
- Ultrasound very sensitive indicator –stick a probe on
What can be seen?
Generalised enlargement – cardiac
LA enlargement on lateral and splitting on mainstem bronchi
Should hear on auscultation
What is the problem with getting good at treating heart disease?
Heart can get super big - space occupying lesion
This is a small breed dog which has had treatment - what are the problems?
Huge cardiac silo. Trachea being pushed.
What is the issue here and what may hhave caused this?
Microcardia
Hypovolaemic animal
Small CS – here 2 rib spaces
What is seen with left heart enlargement?
LA – back and middle
Straightening of caudal border
Tenting of LA
What is shown here?
L
Heart Enlargement – Lat
Lost cd waist
LA is tenting
CS – tall
Arrow head (left) – large PV not surprised as large LA ad high pressure and the pressure in veins is high
Pulmonary venous HT
Hasn’t got any lung pattern – dog on the verge of pulmonary oedema (or been treated for) due to high venous pressure
V bigger than A above bronchus
What is seen on this image?
Left Heart Failure – Lat
Should know from CS coughing etc – pulmonary oedema
Alveolar pattern (typical of LHF in diaphragmatic lobes (not normally in cr lobe))
Generalised increased density
Air bronchograms
What is the issue here?
L Heart Enlargement – DV
See LA sitting on the back
Where is the right side of the heart on lateral and what happens if tehre s enlargement?
Right Heart Enlargement – Lat
Right wraps around left. Increase in sternal contact and crcd dimension of the hear
What is this?
Right Heart Enlargement - Lat
How can you tell on DV if there is R side enlargement?
Development of a reverse D
Where are the veins and arteries on DV? Where is easiest to see?
Veins – central
Arteries – lateral
Easier to see over diaphragm
What is seen here?
Right Heart Enlargement – DV
What is the normal feline heart shape and width on lateral?
–Width of heart is two IC spaces
–Looks like a lemon
What is the normal DV feline heart width?
–Width is 0.66 width of thorax at 5th rib
What happens in cat myocardial disease and what is the effect on the heart shape?
diastolic and heart cant fill = atria gets big. Wont be oval
Ventricle often normal
What does this show?
valentine heart and atria got big and ventricle normal
RCM/HCM – big atria
What is the normal cat size for:
Width DV?
Lateral short axis?
Lateral long axis?
What changes in thoracic radiographs of older cats (3)
More horizontal heart
Prominent aortic arch (lays down on sternum a bit more )
Often have “spare” trachea and looks wavy
What is the problem here?
Heart enlargement
By the time we see cats with HF – profound changes
Wide CS and pushing trachea up
Huge atria
What is radiography not useful for in myocardial dx?
Distinguishing the forms of disease?
