Lecture 3 thorax Flashcards
Vetebral heart scale
Measure widest and longest part and count vertebral bodies
Normal Dog: 9.7 +/- 0.5
Normal Cat: 7.5 +/- 0.3
Grey hounds and boxers: large hearts 11.6 +/- 0.6
Two primary branches off aortic arch
- Left subclavian
- brachiocephalic trunk
Lazy heart / redundant aortic knob or angular aorta
- 2 features of geriatric feline thorax
- Don’t mistake for lung mass in L. Cranial lung lobe
Interpretation paradigm for cardiac silhouette
- Is there cardiac enlargement? L, R, or both sides
- Is there radiographic evidence of right (pleural effusion) or left sided (pulmonary edema) cardiac failure
- Are the peripheral pulmonary arteries or veins enlarged? PA enlarged? PV enlarged? Both?
- Are there any lumps or bumps in area of the great vessels on the VD/DV projection (must be straight for accurate interpretation)
- Other Roentgen abnormalities associated with the cardiac silhouette?
Left Heart Failure
Pulmonary Edema
Dogs
- Pulmonary venous enlargement >> unstructured interstitial to alveolar (hilar to caudodorsal distribution)
- Both caudal lung lobes or right caudal lung lobe (eccentric mitral valve regurgitant jet)
Cats
- Multifocal and asymmetric w/o a specific lung lobe distribution
- Unstructured interstitial >> alveolar (same dz but different pattern)
- Enlarged pulmonary arteries and veins
Veins
Central and ventral
Caudo dorsal distribution of inc opacity
Pulmonary edema
Pleural effusion look for
Retraction of lung lobes
Falciform ligament
Fat on the abdominal side of the diaphragm
Right Atrium and ventrical enlargement
- Can happen independently
- Best viewed on VD
Reverse D (bottom left)
Right ventricular enlargement
Right atrial enlargement typical
Tricuspid disease
Right ventrical enlargement typical of
Pulmonic stenosis
Left atrial enlargement
- Backpack signs (backpack on top of heart)
- Signs of compression of left caudal mainstream bronchus
- TRACHEAL ELEVATION
Left to right patent ductus arteriosus: Roentgen signs
- Left sided cardiomegaly with left atrial and ventricular enlargement
- Pulmonary overcirculation with enlargement of both pulmonary arteries and veins
- Enlargement of the descending thoracic aorta (= ductus diverticulum)
- Enlargement of the main pulmonary artery (+/-)
- Left heart failure = pulmonary edema
- Tree knuckle sign on VD = classic finding
- enlargement of the MPA descending thoracic aorta and left auricle
Sub aortic stenosis
- Often no sig changes
- Widening of cranial mediastinum on VD
- Elongation of the left ventricle and cardiac apex on VD image (left ventricular hypertrophy
- Can get concomittent left atrial enlargement seconadry to mitral valve insufficiency
- Left heart failure: Pulmonary Edema
- Arrythmias common
- Predisposed to bacterial endocarditis of aortic valve
Tracheal elevation
Left atrial enlargment
Pulmonic stenosis
- Right sided cardiomegaly with right ventricular enlargement
- Pulmonary circulation: normal to undercirculated with small pulmonary arteries and veins
- Enlargement of the main pulmonary artery (+/-)
- Righ heart failure = pleural effusion
- Can have normal thoracic rads if mild/moderate stenosis and valvular gradient is not considered significant
Peritoneal Pericardial diaphragmatic hernia
- Generalized cardiomegaly with unusual shape and contour
- Normal pulmonary circulation
- No enlargement of descending thoracic aorta or main pulmonary artery
- Do not present in heart failure
- Differential opacities in the cardiac silhouette (fat/gas due to intestinal contents)
- Lack of abdomial viscera in cranil abdomen
- Dorsal peritoneopericardial mesothelial remnant seen ventral to cauda vena cava in cats
Mitral valve degenerative disease
Backpack signs and in severe cases dorsal displacement of trachea
- L sided cardiomegaly w/ L atrial and ventricular enlargement
- enlarged main body of left atrium = bowlegged cowboy sign on VD - Left heart failure = pulmonary edema
- Enlargement of left auricle when left atrium is moderately enlarged
- MV and TV result in generalized cardiomegaly
- MPA can be enlarged in cases of chronic elevated pulmonary veins and arteries
Dilated cardiomyopathy
- Left sided cardiomegaly with left atrial and ventricular enlargement
- Left heart failure = pulmonary edema
- can also have pleural effusion. This will effect right ventricle - Enlargement of left auricle when left atrium is moderately enlarged
- MV and TV insufficiency can result from annular dilation
- In Dobermans, the pulmonary edema can be seen in the accesory lung lobe
- WIll wipe out the caudal venal cava
- unstructured interstitial pulmonary pattern to an alveolar pulmonary pattern
Heartworm Disease
- Peripheral pulmonary artery disease (where HWs live)
- Enlarged, tortuous, blunted pulmonary arteries; right caudal lung lobe effected first
- After pulmonary hypertension => main pulmonary artery and right ventricular enlargement
- Enlarged caudal vena cava
=>caval syndrome
- RIght heart failure-pleural effusion
Pericardial Effusions / Heartbase Tumors
- Generalized cardiomegaly with ‘globoid’ cardial silhouette on VD/DV
- Righ heart failure - pleural effusion and ascites when in cardiac tamponade
- Most common cause in dogs is secondary to neoplasia
- Right auricular hemangiosarcoma or heartbase chemodectoma are most common tumor types
- Pulmonary metastatic disease from these tumor types are possible
Cardiomyopathies in cats
Valentine shape heart on VD/DV
- Change in cardiac shape
- Particularly caudal border of cardiac silhouette with a ‘bulge’
- looks like a jalapena pepper vs normal almond - Vantine heart shape on VD/DV consistent with either left atrial or both right and left atrial enlargement
- Enlargement of the left ventricle
- Pulmonary edema and/or pleural effusion present
- Pulmonary edema pattern is multifocal unstructured interstitial to alveolar
Hypertrophic cardiomyopathy in cats
extra notes
- Hypertrophic and restrictive
- Alveolar pattern and unstructured pulmonary pattern
- Lots of edema
- Pulmonary edema in a random multi-focal distribution
- NOT CAUDODORSAL - heart size can be 3X intercoastal space
Microcardia
- Heart less than 2 intercostal spaces on both lateral and radographs
- Widest point of cardiac silhouette on VD less than 40% pleural to pleural diameter at T8
- Small pulmonary vasculature
- Small caudal vena cava
- Seondary to Addison’s dz or any cause of hypovolemia
Diseases causing microcardia
- Addisons
- Hit by car
- Internal bleeding
- Hemangiosarcoma of spleen
Decreased lung opacity
Hypovolemia

Canine L heart

Right heart


Right sided heart failure
Pleural effusion



Left to right patent ductus arteriosus
Left sided cardiomegaly with L atrial and ventricular enlargement
Pulmonary overcirculation
- enlargement of both pulmonary arteries and veins
Enlargement of descending thoracic aorta
- ductus diverticulum
Classic finding is 3 knuckle sign

Sub aortic stenosis
often no significa thoracic findings
widening of cranial mediastinum
elongation of the left ventricle and cardiac apex on the ventrodorsal image

Pulmonic stenosis
Right sided cardiomegaly with right ventricular enlargement

Peritoneal Pericardial Diaphragmatic hernia

Dilated cardiomyopathy
Left sided cardiomegaly with left atrial and ventricular enlargement
Left heart failure = pulmonary edema