Radiology Heart and vessels

Define cardiac silhouette

Delineates external margins of heart/pericardium

3 pitfalls of rads with cardiac stuff

- unable to define internal features of cardiac chambers

- unable to determine wall thickness or chamber size

- unable to delineate valvular morphology

What makes up the dorsal 1/3 and ventral 2/3 cranial border on lat view

Dorsal 1/3

- MPA

- right auricle

- ascending aorta

Ventral 2/3

- wall of right ventricle and outflow tract

What makes up the dorsal 1/3 and ventral 2/3 of the caudal border on a lateral view

Dorsal 1/3

- left atrium (obscured by overlying pulmonary vessels)

- sulcus at junction of left atrium and left ventricle

Ventral 2/3

- left ventricular free wall

Clock face of the heart

•11:00 – 1:00 Aortic arch (AA)

•1:00 – 2:00 Main pulmonary artery segment (MPA)

•2:30 – 3:00 Left auricle (LAu)

•3:00 – 5:00 Left ventricle (LV)

•5:00 – 9:00 Right ventricle (RV) - large

•9:00 – 11:00 Right atrium (RA)

Where does the left atrium sit on the clock face

Located between main stem bronchi which straddle it like a cowboy

where is the aorta and cd. Vena cava located on VD

Aorta - superimposed with spine and heart on VD

Cd. Vena cava - superimposed with accessory lung lobe in right cd. Thorax on VD

What two diseases can cause segmental enlargement of aorta

- Aortic arch (AA) —> Subarotic stenosis (SAS/AS)

- proximal descending aorta —> PDA (patent ductus arteriosus)

Both of theses are congenital

What 2 pathologies can make the cd. Vena cava small/large

- small = hypovolemia or shock

- big = R. CHF —> secondary hepatomegaly and abdominal effiusion

**remember Cd. Vena cava can vary with cardiac cycle and phases of respiration but that is normal **

Enlargement of MPA is associated with what 2 pathologies

-pulmonary hypertension

-dz of pulmonary outflow tract (pulmonic stenosis, heartworm)

**mild MPA enlargement can be normal in some dogs - eval in light of other findings**

Where is left caudal pulmonary artery and right caudal pulmonary artery located in respect to trachea

Left - dorsal to tracheal bifurcation

Right - ventral to tracheal bifurcation

What is the ordering of pulmonary arteries and veins in relation to bronchi

ABV

-veins are ventral and central

-arteries are dorsal and peripheral

What is the general rule on size of pulmonary vessels

-equal to diameter of 9th rib as they cross it

-make sure arteries and veins are about the same size

VD/DV how to tell the difference

VD - Mickey Mouse ears diaphragm

-cd. Dorsal lung lobes collapsed (hard to see pathology here)

DV - one diaphragm bump

-cd lobar vessels are more visible

Feline cardiac silhouette and sizing on VD and lateral views

-almond shape

Lat view

-2/3 thoracic height

-2-2.5 IC spaces wide

-trachea deviates from spine

VD

-apex slightly left of midline

-broad convexity in area of right atrium and left ventricle

-flat left auricle area

What are two features that you would see on rads with a geriatric cat

Lateral

-cardiac silhouette inclines cranially

-vertical orientation of aortic arch (bump)

VD

-“elonagated heart”

-vertical orientation of AA appears end on like a false nodule

3 features of Deep chested dog hearts on lateral rad

-heart perpendicular to spine, 2/3 DV diameter

-2.5 IC spaces

-trachea deviates from spine

3 features of deep chested dogs hearts VD

-apex slightly left of midline

-circular to ovoid heart

-cupula and heart separation

3 features of intermediate dog hearts lateral rad

-3 IC spaces wide

-heart angled cr.dorsal, 2/3 DV diameter

-trachea deviates from spine

3 features of intermediate dog hearts on VD rad

-more elongated

-apex MORE to left of midline

-less separation between heart and cupula

4 features of shallow chested dogs hearts on lateral rad

-round heart

-2/3 or greater DV diameter

-3-3.5 IC spaces

-less tracheal deviation

-greater sternal contact

3 features on shallow chested dog hearts VD

-heart round to elongated

-apex VERY left of midline

-heart and cupula practically touching

What are the 2 types of angiocardiography available

Non-selective and selective

Selective angio vs non-selective

Contrast injected in peripheral vein vs Cather in area of interest

Diagnostic angiocardiography largely replaced by

Echocardiography

Why else would we use angiocardiography in vet med

Interventional cardiac procedures

Echo is defined as

Ultrasound of heart

-gold standard in dx most cardiac disorders

What is the most consistent rad indicator of heart disease

Cardiomegaly

How do we measure heart size on rads

Vertebral heart score

-put the heart width and length along the vertebrae starting at T4 = cumulative sum of vertebra between length and with = vertebral heart score

Normal vertebral heart score in dogs and cats

Dog 8.5-10.6 (9.7)

Cat 7.5 ± 0.3

what two parts of the heart will enlarge together

Atrial and ventricular enlargement of affected side go together

3 features of LAE on lateral

-dorsal displacement of main stem bronchi by a hunchback bump

-increased cd.dorsal cardiac border

-loss of cd.cardiac waist - straightening of cd.cardiac margin

What part of the heart is enlarged

LAE

3 features of LAE on DV

-double opacity sign

-separation of main stem bronchi

-LA bulge at 2:30-3 o’clock

What part of the heart is enlarged

LAE

3 features LVE on lateral

-tall heart (>2/3 DV diameter)

-dorsal displacement of trachea (almost parallel to spine)

-straightening of cd. border of heart

What part of the heart is enlarged?

LVE (technically LAE too) - prof used the same photo for both but outlined different features

3 features of LVE VD

-elongation of cardiac silhouette

-deviation of apex to the left

-bulge at 3-5 o’clock

What part of the heart is enlarged?

LVE

2 features of RAE on lateral

-dorsal bowing of trachea over cranial heart base @ bifurcation

-loss of cr.cardiac waist (R.atrium and MPA are here)

What part of the heart is enlarged?

RAE

RAE feature on VD

Bulge at 9-11 o’clock region ± RVE bulge

What part of the heart is enlarged?

RAE

2 features of RVE on lateral

-wide cardiac silhouette

-cr.margin super bowed out —> increased sternal contact

What part of heart is enlarged?

RVE

2 features of RVE on VD

-bulge 5-9 o’clock

-reverse D

What part of the heart is enlarged

RVE

Features of generalized cardiomegaly in dogs and what disease is associated with this?

-combo roentgen signs involving L and R cardiac chambers

-dogs often get mitral dz which results in both L+R heart enlargement

-tall + wide, sternal contact

what part of the heart is enlarged in this dog

Generalized (whole thing)

Generalized cardiomegaly in cats features and what disease associated with this

-change in shape = abnormal (hard to tell what chamber affected tho) —> results in valentine shape

-HCM —> big LA and L. Au —> probably baggy left atrium that makes the whole thing look “huge”

What part of the heart is enlarged in this cat

Generalized (the whole thing)

Microcardia cause

Dehydration, shock, Addisons (electrolyte imbalance)

Microcardia roentgen signs

-small cardiac silhouette (<2 IC in dog, <1.5 IC in cat)

-pulmonary hypoperfusion (small vessels)

-consistently small CdVC

-lung margins visible

-heart elevated off sternum

-still can trace vessels

What is going on with this dog heart?

Microcardia

What is going on with this cat heart?

Microcardia

How is heart failure defined radiographically

Rad evidence of inability of heart to adequately handle volume of returning blood

T/F cardiomegaly alone is considered an indicator of heart failure

FALSE, just b/c the heart is big does not mean it can’t handle that blood volume

LHF cannot handle the blood returning from what segment

Pulmonary circulation (lungs)

Roentgen signs of LHF Regarding the vasculature

-pulmonary vessel enlargement/congestion

-pulmonary veins > pulmonary arteries

-both arteries and veins are increased in size (esp cats)

Roentgen signs regarding pulmonary edema with LHF

-unstructured interstitial or alveolar infiltrates (perihilar cd.dorsal lung fields)

-multifocal patchy distribution (cats, dobby pinscher, acute tendinae rupture)

-peribronchial cuffing in cats may also cause bronchial pattern

-pleural effusion -cats

Multifocal patchy lung patterns are often seen in what 3 situations

-cats

-Doberman pinschers

-dogs with acute rupture of chordinae tendinae

What 4 patterns can cats have when LHF and where is it distributed

-unstructured interstitial

-alveolar

-bronchial

-pleural effusion

-distributed everywhere and anywhere

What are the 2 features of pleural effusion that help you differentiate it from other patterns?

-fissures lines with lungs

-no vessels can be traced

Cat - what sided HF is this

Dog - what sided heart failure is this

LHF

Cat- what sided heart failure

LHF

What features of this image screams this cat is in LHF

Pleural effusion

-scalloping and fissure lines present

-vessels are not traceable in cr.ventral thorax

Cat- what kind of heart failure is happening

LHF

RHF cannot handle the blood volume coming from what part of circulation

Systemic circulation

3 Roentgen signs of RHF

-enlarged cd.VC(Venous congestion)

-hepatomegaly (visceral congestion)

-ascites

at what point is this dog in heart failure

April - pulmonary vein enlargement and beginning of lung patterns forming

July - alveolar lung patterns, big pulmonary veins

3 congenital heart diseases

-pulmonic stenosis

-Subaortic/aortic stenosis

-PDA

what part of the outflow tract is obstructed in pulmonic stenosis

Right ventricular outflow tract

Pulmonic stenosis happens at what level

-subvalvular or valvular

Valvular is most common

What two breeds inherit pulmonic stenosis

Beagles, keeshonds

Other breeds at risk: English bulldog, mastiff, Samoyed, mini schnauzer, American cocker spaniel, WHWT

Roentgen signs of pulmonic stenosis

-Right heart enlargement (RVE +/- RAE) d/t PRESSURE OVERLOAD

-MPA enlargement

-Normal to small pulmonary vessels (hypoperfusion)

+/- RHF

pathogenesis of pulmonic stenosis

1.Narrow pulmonic valve

2.RV hypertrophies to try and muscle the blood through narrow valve

3.dilation of MPA after the stenotic region

What does the angiocardiography highlight in pulmonic stenosis

-RV hypertrophy

-narrowing pulmonary outflow tract

-post-stenotic dilation of MPA segment

What disease does this dog have

Pulmonic stenosis

What part of the outflow tract is obstructed in aortic stenosis

Left ventricular outflow tract

Aortic stenosis happens at what level

-subvalvular/valvular

Subvalvular (subaortic stenosis)

What breed is aortic stenosis heritable in

Newfoundland dogs

Other breeds: Rottweilers, boxers, golden, GSD (large breeds)

Roentgen signs of aortic stenosis

-survey rads could be NORMAL

-LH enlargement (LVE ± LAE) from PRESSURE OVERLOAD

-elongated cardiac silhouette

-AA bump

-low incidence of LHF

What ends up killing the dogs with aortic stenosis

Sudden death due to ventricular arrhythmias and impaired coronary arteries

Pathogenesis of aortic stenosis

1.subaortic abnormality

2.left ventricular hypertrophy

3.focal dilation of AA

What does the angiocardiography highlight in aortic stenosis

-AA bulge

-increased cardiac waist

-left ventricular hypertrophy

-narrowing of aortic outflow tract

-post stenotic dilation of AA

± mitral regurg

What disease does this dog have

Aortic stenosis

What fails to happen at birth in PDA dogs

Failure of ductus arteriosus to close after birth —> persistent shunt between aorta and MPA

Which direction is the PDA shunt

Left to right (can flip later in disease but don’t worry about that)

Roentgen signs of PDA

-BIG LVE, VOLUME OVERLOAD

-triple bump sign on VD (Prox desc. Aorta, MPA, L.Au)

-normal to large pulmonary vessels (hyperperfusion)

±LHF

Pathogenesis of PDA

1.shunt connection between aorta and pul artery

2.high pressure blood from aorta to pul artery —> dilate pul artery

3.hyperperfused lungs

4.dumps blood into left heart

5.big LA and LV

What does the angiocardiography highlight in PDA

-see the shunt

-left ventricular dilation

-opacification of aortic and pulmonary arteries

What disease does this dog have

PDA

5 acquired heart diseases

-heartworm

-canine CM

-feline CM

-endocardiosis

-cardiac neoplasia

Roentgen signs of heartworm disease

-RVE, RAE

-big MPA

-big pruned, tortuous pulmonary arteries (big sign in cats)

-pulmonary infiltrates with eosinophilia aka eosinophilia bronchopneumopathy

-mixed pulmonary patterns (unstructured interstitial bronchial, ± alveolar

-evidence of pulmonary thromboembolism (worm in outflow tract)

± RHF

What disease does this dog have

heartworm disease

What disease does this cat have

Heartworm disease

What type of CM do dogs most commonly get

DCM - ventricular volume overload —> eccentric hypertrophy

What breeds predisposed to DCM

Doberman, boxer, Great Dane, Labrador retriever (large breed dogs)

Roentgen signs of DCM

-Generalized cardiomegaly

± LHF > RHF or biventricular heart failure

-unstructured interstitial to alveolar in cd.dorsal