Transcript Name of presentation

Thoracic Radiology
Wendy Blount, DVM
Nacogdoches TX
Thoracic Rads - Normal
Why is it so difficult to evaluate cardiac
and chamber size on radiographs?
• Comparing heart size to lung field size
doesn’t work
– Dogs of different conformation have different
ratios of heart size to lung size
– Lung field size changes with the breathing cycle
– Abdominal fat pushes the diaphragm cranially
– Thoracic fat makes lung fields appear smaller
• Comparing heart size to vertebral size
works better
– Vertebral heart score
Thoracic Rads - Normal
Why is it so difficult to evaluate cardiac
and chamber size on radiographs?
• Things can make the heart look bigger
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Pericardial fat
Pericardial effusion
Peritoneopericardial diaphragmatic hernia
Oblique positioning on VD/DV can make right
heart look bigger
• MYTH - “increased sternal contact”
means right heart enlargement
Thoracic Rads - Normal
Normal cats change with age
• Long axis of the heart is more
horizontal in old cats (40%)
• Aortic bulge (30%)
– Not due to hypertension or hyperthyroidism
– At the aortic isthmus
– Measurements in young & old cats are the same
Thoracic Rads - Normal
Vertebral Heart Score
• Measure heart long axis
5.0 + 4.8 = 9.8
– carina to the apex
• Measure heart short axis
– Widest perpendicular to length
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Count vertebrae from cranial aspect T4
Add together
Dogs – normal 8.5-10.5
Cats – normal 7-8
Thoracic Rads - Normal
Heart Chambers – VD/DV
• LV 3-6 o’clock
• Aorta 12-1 o’clock
• RV 5-9 o’clock
• MPA 1-2 o’clock
• LA has to be really big to see on VD
• RA 9-12 o’clock
Thoracic Rads - Normal
Review of thoracic radiographs
• Skeletal
– Spine, front limbs, ribs, sternum
• Cranial abdomen
• Airways, Lung fields
• Great vessels
– Aorta, pulmonary arteries, cranial & caudal vena cava
• Smaller vessels
– Internal thoracic arteries, pulmonary lobar a & v,
brachiocephalic trunk, left subclavian artery
• Cardiac silhouette
– Vertebral heart score, bulge
• Left Heart Failure? Right Heart Failure?
Thoracic Rads - Normal
Heart Chambers – Lateral
• LA – caudal waist – 12-3 o’clock
• LV 2-6 o’clock
• Aorta 10-11 o’clock
• Raur 9 o’clock (RA not on lateral)
• RV 6-9 o’clock
• MPA 11-12 o’clock normal
– Bulge often 1-2 o’clock
Thoracic Rads - Abnormal
6.2 + 5.9 = 12.1
Case #1 – 8 year old neutered male cocker
spaniel - coughing
• Skeletal
• Cranial abdomen
– No abnormalities noted
• Airways, Lung fields
– Mild perihilar edema
• Great vessels
– enlarged caudal vena cava
• Smaller vessels
– enlarged pulmonary lobar veins
• Cardiac silhouette
– Generalized cardiomegaly, enlarged LA
Thoracic Rads - Abnormal
Case #1 – 8 year old neutered male
cocker spaniel - coughing
• Left Heart Failure
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Mild perihilar edema
enlarged pulmonary lobar veins
enlarged LA (generalized cardiomegaly)
Enlarged LV (elevated trachea)
• Right Heart Failure
– enlarged caudal vena cava
– Generalized cardiomegaly (RV enlargement)
– (ascites, pleural effusion)
Thoracic Rads - Abnormal
Case #1 – 8 year old neutered male
cocker spaniel - coughing
• Diagnosis by echo - DCM
Thoracic Rads - Abnormal
Are rads or echo better for detecting
congestive heart failure?
• radiographs
Are rads or echo better for detecting
enlarged heart chambers?
• echo
Thoracic Rads - Abnormal
Generalized cardiomegaly
(all 4 heart chambers enlarged)
Dogs
• Dilated Cardiomyopathy
• Mitral regurgitation
• Tricuspid regurgitation
Cats
• Dilated cardiomyopathy
• anemia
Thoracic Rads - Abnormal
Pseudocardiomegaly
• No significantly enlarged heart chambers
• Significantly enlarged cardiac silhouette
• Pericardial effusion
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Hemorrhage – heart base tumor
Right heart failure – modified transudate
Infectious pericarditis
Idiopathic pericarditis
• Peritoneopericardial Diaphragmatic
Hernia
• Pericardial fat
Thoracic Rads - Abnormal
Case #2 – 15 month Maine coon cat
5.1 + 3.8 = 8.9
– tachypnea, lethargy
• Skeletal & cranial abdomen
• Airways, Lung fields
– No abnormalities noted
• Great vessels
– caudal vena cava somewhat enlarged
• Smaller vessels
– No abnormalities noted
• Cardiac silhouette
– Generalized cardiomegaly, apex shifted right
Thoracic Rads - Abnormal
Case #2 – 15 month Maine coon cat
– tachypnea, lethargy
• Heart Failure??
– Probably not
• Diagnosis
– Echo showed dilation of LV and RV
– Flea Anemia (PCV 10%)
Thoracic Rads - Abnormal
6.0 + 7.1 = 13.1
Case #3 – 5 year old Maltese
– honking cough
• Skeletal & cranial abdomen & small vessels
– No abnormalities noted
• Airways, Lung fields
– Elevated trachea, compression of left bronchus
– Focal pulmonary edema
• Great vessels
– Bulge at 1:30 on VD
• Cardiac silhouette
– Generalized cardiomegaly, apex shifted right, LA enl
Thoracic Rads - Abnormal
Case #3 – 5 year old Maltese
• holosystolic murmur loudest L apex
• continuous murmur is heard loudest at
the left axilla
• Left Heart Failure
– pulmonary edema, LA enl, tracheal elevation
• Airway Cough
– compression of left bronchus and trachea
• Bulge at 1:30 on VD, apex shifted right
– cardiomegaly (R or L or both?)
Thoracic Rads - Abnormal
Case #3 – 5 year old Maltese
• Diagnosis by echo - PDA
– Right heart normal
LISTEN TO THE LEFT ARMPIT!!
When the left heart is markedly enlarged,
right heart size can be difficult to
evaluate
Thoracic Rads - Abnormal
Case #4 – 12 year old Mini Poodle
- holosystolic murmur L apex
• Skeletal, cranial abdomen, airways,
Lung fields, Great vessels, small vessels
– No abnormalities noted
• Cardiac silhouette
– VHS high if you include LA
– VHS normal if you exclude LA
– Huge LA
• No signs of congestive heart failure
Thoracic Rads - Abnormal
Case #4 – 12 year old Mini Poodle
- holosystolic murmur L apex
• Diagnosis
– Mitral regurgitation
• Treatment
– None needed
• Monitoring
– Chest rads every 6 months
– Sooner if respiratory rate while sleeping >40
Thoracic Rads - Abnormal
Case #4 – 12 year old Mini Poodle
- holosystolic murmur L apex
You can have a Huge LA and even LV
without CHF
CHF is rarely present without enlarged LA
Thoracic Rads - Abnormal
Case #5 – 4 year old DSH
4 + 3.5 = 7.5
- Murmur heard on annual – left sternum
• Skeletal, cranial abdomen, Lung fields,
airways, Great vessels, small vessels
– No abnormalities noted
• Cardiac silhouette
– VHS normal
– Enlarged LA on VD
• No signs of congestive heart failure
Diagnosis by echo - HCM
Thoracic Rads - Abnormal
Case #5 – 4 year old DSH
- Murmur heard on annual – left sternum
LA is seen more easily on the VD in cats
• LA sits more cranial in the cat
LA is seen more easily on lateral in dogs
VHS usually does not include LA in cats
• Other chambers need to be enlarged to perceive
cardiomegaly on the lateral in cats
Thoracic Rads - Abnormal
Case #6 – 10 year old mixed dog
- Gagging up white foamy fluid, mitral
murmur
• Skeletal, Cranial abdomen, Great vessels
– No abnormalities
• Airways, Lung fields
– Elevated trachea, compressed left bronchus
– Perihilar edema
• Smaller vessels
– enlarged pulmonary lobar veins
• Cardiac silhouette
– VHS 11.5, generalized cardiomegaly, enlarged LA
Thoracic Rads - Abnormal
Case #6 – 10 year old mixed dog
- Gagging up white foamy fluid, mitral
murmur
• Left Heart Failure
• Echo diagnosis – severe mitral
regurgitation
Thoracic Rads - Abnormal
Case #7 – 1 yr old Golden Retriever
- Episodes of collapse with exercise
• Skeletal, Cranial abdomen, Airways,
Lung fields, small vessels
– No abnormalities
• Cardiac silhouette
– VHS 9.5, aortic bulge on lateral, enlarged LA
• No signs of congestive heart failure
• Echo diagnosis – severe SAS
Thoracic Rads - Abnormal
Case #7 – 12 yr old Mixed Terrier
- Chronic cough and cyanosis
• Skeletal, Cranial abdomen, Vessels
– No abnormalities
• Airways, Lung fields
– Pronounced airway pattern
• Cardiac silhouette
– VHS 10-10.5, RV enlargement, apex shifted L
• No heart failure
Thoracic Rads - Abnormal
Case #7 – 12 yr old Mixed Terrier
- Chronic cough and cyanosis
• Echo diagnosis
– RV thickening
– Pulmonary hypertension
• Clinical Diagnosis
– Severe chronic pulmonary disease
Thoracic Rads - Abnormal
Case #7 – 12 yr old Mixed Terrier
- Chronic cough and cyanosis
What does it mean when the apex is
shifted right?
– LV enlargement or generalized cardiomegaly
What does it mean when the apex is
shifted left?
– RV enlargement
Thoracic Rads - Abnormal
Case #7 – 12 yr old Mixed Terrier
- Chronic cough and cyanosis
RV enlargement must be moderate to
severe to see on rads
RA enlargement difficult to appreciate on
rads unless severe (cause)
– TR
Lifting of the apex off the sternum on
lateral view means RV enlargement
Thoracic Rads - Abnormal
3.75 / 1 = 3.75
Measuring RV enlargement on
Lateral View of the Thorax
1. Measure heart long axis
• Carina to apex
2. Measure heart short axis
• Widest point perpendicular to long axis
3. Short Axis - Divide Cranial part by
Caudal part
• Cranial is <2.5x Caudal in normal dogs
• (Cr >2.5x Cd) means RV enlargement
Thoracic Rads - Abnormal
Case #8 – 10 month old English Pointer
Ejection murmur loudest at left heart
base
• Skeletal, Cranial Abdomen, Airways,
Lung fields, small vessels
– normal
• Great vessels
– pulmonary artery enlarged
• No signs of Congestive Heart Failure
Thoracic Rads - Abnormal
Case #8 – 10 month old English Pointer
Ejection murmur loudest at left heart base
• Causes of enlarged MPA (dogs)
– PS
– PDA
– Pulmonary hypertension (lobar aa also enlarged)
• MPA enlargement
– Not easily seen on lateral in dogs
– not readily seen in cats
• This case – echo diagnosis
– PS
– RV thickening
Thoracic Rads - Abnormal
Case #9 – 6 month old poodle with
murmur found on physical exam
Causes of enlarged pulmonary lobar
arteries
-Caudal lobar aa should be same width as a rib
-cranial lobar aa 0.75x 3rd or 4th rib
• PDA
– Pulmonary lobar veins enlarged also
– Called “pulmonary overcirculation”
• Pulmonary hypertension
• Heartworm Disease
Thoracic Rads - Abnormal
Case #10 – 5 yr old DSH cat
tachypnea
Causes of enlarged Caudal vena cava
-size varies with respiratory cycle
-only severe enlargement is reliably detected
-maximum width < length T5 or T6
• Right heart failure
Thoracic Rads - Abnormal
Case #11 – 2 yr old DSH cat
tachypnea
• Left Heart Failure
• Right Heart failure
• Echo diagnosis – hypertrophic
cardiomyopathy
Thoracic Rads - Abnormal
Case #12 – 6 yr old Westie
ADR
• Clinical diagnosis – severe dehydration
• Causes of microcardia
– Severe dehydration
– Addison’s Disease
– Pneumothorax (heart lifted off the sternum)
Thoracic Rads - Review
Left Heart Failure
• Pulmonary edema
• Pleural effusion in cats
• Pulmonary lobar veins much larger than
arteries
• Enlarged LA
– Not a sign of heart failure per se
– But LHF is rarely present without LA enlargement
• + Enlarged LV
– Tracheal elevation
– Cardiomegaly (increased VHS)
Thoracic Rads - Review
Right Heart Failure
• Pleural effusion
– Can obscure evaluation of the heart, lungs and
great vessels
• Enlarged caudal vena cava
• Ascites
– Modified transudate
• Often concurrent with left heart failure
– Generalized cardiomegaly (increased VHS)
Thoracic Rads - Review
Chronic Bronchitis
• Increased or mineralized airway
pattern
• Peribronchiolar infiltrates
– May progress to bronchopneumonia
– Interstitial pattern
– Alveolar pattern (air bronchograms) if severe
• Signs of pulmonary hypertension
– Enlarged pulmonary artery and lobar aa
• No signs of heart failure
Thoracic Rads - Review
Patent Ductus Arteriosus
-left to right shunt (aorta to MPA)
-volume expansion
• + Enlarged pulmonary artery
• + Pulmonary overcirculation
– Enlarged pulmonary lobar aa & vv
• Enlarged descending aorta
• Enlarged LV
– Tracheal elevation
– Increased VHS
• Enlarged LA
– + compression left bronchus
• + pulmonary edema
Thoracic Rads - Review
Sub-Aortic Stenosis
-pressure overload left side
• + Enlarged LV
– Increased VHS
– Not as marked as volume overload
• Enlarged ascending aorta
• Left Heart Failure due to aortic
insufficiency is rare
Thoracic Rads - Review
Pulmonic Stenosis
-pressure overload right side
• + Enlarged RV
– Not as marked as volume overload
• Enlarged MPA
• Right Heart Failure due to pulmonic
insufficiency is rare
Thoracic Rads - Review
Ventricular Septal Defect
-left to right shunt (LV to RV)
-volume expansion
• + RV enlargement
• + Pulmonary overcirculation
– Enlarged pulmonary lobar aa & vv
• Enlarged LV
– Tracheal elevation
– Increased VHS
• Enlarged LA
– + compression left bronchus
• + pulmonary edema
Thoracic Rads - Review
Atrial Septal Defect
-left to right shunt (LA to RA)
-lower pressure differential, so no
significant volume expansion
• + RV enlargement
• + RA enlargement
– Enlarged pulmonary lobar aa & vv
• Heart failure is rare
(handout)