Thoracic Radiology

1
Thoracic Radiology

• Wendy Blount, DVM
• Nacogdoches TX

2
(No Transcript)
3
Thoracic Rads - Normal

• Why is it so difficult to evaluate cardiac and
  chamber size on radiographs?
• Comparing heart size to lung field size doesnt
  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

4
Thoracic Rads - Normal

• Why is it so difficult to evaluate cardiac and
  chamber size on radiographs?
• Things can make the heart look bigger
• 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

5
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

6
Thoracic Rads - Normal
5.0 4.8 9.8

• Vertebral Heart Score
• Measure heart long axis
• carina to the apex
• Measure heart short axis
• Widest perpendicular to length
• Count vertebrae from cranial aspect T4
• Add together
• Dogs normal 8.5-10.5
• Cats normal 7-8

7
Thoracic Rads - Normal

• Heart Chambers VD/DV
• LV 3-6 oclock
• Aorta 12-1 oclock
• RV 5-9 oclock
• MPA 1-2 oclock
• LA has to be really big to see on VD
• RA 9-12 oclock

8
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?

9
Thoracic Rads - Normal

• Heart Chambers Lateral
• LA caudal waist 12-3 oclock
• LV 2-6 oclock
• Aorta 10-11 oclock
• Raur 9 oclock (RA not on lateral)
• RV 6-9 oclock
• MPA 11-12 oclock normal
• Bulge often 1-2 oclock

10
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

11
Thoracic Rads - Abnormal

• Case 1 8 year old neutered male cocker spaniel
  - coughing
• Left Heart Failure
• 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)

12
Thoracic Rads - Abnormal

• Case 1 8 year old neutered male cocker spaniel
  - coughing
• Diagnosis by echo - DCM

13
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

14
Thoracic Rads - Abnormal

• Generalized cardiomegaly
• (all 4 heart chambers enlarged)
• Dogs
• Dilated Cardiomyopathy
• Mitral regurgitation
• Tricuspid regurgitation
• Cats
• Dilated cardiomyopathy
• anemia

15
Thoracic Rads - Abnormal

• Pseudocardiomegaly
• No significantly enlarged heart chambers
• Significantly enlarged cardiac silhouette
• Pericardial effusion
• Hemorrhage heart base tumor
• Right heart failure modified transudate
• Infectious pericarditis
• Idiopathic pericarditis
• Peritoneopericardial Diaphragmatic Hernia
• Pericardial fat

16
Thoracic Rads - Abnormal

• Case 2 15 month Maine coon cat
• 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

5.1 3.8 8.9
17
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)

18
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 130 on VD
• Cardiac silhouette
• Generalized cardiomegaly, apex shifted right, LA
  enl

19
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 130 on VD, apex shifted right
• cardiomegaly (R or L or both?)

20
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

21
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

22
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 gt40

23
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

24
Thoracic Rads - Abnormal

• Case 5 4 year old DSH
• - 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

4 3.5 7.5
25
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

26
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

27
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

28
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

29
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

30
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

31
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

32
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

33
Thoracic Rads - Abnormal
3.75 / 1 3.75

• Measuring RV enlargement on Lateral View of the
  Thorax
• Measure heart long axis
• Carina to apex
• Measure heart short axis
• Widest point perpendicular to long axis
• Short Axis - Divide Cranial part by Caudal part
• Cranial is lt2.5x Caudal in normal dogs
• (Cr gt2.5x Cd) means RV enlargement

34
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

35
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

36
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

37
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 lt length T5 or T6
• Right heart failure

38
Thoracic Rads - Abnormal

• Case 11 2 yr old DSH cat
• tachypnea
• Left Heart Failure
• Right Heart failure
• Echo diagnosis hypertrophic cardiomyopathy

39
Thoracic Rads - Abnormal

• Case 12 6 yr old Westie
• ADR
• Clinical diagnosis severe dehydration
• Causes of microcardia
• Severe dehydration
• Addisons Disease
• Pneumothorax (heart lifted off the sternum)

40
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)

41
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)

42
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

43
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

44
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

45
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

46
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

47
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)