Wendy Blount, DVM Nacogdoches TX Thoracic Radiology Wendy Blount, DVM Nacogdoches TX

Thoracic Rads - Normal Review of thoracic radiographs – 7 Steps 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, bulges Left Heart Failure? Right Heart Failure?

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

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

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

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

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

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

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

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

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

Thoracic Rads - Normal

Thoracic Rads - Normal

Thoracic Rads - Normal Normal cats change with age Long axis of the heart is more horizontal in old cats (40%) Aortic bulge develops (30%) Not due to hypertension or hyperthyroidism At the aortic isthmus Cardiac measurements in young & old cats are the same, despite these conformational changes in the thorax

Thoracic Rads - Normal 5.0 + 4.8 = 9.8 Vertebral Heart Score

Thoracic Rads - Normal Vertebral Heart Score Measure heart long axis carina to the apex Measure heart short axis Widest point perpendicular to length 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 - Left LV - Left Ventricle AV - Aortic Valve (AoV) AA - Ascending Aorta DA - Descending Aorta

Thoracic Rads - Normal Heart Chambers – VD/DV - Left LV - Left Ventricle AV - Aortic Valve (AoV) AA - Ascending Aorta DA - Descending Aorta LA – Left Atrium

Thoracic Rads - Normal Heart Chambers – VD/DV - Left

Thoracic Rads - Normal Heart Chambers – VD/DV - Right PV RV - Right Ventricle PV - Pulmonic Valve MPA - Main Pulmonary Artery RPA - Right Pulmonary Artery LPA - Left Pulmonary Artery

Thoracic Rads - Normal Heart Chambers – VD/DV - Right

Thoracic Rads - Normal Heart Chambers – VD/DV – Clock Face Aorta 12-1 o’clock LV 3-6 o’clock

Thoracic Rads - Normal Heart Chambers – VD/DV – Clock Face Aorta 12-1 o’clock MPA 1-2 o’clock LV 3-6 o’clock RV 7-9 o’clock

Thoracic Rads - Normal Heart Chambers – VD/DV – Clock Face Aorta 12-1 o’clock MPA 1-2 o’clock LV 3-6 o’clock RV 7-9 o’clock LA has to be really big to see on K9 VD

Thoracic Rads - Normal Heart Chambers – VD/DV – Clock Face Aorta 12-1 o’clock MPA 1-2 o’clock LV 3-6 o’clock RV 7-9 o’clock LA has to be really big to see on K9 VD RA 9-12 o’clock

Thoracic Rads - Normal Heart Chambers – Lateral – Left LA – Left Atrium MV – Mitral Valve LV – Left Ventricle AV – Aortic Valve (AoV) SV – Sinus of Valsalva AAo – Ascending Aorta BCT – Brachiocephalic Trunk LS – Left Subclavian a.

Thoracic Rads - Normal Heart Chambers – Lateral – Right RA – Right Atrium RAu – R Auricle RV – Right Ventricle MPA – Pulmonary a.

Thoracic Rads - Normal Heart Chambers – Lateral – Right RA – Right Atrium RAu – R Auricle RV – Right Ventricle MPA – Pulmonary a. RVOT – RV Outflow PV – Pulmonic Valve RPA – R Pulmonary a. LPA – L Pulmonary a.

Thoracic Rads - Normal Heart Chambers – Lateral – Clock Face LA (caudal waist) – 12-3 o’clock LV - 2-6 o’clock

Thoracic Rads - Normal Heart Chambers – Lateral – Clock Face LA (caudal waist) – 12-3 o’clock LV - 2-6 o’clock RV - 6-9 o’clock MPA – 10-11 o’clock – bulge at 1-2 o’clock

Thoracic Rads - Normal Heart Chambers – Lateral – Clock Face LA (caudal waist) – 12-3 o’clock CdVC – 2 o’clock LV - 2-6 o’clock RV - 6-9 o’clock RAu – 9 o‘clock RA not easily seen on the lateral view CrVC – 10 o’clock MPA – 10-11 o’clock – bulge at 1-2 o’clock

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel – coughing

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel – coughing

Thoracic Rads - Abnormal 5.8 + 5.8 = 11.6 Case #1 – 8 year old neutered male cocker spaniel – coughing

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel - coughing 1-2 - Skeletal, Cranial abdomen Mineralized costal arch 3 - Airways, Lung fields Mild tracheal elevation, Mild perihilar edema 4 - Great vessels enlarged caudal vena cava 5 - Smaller vessels enlarged cranial pulmonary lobar veins 6 - Cardiac silhouette Generalized cardiomegaly, enlarged LA 7 – RHF? LHF?

Thoracic Rads - Abnormal 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 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 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

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel – coughing

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel – coughing

Thoracic Rads - Abnormal Case #1 – 8 year old neutered male cocker spaniel - coughing Left Congestive Heart Failure Mild perihilar edema enlarged pulmonary lobar veins enlarged LA (generalized cardiomegaly) Enlarged LV (elevated trachea) Right Congestive 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 – advanced Tricuspid regurgitation - advanced Cats Dilated cardiomyopathy anemia

Thoracic Rads - Abnormal

Thoracic Rads - Abnormal Pseudocardiomegaly No significantly enlarged heart chambers Significantly enlarged cardiac silhouette Pericardial effusion Hemorrhage – HBT or ruptured LA Right heart failure – modified transudate Infectious pericarditis Idiopathic pericarditis Peritoneopericardial Diaphragmatic Hernia Pericardial fat

Thoracic Rads - Abnormal Case #2 – 15 month Maine coon cat – tachypnea, lethargy 5.1 + 3.5 = 8.5

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 Cardiac silhouette Generalized cardiomegaly, apex shifted right

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 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 Case #3 – 12 year old Mini Poodle - holosystolic murmur L apex

Thoracic Rads - Abnormal Case #3 – 12 year old Mini Poodle - holosystolic murmur L apex

Thoracic Rads - Abnormal Case #3 – 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 (13) VHS high normal (10.5) if you exclude LA Huge LA No signs of congestive heart failure

Thoracic Rads - Abnormal Case #3 – 12 year old Mini Poodle - holosystolic murmur L apex Diagnosis Mitral regurgitation Treatment Cough suppressants Monitoring Chest rads every 6 months Sooner if respiratory rate while sleeping >35-40 (no echocardiogram)

Thoracic Rads - Abnormal Case #3 – 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 CHF is rarely present without a murmur Dogs with MR can cough without CHF

Thoracic Rads - Abnormal

Thoracic Rads - Abnormal 3 Most Common Causes of L Heart Enlargement in the Dog MR PDA SAS

Thoracic Rads - Abnormal Case #5 – 4 year old DSH - Murmur heard on annual – left sternum 4 + 3.5 = 7.5

Thoracic Rads - Abnormal Case #4 – 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

Thoracic Rads - Abnormal Case #4 – 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 Many cats w/ severe heart disease have normal VHS

Thoracic Rads - Abnormal Case #5 – 5 month Golden Retriever - Episodes of collapse with exercise

Thoracic Rads - Abnormal Case #5 – 5 month Golden Retriever - Episodes of collapse with exercise

Thoracic Rads - Abnormal Case #5 – 5 month 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 & small LA bulge on lateral No signs of congestive heart failure Echo diagnosis – severe SAS

Thoracic Rads - Abnormal Loss of Cranial Waste Dilated Aortic Arch SAS PDA Tetralogy of Fallot Enlarged RAuricle TR Heartworm Disease Heart Base Tumor (RA, Aortic Body) HSA, chemodectoma, myxosarcoma

Thoracic Rads - Abnormal Case #6 – 12 yr old Mixed Terrier - Chronic cough and cyanosis

Thoracic Rads - Abnormal Case #6 – 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 #6 – 12 yr old Mixed Terrier - Chronic cough and cyanosis Echo diagnosis RV thickening Suspect pulmonary hypertension Clinical Diagnosis Severe chronic pulmonary disease

Thoracic Rads - Abnormal Case #6 – 12 yr old Mixed Terrier - Chronic cough and cyanosis What does it mean when the apex is shifted right on the VD? LV enlargement or generalized cardiomegaly What does it mean when the apex is shifted left on the VD? RV enlargement

Thoracic Rads - Abnormal Case #6 – 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 3.0 / 1.1 = 2.73 Measuring RV enlargement on Lateral View of the Thorax

Thoracic Rads - Abnormal 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 <2.5x Caudal in normal dogs (Cr >2.5x Cd) means RV enlargement

Thoracic Rads - Abnormal Case #7 – 10 month old Chihuahua Ejection murmur loudest at heart base on left side

Thoracic Rads - Abnormal Case #7 – 10 month old Chihuahua Ejection murmur loudest at heart base on left side

Thoracic Rads - Abnormal Case #7 – 10 month old Chihuahua Ejection murmur loudest at heart base on left side Skeletal, Cranial Abdomen, Airways, Lung fields, small vessels normal Great vessels - pulmonary artery enlarged Cardiac silhouette – apex shifted R, RV & RAu enlargement, VHS 8.25 No signs of Congestive Heart Failure

Thoracic Rads - Abnormal Case #7 – 10 month old Chihuahua Ejection murmur loudest at heart base on left Causes of enlarged MPA (dogs) PS (RPA, LPA, lobar aa/vv not enlarged) PDA (lungs overcirculated – lobar aa and vv enlarged, but not tortuous) Pulmonary hypertension (RPA, LPA lobar aa enlarged) MPA enlargement Not easily seen on lateral in dogs, but sometimes is not readily seen in cats This case – echo diagnosis PS – need spectral Doppler to measure gradient across RV thickening, MPA enlargement

Thoracic Rads - Abnormal LPA, RPA, lobar aa enlarged and tortuous Pulmonary Hypertension DDx HW Disease Primary PH Chronic Respiratory Disease

Thoracic Rads - Abnormal Case #8 – 6 month old poodle with mitral murmur found on physical exam

Thoracic Rads - Abnormal Case #8 – 6 month old poodle with mitral murmur found on physical exam

Thoracic Rads - Abnormal Case #8 – 6 month old poodle with mitral murmur found on physical exam Continuous murmur in the left armpit Echo Dx – PDA (with no CHF) Measuring pulmonary lobar arteries Caudal lobar aa should be same width as a rib Seen best on the VD/DV view cranial lobar aa 0.75x 3rd or 4th rib Seen best on the lateral view

Thoracic Rads - Abnormal Case #8 – 6 month old poodle with murmur found on physical exam Dx – PDA with no CHF Measuring pulmonary lobar arteries Caudal lobar aa should be same width as a rib Seen best on the VD/DV view cranial lobar aa 0.75x 3rd or 4th rib Seen best on the lateral view

Thoracic Rads - Abnormal Case #9 – 5 yr old DSH cat Tachypnea

Thoracic Rads - Abnormal Case #9 – 5 yr old DSH cat tachypnea Ascites in the cranial abdomen Perihilar edema HUGE Caudal Vena Cava Enlarged pulmonary lobar veins Elevated trachea (LV enlargement) Enlarged Lauricle on VD Marked generalized cardiomegaly (VHS 10.5)

Thoracic Rads - Abnormal Case #9 – 5 yr old DSH cat Tachypnea Enlarged Caudal vena cava -size varies with respiratory cycle -only severe enlargement is reliably detected -maximum width < length T5 or T6 Causes Right heart failure, Pericardial effusion Mass obstructing Caudal Vena Cava Thrombus, tumor

Thoracic Rads - Abnormal Case #9 – 5 yr old DSH cat Tachypnea

Thoracic Rads - Abnormal Case #10 – 2 yr old DSH cat Tachypnea

Thoracic Rads - Abnormal Case #10 – 2 yr old DSH cat Tachypnea VHS 7.5 - normal Left Heart Failure Patchy pulmonary edema (caudal) Pulmonary edema can take any pattern in the cat (perihilar, patchy, cotton-like, interstitial, alveolar, etc) Echo diagnosis – hypertrophic cardiomyopathy

Thoracic Rads - Abnormal Case #11 – 6 yr old Westie ADR

Thoracic Rads - Abnormal Case #11 – 6 yr old Westie ADR

Thoracic Rads - Abnormal Case #11 – 6 yr old Westie ADR VHS 7.75 (below normal) Clinical diagnosis – hypovolemia Causes of microcardia Severe dehydration Addison’s Disease Pneumothorax (heart lifted off the sternum) Should also see collapsed lung lobes

Thoracic Rads - Review Left Heart Failure Pulmonary edema (interstitial – mild: alveolar - severe) Pleural effusion in cats Pulmonary lobar veins much larger than arteries Enlarged LA + compression of L bronchus Not a sign of heart failure per se But LHF is rarely present without LA enlargement + Enlarged LV Tracheal elevation, axis shift right on VD 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) RHF alone DDx: HWDz, Chaga's Disease, pericardial disease, TR

Thoracic Rads - Review Chronic Bronchitis Crackles in small airways Increased or mineralized airway pattern Peribronchiolar infiltrates May progress to bronchopneumonia Airway pattern first Interstitial pattern as things progress Alveolar pattern (air bronchograms) if severe Signs of pulmonary hypertension Enlarged pulmonary artery and lobar aa Cough, cyanosis with 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 on rads Increased VHS Not as marked as volume overload Enlarged ascending aorta Left Heart Failure due to aortic insufficiency is rare Death more often due to arrhythmia

Thoracic Rads - Review Pulmonic Stenosis -pressure overload right side + Enlarged RV on rads Not as marked as volume overload Enlarged MPA Right Heart Failure due to pulmonic insufficiency is rare Death more often due to arrhythmia

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 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

(Radiograph Diagnostic Chart) 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 (Radiograph Diagnostic Chart)

Acknowledgements AAHA Cardiology Handbook Kittleson M Small Animal cardiovascular Medicine, Veterinary Information Network. Chapter 4 – radiography of the Cardiovascular System