Cardiovascular Radiography Notes 2025 PDF

Cardiovascular Radiography Goals Define cardiac silhouette Identify the region of the cardiac chambers, structures and pulmonary vessels in thoracic radiographs Know the anatomical differences of the cardiac silhouette and chamber in cats vs. dogs Perform a VHS Recogniz...

Cardiovascular Radiography Goals Define cardiac silhouette Identify the region of the cardiac chambers, structures and pulmonary vessels in thoracic radiographs Know the anatomical differences of the cardiac silhouette and chamber in cats vs. dogs Perform a VHS Recognize the normal radiographic appearance of the cardiac silhouette Be able to evaluate abnormal heart size and chamber enlargement Recognize common abnormalities of the cardiac silhouette Be familiar with the most common acquired and congenital cardiovascular diseases Review of the “Normals” Cardiac silhouette Heart + Pericardial sac Border effacement Cannot differentiate heart from pericardium on radiographs – BORDER EFFACEMENT Cardiac Silhouette Large variation in normal Inherently variable due to function Considerable breed variation Bulldog Doberman  Schematic of Ao = Aortic arch heart chambers BR = Brachiocephalic trunk CdVC = Caudal vena cava CrVC = Cranial vena cava IT = Internal thoracic arteries & veins, cranial mediastinal reflection LA = Left atrium LAu = Left auricular appendage LPA = Left pulmonary artery LS = Left subclavian artery LV = Left ventricle MPA = Main pulmonary artery RA = Right atrium Rau = Right auricular appendage RPA = Right pulmonary artery RV = Right ventricle Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89  Schematic of heart chambers Ao = Aortic arch BR = Brachiocephalic trunk CdVC = Caudal vena cava CrVC = Cranial vena cava LA = Left atrium (sort of) LAu = Left auricular appendage LS = Left subclavian artery LV = Left ventricle MPA = Main pulmonary artery RA = Right atrium Rau = Right auricular appendage RV = Right ventricle Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Clock Face Analogy This has been used to identify specific chamber locations on a radiograph The clock numbers are used to indicate approximate position of the chambers and great vessels Lateral VD/DV view 12:00-2:00 LA 11:00-1:00 Ao 2:00-5:00 LV 1:00-2:00 MPA 5:00-9:00 RV 2:00-3:00 LAu 2:00-5:00 LV 5:00-9:00 RV 9:00-11:00 RA  Cardiac Chamber Evaluation AA: 11:00 – 1:00 MPA: 1:00 – 2:00 RA: 9:00 – 11:00 GV LA LAu: 2:00 – 3:00 RA LA RV: 5:30 – 9:30 LV RV LV: 3:00-5:00 DV view Aortic arch (11-1 o’clock) Descending aorta Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 DV view Main pulmonary artery (1-2 o’clock) Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 DV view Left auricle (2:00-3 o’clock) Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Cardiovascular system – right lateral L atrium 12:00-2:00 LA 2:00-5:00 LV 5:00-9:00 RV Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 DV view Left atrium Cardiovascular system – right lateral L ventricle 12:00-2:00 LA 2:00-5:00 LV 5:00-9:00 RV Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 DV view Apex of heart lies left of midline Left ventricle (2-5 o’clock) Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Cardiovascular system – right lateral R ventricle 12:00-2:00 LA 2:00-5:00 LV 5:00-9:00 RV Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Cardiovascular system – DV view Right ventricle (5 - 9 o’clock) Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Cardiovascular system – right lateral R ventricle 12:00-2:00 LA 2:00-5:00 LV 5:00-9:00 RV 10:00-11:00 RA Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Cardiac anatomy – DV view Right atrium (9 – 11 o’clock) Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Atrial location in Cats Cardiovascular system – left lateral  Cranial vena cava DV view in the cranial mediastinum with other structures Caudal vena cava passing through caval foramen Schwartz T, Johnson V. BSAVA Manual of Canine and Feline Thoracic Imaging. Chapter 7: Heart and major blood vessels. Pg 89 Caudal Vena Cava & Diaphragmatic Crura Right cranial pulmonary vessels - lateral view Right cranial pulmonary artery Right cranial lobar bronchus Right cranial pulmonary vein Pulmonary veins are ventral (lateral views) and central (DV/VD views) Caudal lobe pulmonary vessels - DV Pulmonary artery Pulmonary vein 9th Rib Pulmonary veins are ventral (lateral views) and central (DV/VD views) Cardiovascular interpretation  Cardiovascular interpretation Evaluation of the heart 1. Subjectively evaluate size, shape, margination and opacity 2. Try to identify the cardiac margins separately from the adjacent fat (*cats) 3. Cardiac silhouette size and shape inherently variable between species and (dog) breeds, and considering the different phases of the cardiac cycle Cardiovascular interpretation Three basic questions… 1. Is the heart size normal? 2. Is/are there specific cardiac chamber enlargement (and which ones)? 3. Is there evidence of heart failure? Left or right-sided? Both? Dog Breed Variation Cardiac Size Evaluation (DOGS) Lateral 2.5 – 3.5 intercostal spaces wide Breed variation VD Half to two-thirds width of thorax Cardiac Size Evaluation Vertebral Heart Scale T4 (VHS) Length Carina to Apex Width Perpendicular to length Widest point At level of CVC Measure L & W along vertebra starting at T4 Cardiac Size Evaluation Normal VHS Values: Dogs: 9.7+/- 0.5* * Breed variation: up to 12.7 reported as normal in dogs Cardiac Size Evaluation – Newer methods Vertebral Left Atrial Size (VLAS) T4 Length of the LA Carina to CdVC Vertebral measurement Starts at the cranial portion of T4 Good correlation with the VHS Normal range = 1.4 - 2.2 v Average = 1.9 v Cardiac Size Evaluation – Newer methods Modified Vertebral Left Atrial Size (M-VLAS) T4 Similar as the VLAS measurement + perpendicular line Height of the LA Vertebral measurement Starts at the cranial portion of T4, twice Sum the measurements M-VLAS is superior to VHS to identify LA enlargement in dogs with MMVD Cut off value ≥ 3.4 v How about cats? Cardiac Evaluation: Cats Be aware: Pericardial Fat Can Mimic Cardiomegaly! 39 Cardiac Size Evaluation (CATS) Lateral 2.0 -2.5 intercostal spaces wide on lateral Measure perpendicular to line linking apex and base because of tilt VD ½ to ⅔ the width of thorax Feline Vertebral Heart Score (VHS) Length Tracheal bifurcation to the cardiac apex Width Perpendicular to the length Widest point Measure L and W along the vertebrae, starting at T4 VHS = Total number of vertebral bodies the lines cover Normal VHS in Cats = 7.5 +/- 0.3 v Cardiac Evaluation: CATS Clock face analogy does not work well in cats Determine specific chamber enlargement is difficult Focus more on shape! Cardiomegaly Normal Cardiac Evaluation: CATS VD or DV projection: Valentine-shaped heart Bi-atrial or severe left atrial alone Cardiac Size Evaluation (CATS) Increasing tilt with age “Lazy Heart” Care when measuring Redundant aorta “Aortic knob” 30-40% of cats 10-15 years old Normal geriatric feline thorax Normal non- geriatric  Radiographic Interpretation of the Pulmonary Arteries and Veins Pulmonary Vessels Cranial lobar vessels: best visualized on lateral projections Caudal lobar vessels: best visualized on DV / VD Size Lateral projection – dorsal portion of 4th rib VD or DV – cross 9th rib (or 10th rib) Pulmonary Vasculature: Measurements Left Lateral Projection RIB 4 Dorsal 1/3 Pulmonary Vasculature: Measurements Dorsoventral Projection RIB 9  Pulmonary Vasculature Enlarged pulmonary arteries and veins (overcirculation) Left to right shunting defect Arteriovenous fistula Overhydration 51 CHF - cats 51  Pulmonary Vasculature Enlarged pulmonary arteries Heartworm disease Pulmonary hypertension 52 52  Pulmonary Vasculature Enlarged pulmonary veins Left-sided cardiac failure 53 53 Cardiac Chamber Enlargement Left vs Right Cardiomegaly (tall vs. wide) Radiographic signs of left atrial enlargement Lateral projections: - “Back pack sign” Radiographic signs of left atrial enlargement VD/DV projections: - “Bow-legged cowboy sign” Radiographic signs of left auricular enlargement - Only seen in cases of at least moderate LA enlargement - VD/DV projection: bulge at 2-3 o’clock  Radiographic signs of left ventricular enlargement - Not very sensitive - Usually not alone (concurrent LA enlargement) - Lateral projections: - Elongation of the cardiac silhouette (height), with dorsal displacement of the trachea Radiographic signs of left ventricular enlargement - Not very sensitive - Usually not alone (concurrent LA enlargement) - VD projection: - Rounding or blunting of the cardiac apex Severe Left-sided Cardiomegaly Radiographic signs of right-sided cardiomegaly (in theory…) Right atrial Right ventricular enlargement enlargement Right-sided cardiomegaly Thoracic radiographs should be used with caution for the evaluation of cardiac chamber enlargement, particularly in the presence of severe left-sided cardiomegaly Radiographic signs of right-sided cardiomegaly - More difficult to distinguish if the enlargement of atrial, auricular, ventricular or both in origin - Lateral projections: - Widening of the cardiac silhouette (> 3.5 ICS) - Increased sternal contact * Radiographic signs of right-sided cardiomegaly - VD projection: - Rounding of the right aspect of the cardiac silhouette - Displacement of the cardiac apex to the left - “Inverted D” appearance - Overdiagnosed… Radiographic signs of right-sided cardiomegaly - VD projection: - Focal enlargement of the main pulmonary artery (MPA) - Bulge at 1-2 o’clock - Usually concurrent with an “Inverted D” appearance of te cardiac silhouette Generalized cardiomegaly - Cardiac and/or pericardial origin - Cardiac - Concurrent left and right cardiomegaly - Complex congenital defects - Mitral and tricuspid valvular degeneration - Pericardial - Effusion - PPDH Generalized cardiomegaly: Left and right sided - Specific bulges CAN be identified Generalized cardiomegaly: Pericardial Effusion - GLOBOID cardiac silhouette - May develop cardiac tamponade - Right-sided cardiac failure - Neoplasia is the most common cause in dogs: - Right auricular hemangiosarcoma - Heart base mass - chemodectoma Generalized cardiomegaly: PPDH - Common type of congenitally predisposed hernia - Abdominal structures into the pericardial sac - Enlarged cardiac silhouette with mixed opacities - Often an incidental finding in young dogs and cats Microcardia - Less than 2 ICS on the lateral projections - Concurrent small pulmonary vasculature and CVC - DDx: - Hypoadrenocorticism (Addison’s disease) - Hypovolemia Heart failure: Is not the same as cardiomegaly!! Congestive heart failure - Table Signs of left-sided CHF Left-sided cardiac enlargement Pulmonary venous congestion Cardiogenic pulmonary edema Perihilar and caudodorsal distribution (in cases of mitral valve insufficiency) In CATS: Pleural effusion Pulmonary edema - wherever it wants No need of cardiomegaly! Signs of left-sided CHF Enlargement of the pulmonary veins Signs of left-sided CHF Cardiogenic Edema - Unstructured interstitial to alveolar pattern - Peri-hilar and/or caudodorsal distribution (valvular disease) Signs of right-sided CHF Hepatic congestion Peritoneal Effusion Pleural Effusion Example: Left and Right Cardiomegaly with Right-sided Cardiac Failure Review of Heart Failure in Cats Pulmonary venous +/- arterial enlargement: Left Pulmonary Edema (any distribution): Left Pleural Effusion: Left or Right Peritoneal Effusion: Right Left CHF (Cat) Example of Left-sided Cardiac Failure in a Cat Congestive heart failure - Table Differentials for Cardiac Disease Left Sided Cardiomegaly Differential Diagnoses Acquired: Congenital: Mitral valve degeneration Patent ductus arteriosus Cardiomyopathy Sub-aortic stenosis Hypertrophic Mitral dysplasia cardiomyopathy (cats) Shunting defects Endocarditis Etc… Right Sided Cardiomegaly Differential Diagnoses Acquired: Congenital: Tricuspid valve Tricuspid dysplasia degeneration Pulmonic stenosis Cardiomyopathy Tetralogy of Fallot Heartworm disease Shunting defects Cor pulmonale Etc… Selected Acquired and Congenital Cardiac Diseases Common Cardiovascular Diseases Atrioventricular Valvular Regurgitation Myxomatous Degeneration Mitral, Tricuspid Cardiomyopathies Hypertrophic - HCM (Cat*) Dilated – DCM (Dog) Restrictive – RCM (Cat*) Arrhythmogenic Right Ventricular - ARVC (Boxer) And others… Hypertension Pulmonary Systemic  Mitral valve degeneration Most common cardiac disease in dogs!! - Adult small breed dogs Radiographic Findings - Enlargement of the left side of the heart - Initially LA and LAu, later LV - Dilated pulmonary veins - Congestion - Lead to left-sided heart failure - Cardiogenic edema Mitral valve degeneration  Cardiomyopathies (CM) Myocardial dysfunction - Decreased contractility - Myocardial hypertrophy - Adult large and giant breed dogs - Cats Radiographic Findings - Enlargement of the left atrium - +/- enlargement of the LV and right- sided chambers - Depending of the pathophysiology of the CM - Dilated pulmonary veins - Congestion - Lead to left-sided heart failure - Cardiogenic edema Dilated Cardiomyopathy 92 Hypertrophic Cardiomyopathy Hypertrophic Cardiomyopathy  Canine Heartworm Disease Radiographic Findings - MPA bulge - Right-sided cardiomegaly - Dilated and tortuous pulmonary arteries +/- mineralizations - Bronchial and unstructured interstitial pattern - +/- Right-sided cardiac failure Canine Heartworm Disease  Congenital Cardiac Diseases Congenital Defects Shunting defects -Abnormal communications Stenotic/dysplastic defects -Valvular and perivalvular Young patients  Patent Ductus Arteriosus - Communication of the aorta and MPA - Left to right * - Right to left (less common) – pulmonary hypertension - Classic finding: - “Three knuckles sign”: AA, MPA, LAu - Ductus diverticulum bulge - Left-sided cardiomegaly - Pulmonary overcirculation: - Enlarged veins and arteries Left-to-Right PDA Left-to-Right PDA Left-to-Right PDA – after treatment Septal defect (ventricular and atrial) - Initially Left to right * - NO Ductus diverticulum enlargement - Pulmonary overcirculation: - Enlarged veins and arteries - Uni or bilateral heart enlargement and secondary failure - VSD: Most common cardiac congenital defect in cats Left-to-Right VSD in a Cat  Pulmonic Stenosis (PS) - Enlargement of the MPA - Turbulent flow - May have small pulmonary arteries and veins (pulmonary undercirculation) - Right-sided cardiomegaly due to right ventricular enlargement - If mild, may have normal thoracic radiographs Pulmonic Stenosis (PS) Treatment: Balloon Valvuloplasty  (Sub)aortic Stenosis (SAS, AS) - Fibrous band at the LV outflow track and/or valvar thickening/hypomotility - Enlargement of the aortic arch - Turbulent post-stenotic flow - Left-sided cardiomegaly (Sub)aortic Stenosis (SAS, AS) Mitral/Tricuspid Valve Dysplasia Mitral dysplasia - Similar findings as mitral or tricuspid valve degeneration - Enlargement of the left and right Tricuspid dysplasia side of the heart, respectively - Young patients Complex Congenital Cardiac Defects - Tetralogy of Fallot: - Pulmonic Stenosis (PS) - Ventricular Septal Defect (VSD) - Misplaced aorta (to the right) - Right ventricular hypertrophy - Radiographic findings: - Boot-shaped heart (VD projection) - Pulmonary undercirculation - Small pulmonary vessels - Pentalogy of Fallot - Tetralogy +ASD - Cor Triatriatum - Dexter** or sinister - 3 atria (one is a blind sac) - Enlargement of the CVC and peritoneal effusion Tetralogy of Fallot Equine Corner Equine Thoracic Radiography Usually 4 different projections in an adult horse –Cranioventral, cranio-dorsal, caudoventral and caudodorsal (14 x 17” cassettes) May take both right and left lateral projections No DV or VD Equine Thoracic Radiography Equine Thoracic Radiography Determination of cardiac size is difficult: lack of objective criteria and inability to obtain orthogonal radiographs Straightening of caudal aspect of the heart Increased sternal contact and diaphragmatic contact Dorsal displaced trachea Echocardiography: best test Questions