Thoracic Imaging Review
Daniel A. Feeney, DVM, MS Professor of Veterinary Radiology Diplomate, American College of Veterinary Radiology Title: Imaging the Problem Coughing Patient Date: February, 2008
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
Technical Considerations • • • • •
Inspiration or PAIRED Inspiration/Expiration VD (preferred) or DV Right versus Left Lateral Views Right AND Left Lateral Views Included Anatomy: – Thoracic inlet Diaphragmatic Crura – Dog-O-Gram, Cat-O-Gram
• High kVp, Low mAs [long-scale contrast] Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Interpretive Considerations
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Etiologic Considerations • Gamut Considerations: – – – – – – – –
-D -A -M -N -I -T -V -P
(degenerative, developmental) (allergic, anomalous, agenesis) (metabolic) (neoplastic, nutritional) (inflammatory, infectious, immune-mediated) (traumatic) (vascular) (parasitic)
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Interpretive Considerations • Localizing the Disease:
• Spectrum of Disease:
– Nasal (obstruction [mass/FB], post nasal drip) – Pharynx (mass, FB, poor tone) – Larynx (mass, FB, vocal fold dysfunction, trauma) – Trachea (intra/extra-thoracic collapse, mass, FB) – Bronchi (bronchial disease, bronchiectasis, mass, FB) – Alveoli (material in air exchange spaces, atelectasis) – Interstitium (material [structured/unstructured] in stroma)
– Ventilation – Perfusion – Gas Exchange
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Silhouette Sign (B. Felson)
Overview Approach to the Thoracic Radiograph • Identify the Following: (cont.) – lungs all lobes ( note position and location of interlobar fissure lines if seen) – pulmonary vessels – paracardiac medistinum (check for masses and esophageal dilation) – heart and central great vessels (ascending aorta and pulmonary trunk) • right and left atria • right and left ventricles
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Overview Approach to the Thoracic Radiograph • Are There Any Masses or Abnormal Densities Not Localized to Specific Organs or Regions Previously Listed? • Formulate Rule-outs • Determine if More Imaging is Necessary
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Lung Patterns
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Causes of Dyspnea • Atelectasis (pneumothorax, pleural effusion, masses) • Airway obstruction, collapse • Primary pulmonary parenchymal disease • Ineffective ventilatory efforts (paralyzed diaphragm, flail chest) • Pulmonary disease secondary to heart disease (vascular embolism, congestion) Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Alveolar Patterns
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Alveolar Patterns Pathophysiology in Alveolar Disease: • Infiltrate of inflammation, allergic, hemorrhagic, aspirated, or edematous materials into the air-exchange spaces • Remember, atelectasis is a form of alveolar disease • Remember, emphysema and bullae are destroyed alveoli
Radiographic Appearance: • air-bronchogram • silhouette sign (only process that regularly does this) • ill-defined border within lobe • well-defined border at interlobar fissues Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Distribution: Alveolar Patterns Symmetrical Perihilar Ventral Caudodorsal Diffuse Lobar Random
UNIVERSITY OF MINNESOTA Veterinary Medical Center
******
Asymmetrical ******
pneumonia neurogenic edema hemorrhage, ARDS pneumonia, atelectasis hemorrhage hemorrhage, ARDS
UNIVERSITY OF MINNESOTA
Title: Thoracic Imaging Review Date: March, 2009
Interstitial Patterns
Title: Thoracic Imaging Review Date: March, 2009
cardiogenic edema hemorrhage, pneumonia neurogenic edema fluid overload, ARDS agonal edema
Veterinary Medical Center
Interstitial Patterns
UNIVERSITY OF MINNESOTA
Title: Thoracic Imaging Review Date: March, 2009
Veterinary Medical Center
Interstitial Patterns Pathophysiology in Alveolar Disease: • Infiltrate of inflammation, allergic, hemorrhagic, aspirated, or edematous materials into the lung stroma • Remember, partial atelectasis is a form of interstitial disease • Remember, emphysema and bullae are destroyed alveoli, but it is the interstitium that now contains the air
Radiographic Appearance: • structured (mass or nodules) or unstructured • NO air-bronchogram • NO silhouette sign • well-defined border within lobe if nodular or mass • “dirty windshield” appearance if unstructured Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Distribution: Interstitial Patterns Symmetrical Solitary Multifocal Unstructured
Asymmetrical
******
Mass (Ca), granuloma
mycotic, metastases fibrosis, age lymphangectatic mets
hemorrhage, ARDS
Lobar Random
Title: Thoracic Imaging Review Date: March, 2009
hypoinflation
COPD
******
pneumonia, atelectasis COPD, hypoinflation
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Upper Airway Dysfunction
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Central Airway Dysfunction
Upper Airway Dysfunction
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Intra-pulmonary Airway Dysfunction a.k.a. Bronchial Disease
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Bronchial Patterns
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Considerations: Bronchial Patterns
Pathophysiology in Bronchial Disease: • Infiltrate of inflammation or allergic processes or glandular hypertrophy + wall fibrosis • Adjust sensitivity of interpretation based on age (old animals have some normal bronchial prominence)
Radiographic Appearance:
Allergy/Antigen/Atopy Environment Age Effect Chronic Inflammation Resident or Migrating Lung Parasites
•“doughnuts” when viewed end-on •“cylinders”/”tramlines” when viewed from the side • Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Circulatory Dysfunction
Circulatory Dysfunction
Lobar Vein Enlargement
Lobar Artery Enlargement, Distortion, Truncation
artery bronchus vein
Canine Heartworm Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Tension Pneumothorax
Circulatory Dysfunction Lobar Artery Enlargement, Distortion, Truncation….
Feline Heartworm Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
Pneumomediastinum
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Etiology of Pleural Effusion • Appearance non-specific • Seek clues in rest of film: – – – – – –
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Cardiomegaly Mediastinal mass Aggressive rib lesion Evidence of trauma Ascites Abdominal visceral displacement
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Radiographic Signs of Pleural Fluid
Pleural Effusion
• Fissure lines between lobes • Displacement of periferal lung borders from internal rib margins, sternum, spine • Blunted costophrenic angle • Moves with gravity • Beware of chondystrophoid breeds and fat cats
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Contributing FactorsCough [non-respiratory] •Airway Compression Turbulence: -retropharyngeal/mediastinal masses -head/neck/intrathoracic fat •Body Habitus: -obesity effect on respiratory effort •Restraint Apparatus: -collar •Breed Risk: -toy breeds Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Follow-up Considerations • Routine Diagnostic Techniques: – – – – – – –
CBC (? systemic allergic or inflammatory reaction) Fecal Exam (resident or migrating lung parasites) Heartworm Check (multiple, antigen vs. antibody) Pulse Oximetry Arterial/Venous Blood Gas Analyses Trans-tracheal Wash [alveolar and bronchial only] Trans-thoracic, Fine-needle Aspiration [alveolar and interstitial only]
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Interpretive Considerations • Defining Non-pulmonary Factors: – Heart and Great Vessels: • Airway compression or distortion
– Lung Vessels: • Circulatory disturbances Parenchymal Reactions
– Esophagus: • Airway compression or distortion • Aspiration tracheitis pneumonia • Acid reflux Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Follow-up Considerations • Spohisticated/InvasiveTechniques: – Fluoroscopy [dynamic observation] – Bronchoscopy, BAL, Brush Biopsy…. – Computed Tomography – Magnetic Resonance Imaging – Scintigraphic Perfusion Studies – Scintigraphic Ventilation Studies Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Caveats/Considerations-Coughing • Upper Airway Disease (nasaltracheal): – Remember the interaction among segments: • Nasal obstruction influences pharyngeal diameter • Pharyngeal dysfunction may influence laryngeal migration • All airways above the trachea influence its respiratory dynamics
• Lower Airway Disease (bronchi): – Remember the continuum or pathophysiology • Bronchial disease can be the cause of or the result of coughing • Unmanaged bronchial disease… bronchiectasisrecurring pneumonia
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Caveats/Considerations-Coughing • Interstitial Parenchymal Disease: – Remember the interstitium is the “conduit” • Alveolar disease is preceded by and followed by it • Can be difficult to distinguish severe bronchial-associated interstitial reaction from metastatic disease • Interstitial disease does not exfoliate
• Alveolar Parenchymal Disease: • Pattern recognition and distribution are the keys – Modified by history and other clinical findings – Modified by assessment of heart size, lung vessel appearance
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Cough/Gag
Pharyngeal Collapse
expiration/inspiration
expiration/inspiration
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Hacking Cough
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA Veterinary Medical Center
Tracheal Collapse
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Rapid Shallow Breathing/Coughing
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Coughing and Tachypnea
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Coughing (dry) with Intermittent Dyspnea
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Over Inflated Lungs PyogranulomatousTracheitis
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Mediastinal Mass
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Bronchial Disease (Asthma)
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Coughing, Gagging, Regurgitating
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Chronic Cough (for years)
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Hacking Cough (known Tracheal collapse)
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Pneumonia [secondary to esophageal disease]
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Patchy Emphysema (COPD)
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Esophageal FB
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Bronchoesophageal Fistula
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Post-trauma, Unexplained Dyspnea and Coughing
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Chronic Cough
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Bronchoesophageal Fistula
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Paralyzed Diaphragm
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Bronchiectasis
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Septic, Progressive Dyspnea
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Coughing, Exercise Intolerance
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
ARDS
UNIVERSITY OF MINNESOTA
Title: Thoracic Imaging Review Date: March, 2009
College of Veterinary Medicine
Heartworm Disease
UNIVERSITY OF MINNESOTA
Title: Thoracic Imaging Review Date: March, 2009
References: THORAX
College of Veterinary Medicine
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In addition to the Thrall Text, consider the following: FelsonB. Chest Roentgenology. WB Saunders, Philadelphia, 1973. Burk RL, Feeney DA: Small Animal Radiology and Ultrasonography. Saunders/Elsevier, Philadelphia, 2003 Suter PF and Kam CF: Disseminated pulmonary diseases in small animals: a radiographic approach to diagnosis. Vet Radiol Ultrasound 1968;9:67-79. Groskin SA: Heitzman's the Lung: Radiologic Pathologic Correlations which is in the Veterinary Library TC Veterinary Medical Library RC734.R3 H45 1993. Felson B. Chest Roentgenology (full citation in your lecture notes at the end).
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
Title: Thoracic Imaging Review Date: March, 2009
UNIVERSITY OF MINNESOTA College of Veterinary Medicine
