PART 3
RADIOGRAPHIC AND ULTRASONOGRAPHIC SIGNS

3.1 Thoracic radiography

3.1.1 Artefactual causes of increased lung opacity

• Chemical stains/dirty cassettes
• Dirty or wet fur
• Forelimbs not pulled sufficiently forwards
• Movement blur
• Obesity
• Poorly inflated lungs
  • Abdominal distension
  • Expiratory film
  • Upper airway obstruction
• Underdevelopment
• Underexposure

3.1.2 Increased bronchial pattern

Normal variation*

• Chondrodystrophic breeds
• Older dogs

Bronchial wall oedema, e.g.

• Congestive heart failure*

Bronchiectasis

Chronic bronchitis*

• Primary ciliary dyskinesia (D)

Endocrine

• Hyperadrenocorticism

Infection

• Bacterial*
• Fungal, e.g.
  • Pneumocystis carinii
• Parasitic, e.g.
  • Crenosoma vulpis (D)
• Protozoal, e.g.
  • Toxoplasmosis
• Viral

Inflammation, e.g.

• Eosinophilic bronchopneumopathy (pulmonary infiltrate with eosinophilia) (D)
• Feline asthma (C)
• Idiopathic

Neoplasia

• Bronchogenic carcinoma
• Lymphoma

3.1.3 Increased alveolar pattern

Atelectasis

• Airway obstruction
• Chronic pleural or pulmonary disease*
• Collapse of the lung lobes under general anaesthesia*
• Extra-pulmonary thoracic mass
• Feline asthma* (C)
• Lack of surfactant (newborn, acute respiratory distress syndrome)
• Lung lobe torsion
• Pleural effusion* q.v.
• Pneumothorax* q.v.
• Recumbency

Inflammation/immune mediated

• Eosinophilic bronchopneumopathy (pulmonary infiltrate with eosinophilia)

Neoplasia

• Malignant histiocytosis
• Primary lung tumour, e.g.
  • Bronchoalveolar carcinoma
• Pulmonary lymphomatoid granulomatosis

Pneumonia

Aspiration pneumonia

• Aspirated foreign body*
• Aspirated secretions
• Cleft palate
• Gastrobronchial fistula
• Generalised weakness
• Iatrogenic, e.g.
  • Anaesthetic complication
  • Force feeding
  • Incorrectly placed stomach tube
• Oesophagotracheal/bronchial fistula
• Regurgitation, e.g.
  • Megaoesophagus
• Swallowing disorders
• Vomiting

Bronchopneumonia, e.g.

• Canine distemper virus with secondary bacterial infection* (D)
• Tracheobronchitis*

Bacterial, e.g.

• Tuberculosis
• Tularaemia

Fungal, e.g.

• Pneumocystis carinii

Parasitic, e.g.

• Aelurostrongylus abstrusus (C)
• Angiostrongylus vasorum (D)
• Dirofilaria immitis
• Oslerus osleri (D)

Miscellaneous

• Kartagener's syndrome
• Primary ciliary dyskinesia
• Radiation therapy

Pulmonary haemorrhage

• Coagulopathy q.v.
• Exercise induced
• Idiopathic
• Neoplasia*
• Trauma*

Pulmonary oedema

• Acute dyspnoea in Swedish hunting dogs
• Acute pancreatitis*
• Airway obstruction
• Brain trauma
• Congestive heart failure*
• Electrocution
• Hypoalbuminaemia
• Hypostatic congestion*
• Iatrogenic
  • Aspirated hypertonic contrast media
  • IV contrast media
  • Over-hydration
• Inhalation of irritant gases/smoke
• Lung lobe torsion
• Near drowning
• Obstruction of pulmonary drainage mechanisms, e.g.
  • Hilar mass
• Post-ictal
• Re-expansion, e.g.
  • Post pneumothorax
• Seizures
• Other CNS disease
• Uraemia q.v.

Acute respiratory distress syndrome

• Iatrogenic, e.g.
  • Over-hydration
  • Oxygen therapy
• Infection
• Inhalation pneumonia
• Pancreatitis
• Trauma

Toxins

• Alpha-napthylthiourea
• Endotoxin
• Ethylene glycol
• Paracetamol
• Snake venom

Pulmonary thromboembolism

3.1.4 Increased interstitial pattern

Nodular

Artefact

• End-on view of blood vessels
• Nipples
• Objects adhering to coat
• Ossification of costochondral junctions
• Thoracic wall nodules

Infection

• Abscesses
• Feline infectious peritonitis* (C)
• Granulomata
  • Bacterial
  • Foreign body*
  • Fungal
• Hydatid cysts
• Parasitic
  • Aelurostrongylus abstrusus (C)
  • Crenosoma vulpis (D)
  • Oslerus osleri (D)
  • Paragonimus kellicotti (D)
  • Tularaemia
  • Visceral larva migrans
• Pneumonia
  • Fungal pneumonia
  • Haematogenous bacterial pneumonia
  • Mycobacterial pneumonia
• Protozoal, e.g.
  • Toxoplasmosis

Neoplasia

• Lymphoma*
• Metastatic tumours*
• Primary lung tumours

Miscellaneous

• Calcified pleural plaques*
• Disseminated intravascular coagulation
• Haematomata
• Idiopathic mineralisation
• Pulmonary osteomata (heterotopic bone)*

Diffuse/unstructured

• Artefact, e.g.
• Expiratory film
• Neoplasia
• Oedema (early) q.v.

Drugs/toxins

• Chronic glucocorticoid administration
• Paraquat

Endocrine

• Hyperadrenocorticism

Infection

• Bacterial
• Fungal, e.g.
  • Blastomycosis
  • Coccidioidomycosis
  • Cryptococcosis
  • Histoplasmosis
  • Pneumocystis carinii (D)
• Mycoplasmosis
• Parasitic
  • Aelurostrongylus abstrusus (C)
  • Angiostrongylus vasorum (D)
  • Babesiosis
  • Dirofilariasis
• Protozoal, e.g.
• Rickettsial, e.g.
  • Rocky Mountain spotted fever (D)
• Toxoplasmosis
• Viral, e.g.
  • Canine distemper virus* (D)
  • Feline infectious peritonitis* (C)

Inhalation

• Dust
• Irritant gases

Miscellaneous

• Acute respiratory distress syndrome
• Pancreatitis
• Pulmonary thromboembolism
• Radiation therapy
• Uraemia* q.v.
• Very old animals
• Very young animals

Pulmonary fibrosis

• Idiopathic
• Secondary to chronic respiratory disease

Pulmonary haemorrhage

• Coagulopathy q.v.
• Exercise induced
• Idiopathic
• Neoplasia
• Trauma

Reticular pattern

• Normal ageing*
• Chronic fibrosis
• Fungal pneumonia
• Lymphoma*
• Metastatic neoplasia*

3.1.5 Increased vascular pattern

Increased size of pulmonary arteries

• Aelurostrongylus abstrusus (C)
• Angiostrongylus vasorum (D)
• Dirofilariasis
• Large left-to-right shunts, e.g.
  • Atrial septal defect
  • Endocardial cushion defects
  • Patent ductus arteriosus
  • Ventricular septal defect
• Pulmonary hypertension
• Pulmonary thromboembolism

Increased size of pulmonary veins

• Left-sided heart failure*
• Left-to-right shunts, in some cases

Increased size of pulmonary arteries and veins

• Left-to-right shunts, e.g.
  • Atrial septal defect
  • Endocardial cushion defects
  • Patent ductus arteriosus
  • Ventricular septal defect

3.1.6 Decreased vascular pattern

Generalised

Pericardial disease, e.g.

• Pericardial effusion* q.v.
• Restrictive pericarditis

Pulmonary hypoperfusion

• Hypoadrenocorticism (D)
• Localised hypoperfusion due to pulmonary thromboembolism
• Pulmonic stenosis
• Severe dehydration*
• Shock*
• Tetralogy of Fallot

Pulmonary overinflation

• Air trapping
  • Chronic bronchitis* (D)
  • Feline asthma* (C)
  • Upper respiratory tract obstruction, e.g.
    • Foreign body*
    • Nasopharyngeal polyp* (C)
• Compensatory
  • Following lobectomy
  • Secondary to atelectasis of another lobe
  • Secondary to congenital lobar atresia/agenesis
• Emphysema
• Iatrogenic
  • Anaesthesia

Right-to-left cardiac shunts, e.g.

• Atrial septal defect
• Reverse-shunting patent ductus arteriosus
• Tetralogy of Fallot
• Ventricular septal defect

Localised

• Emphysema
• Pulmonary thromboembolism

3.1.7 Cardiac diseases that may be associated with a normal cardiac silhouette

• Bacterial endocarditis
• Congestive heart failure overzealously treated with diuretics
• Constrictive pericarditis
• Functional murmurs*
• Hypertrophic cardiomyopathy* (C)
• Neoplasia
• Small atrial septal defect
• Small ventricular septal defect

3.1.8 Increased size of cardiac silhouette

Generalised cardiomegaly

• Normal variation, e.g.
• Greyhound*
• Artefact
• Bacterial endocarditis
• Bradycardia* q.v.
• Chronic anaemia* q.v.
• Concurrent mitral and tricuspid valve deficiency
• Dysplasia
• Intrapericardial fat
• Mediastinal fat
• Myxomatous degeneration* (D)
• Congenital cardiac disease, e.g.
  • Peritoneopericardial diaphragmatic hernia
• Enlargement of specific chamber sizes q.v.
• Pericardial effusion* q.v.

Myocardial disease

• Inflammatory
  • Immune mediated, e.g. rheumatoid arthritis
  • Infectious, e.g.
    • Bacterial
    • Fungal
    • Parvovirus
    • Protozoal
• Ischaemic
  • Arteriosclerosis
• Noninflammatory
  • Dilated cardiomyopathy*
  • Hypertrophic cardiomyopathy (C)*
  • Restrictive cardiomyopathy (C)
• Secondary
  • Acromegaly
  • Amyloidosis
  • End-stage mitral valve insufficiency* (D)
  • Glycogen storage disease
  • Hypertension* q.v.
  • Hyperthyroidism* (C)
  • Mucopolysaccharidosis
  • Neoplasia
  • Neuromuscular disease
  • Nutrition
    • l-Carnitine deficiency
    • Taurine deficiency
  • Trauma
  • Drugs/toxins
    • Doxorubicin
    • Heavy metals

Volume overload

• Iatrogenic
• Left-sided heart failure
  • Bacterial endocarditis
  • Dilated cardiomyopathy*
  • Mitral valve dysplasia
  • Myxomatous degeneration of the mitral valve* (D)

3.1.9 Decreased size of cardiac silhouette

• Atrophic myopathies
• Constrictive pericarditis
• Hypoadrenocorticism (D)
• Post thoracotomy

Artefact

• Deep-chested dogs
• Deep inspiration
• Heart displaced from sternum, e.g.
  • Mediastinal shift
  • Pneumothorax
• Pulmonary overinflation, e.g.
  • Emphysema
  • Hyperventilation

Decrease in muscle mass

• Chronic systemic disease
• Malnutrition
• Myopathies

Shock* q.v., e.g.

• Hypovolaemia, e.g.
  • Blood loss
  • Severe dehydration

3.1.10 Abnormalities of the ribs

Congenital disorders

• Absence of the xiphisternum
• Agenesis/hypoplasia of the 13th rib*
• Pectus excavatum
• Supernumerary ribs

New bone

• Cartilaginous exostoses
• Healed fractures
• Mineralisation of the costal cartilages*
• Neoplasia
• Non-union fractures
• Periosteal reaction to soft tissue mass

Osteolysis

• Metastatic tumours
• Osteomyelitis
• Primary tumours
  • Chondrosarcoma
  • Fibrosarcoma
  • Haemangiosarcoma
  • Multiple myeloma
  • Osteoma
  • Osteosarcoma

Thoracic wall trauma*

3.1.11 Abnormalities of the oesophagus

OESOPHAGEAL DILATATION

Generalised

Acquired megaoesophagus

• Idiopathic
• Immune-mediated neuromuscular disease
  • Myasthenia gravis
  • Polymyositis
  • Polyradiculoneuritis
  • Systemic lupus erythematosus
• Metabolic/endocrine
  • Hypoadrenocorticism (D)
  • Hypothyroidism* (D)
• Miscellaneous
  • Dysautonomia
  • Gastric dilatation/volvulus*
  • Hypertrophic muscular dystrophy
  • Oesophageal foreign body
  • Reflux oesophagitis
  • Thiamine deficiency
• Toxic
  • Botulinum toxin
  • Chlorinated hydrocarbons
  • Heavy metals
  • Herbicides
  • Organophosphates
  • Snake venom
  • Tetanus

Congenital megaoesophagus

• Canine giant axonal neuropathy (D)
• Glycogen storage disease
• Hereditary megaoesophagus
• Hereditary myopathy
• Vascular ring anomaly, e.g.
  • Double aortic arch
  • Normal aorta with aberrant right subclavian artery
  • Persistent right aortic arch
  • Persistent right ductus arteriosus
  • Right aortic arch with aberrant right subclavian artery

Transient megaoesophagus

• Hiatal hernia
• Respiratory infection
• Sedation/anaesthesia*

Localised

• Redundant oesophagus

Acquired

• Dilatation cranial to a gastro-oesophageal intussusception
• Dilatation cranial to acquired stricture, e.g.
  • Extraluminal compression
  • Granuloma
  • Mucosal adhesion
  • Neoplasia
  • Post general anaesthesia
• Dilatation cranial to an oesophageal foreign body*
• Oesophagitis
• Scar tissue post trauma

Congenital

• Dilatation cranial to a congenital stenosis
• Dilatation cranial to oesophageal hiatal hernia
• Segmental oesophageal hypomotility
• Vascular ring anomaly, e.g.
  • Double aortic arch
  • Normal aorta with aberrant right subclavian artery
  • Persistent right aortic arch
  • Persistent right ductus arteriosus
  • Right aortic arch with aberrant right subclavian artery
  • Oesophageal diverticulum

Transient

• Aerophagia*
• Dyspnoea*
• Swallowing*

INCREASED OESOPHAGEAL OPACITY

Bony density

• Foreign body*
• Megaoesophagus with collection of food
• Osteosarcoma, e.g.
  • Secondary to Spirocerca lupi (D)

Soft tissue density

• Megaoesophagus with collection of food/water
• Normal variation, e.g.
  • Fluid in the oesophagus*
  • Superimposition of the trachea*

Soft tissue mass

• Intraluminal
  • Food-containing oesophageal diverticulum
  • Foreign body*
  • Gastro-oesophageal intussusception
  • Oesophageal hiatal hernia
• Intramural
  • Abscess
  • Foreign body
  • Granuloma, e.g.
    • Spirocerca lupi (D)
  • Neoplasia
    • Metastatic
    • Primary oesophageal, e.g.
      • Leiomyoma/sarcoma
      • Squamous cell carcinoma
    • Secondary to Spirocerca lupi (D)
• Extraluminal
  • Abscess
  • Neoplasia
  • Paraoesophageal hiatal hernia

3.1.12 Abnormalities of the trachea

Dorsal displacement

• Artefact
  • Expiration
  • Rotation
  • Ventroflexion
• Breed variation*
• Cardiomegaly*
• Cranioventral mediastinal mass
• Heart base tumour
• Tracheobronchial lymphadenopathy*

Ventral displacement

• Craniodorsal mediastinal mass
• Megaoesophagus
• Oesophageal foreign body*
• Post-stenotic aortic dilatation
• Vertebral spondylosis

Lateral displacement

• Artefact
  • Expiration
  • Rotation
  • Ventroflexion
• Breed variation*
• Cranial mediastinal mass
• Heart base tumour
• Mediastinal shift q.v.
• Megaoesophagus
• Vascular ring anomaly

Narrowing

• Congenital hypoplasia

Artefact

• Hyperextension of the neck
• Superimposition of the muscle/oesophagus

External compression

• Cranial mediastinal mass
• Megaoesophagus
• Oesophageal foreign body*
• Vascular ring anomaly

Mucosal thickening

• Feline infectious peritonitis* (C)
• Inflammation, e.g.
  • Allergy*
  • Infection*
  • Irritant gases
• Submucosal haemorrhage, e.g.
  • Coagulopathy

Stricture/stenosis

• Congenital
• Excessive pressure from the cuff of endotracheal tube
• Focal intramural mass
• Post-traumatic injury

Tracheal collapse*

• Acquired, e.g.
  • Secondary to chronic bronchitis
• Congenital

Opacification of the lumen

• Abscess
• Aspiration of positive contrast agents
• Foreign body*
• Granuloma
• Oslerus osleri
• Polyp

Neoplasia

• Adenocarcinoma
• Chondrosarcoma
• Leiomyoma
• Lymphoma
• Mast cell tumour
• Osteochondroma
• Osteosarcoma

3.1.13 Pleural effusion

Bile pleuritis

• Ruptured biliary tree with diaphragmatic hernia

Blood

• Autoimmune disorders, e.g.
  • Immune-mediated thrombocytopenia
• Angiostrongylus vasorum infection
• Coagulopathy
• Neoplasia, e.g.
  • Haemangiosarcoma
• Trauma

Chyle

• Congenital duct malformation (D)
• Constrictive pleuritis
• Cranial mediastinal mass
• Diaphragmatic rupture*
• Feline dirofilariasis (C)
• Idiopathic*
• Lung lobe torsion
• Neoplasia
• Peritoneopericardial diaphragmatic hernia
• Post pacemaker implantation (C)
• Rupture of the thoracic duct

Heart disease*

• Dilated cardiomyopathy (C)
• Hypertrophic cardiomyopathy (C)*
• Pericardial disease
• Right-sided heart failure (C)

Obstruction of the thoracic duct

• Intraluminal
  • Granuloma
  • Neoplasia
• Extraluminal
  • Increased intrathoracic pressure

Exudate

• Actinomycosis
• Autoimmune disorders, e.g.
  • Rheumatoid arthritis
  • Systemic lupus erythematosus
• Feline infectious peritonitis* (C)
• Fungal infection
• Neoplasia*
• Nocardiosis
• Pneumonia*
• Pyothorax*
  • Extension from pulmonary parenchymal lesion
• Foreign body
  • Haematogenous spread
  • Penetrating thoracic wound
  • Penetration of the trachea/oesophagus
• Tuberculosis

Transudate/modified transudate

• Congestive heart failure*
• Diaphragmatic rupture*
• Foreign body
• Hyperthyroidism* (C)
• Hypoproteinaemia q.v.*
  • Liver disease*
  • Protein-losing enteropathy*
  • Protein-losing nephropathy*
• Idiopathic
• Lung lobe torsion
• Neoplasia, e.g.
  • Lymphoma*
• Pancreatitis
• Pneumonia*
• Thromboembolism

3.1.14 Pneumothorax

Artefact

• Overdevelopment
• Overexposure*
• Overinflation of the lungs
• Skin folds*
• Undercirculation

Iatrogenic

• Cardiopulmonary resuscitation
• Leaking chest drain
• Lung aspiration/biopsy
• Thoracocentesis
• Thoracotomy

Spontaneous

• Bacterial pneumonia
• Parasites
  • Dirofilariasis
  • Oslerus osleri
  • Paragonimus
• Pleural adhesions
• Rupture of congenital or acquired bullae, cysts or blebs
• Tumours*

Trauma

• Perforation of the lung*
• Perforation of the oesophagus
• Perforation of the thoracic wall*
• Perforation of the trachea/bronchi*

3.1.15 Abnormalities of the diaphragm

Cranial displacement

• Diaphragmatic rupture/hernia*

Abdominal causes

• Abdominal neoplasia*
• Ascites*
• Gastric dilatation*
• Obesity*
• Organomegaly*, e.g.
  • Liver
  • Spleen
• Pneumoperitoneum
• Pregnancy*
• Pyometra*

Thoracic causes

• Atelectasis
• Diaphragmatic paralysis
• Diaphragmatic tumour
• Expiratory film*
• Lung lobectomy
• Pleural adhesions
• Pulmonary fibrosis

Caudal displacement

Abdominal causes

• Abdominal body wall rupture/hernia leading to abdominal organ displacement
• Poor body condition

Thoracic causes

• Chronic dyspnoea*
• Deep inspiration*
• Intrathoracic mass*
• Pleural effusion*
• Pneumothorax*

Irregular diaphragmatic contour

• Diaphragmatic rupture/hernia*
• Hypertrophic muscular dystrophy
• Pleural masses, e.g.
  • Granuloma
  • Neoplasia
• Severe lung hyperinflation

Lack of visualisation of diaphragmatic border

• Artefact, e.g.
  • Expiratory film
• Diaphragmatic hernia*
• Increased lung density, e.g.
  • Alveolar pattern*
• Neoplasia adjacent to diaphragm*
• Peritoneopericardial diaphragmatic hernia
• Pleural effusion*

3.1.16 Mediastinal abnormalities

Mediastinal masses

• Aortic aneurysm
• Cyst
• Granuloma
  • Actinomycosis
  • Nocardiosis
• Haematoma
• Hiatal hernia
• Oesophageal dilatation
• Oesophageal foreign body*
• Oesophageal granuloma
  • Spirocerca lupi (D)
• Thymus

Artefact

• Left or right atrial enlargement
• Lung lobe tip
• Pleural fluid
• Post-stenotic dilatation of the aorta or pulmonary artery

Lymphadenopathy

• Bacterial
  • Actinomycosis
  • Nocardiosis
  • Tuberculosis
• Eosinophilic pulmonary granulomatosis
• Fungal
  • Blastomycosis
  • Coccidioidomycosis
  • Cryptococcosis
  • Histoplasmosis
• Neoplasia
  • Lymphoma*
  • Malignant histiocytosis
  • Metastatic neoplasia*

Neoplasia

• Ectopic parathyroid tumour
• Ectopic thyroid tumour
• Fibrosarcoma
• Heart base tumours
• Lipoma*
• Lymphoma*
• Malignant histiocytosis
• Rib tumour
• Thymoma

Mediastinal shift

Away from affected hemithorax

• Diaphragmatic rupture/hernia*
• Lobar emphysema
• Lung mass*
• Oblique view
• Pleural mass*
• Unilateral pleural effusion*
• Unilateral pneumothorax*

Towards affected hemithorax

• Atelectasis
  • Feline asthma* (C)
  • Foreign body*
  • Mass*
  • Radiation
• Hypostatic congestion*, e.g.
  • General anaesthesia
  • Illness resulting in prolonged lateral recumbency
• Lobar agenesis/hypoplasia
• Lobectomy
• Lung lobe torsion
• Oblique view
• Radiation-induced fibrosis
• Unilateral phrenic nerve paralysis

Pneumomediastinum

• Emphysematous mediastinitis
• Iatrogenic
• Secondary to severe dyspnoea*

Air from neck

• Gas-forming bacteria
• Trauma*, e.g.
  • Jugular venepuncture
  • Oesophagus
  • Pharynx
  • Soft tissue
  • Trachea

Air from bronchi/lungs, e.g.

• Lung lobe torsion
• Spontaneous
• Trauma*

Widened mediastinum

• Normal variation*
  • Bulldogs
• Abscess
  • Foreign body
• Masses (see succeeding text)
• Megaoesophagus q.v.
• Obesity*

Mediastinal effusions, e.g.

• Chylomediastinum
• Haemorrhage
  • Coagulopathy
  • Neoplasia
  • Trauma*

Mediastinitis/mediastinal abscess

• Feline infectious peritonitis (C)
• Lymphadenitis
• Oesophageal/tracheal perforation
• Penetrating neck wound*
• Pleuritis*
• Pneumonia*

Oedema*

• Congestive heart failure*
• Hypoproteinaemia* q.v.
• Neoplasia*
• Trauma*

3.2 Abdominal radiography

3.2.1 Liver

Focal enlargement

Infection/inflammation

• Abscess
• Granuloma

Miscellaneous

• Biliary pseudocyst
• Cyst
• Haematoma
• Hepatic arteriovenous fistula
• Hyperplastic/regenerative nodule*
• Liver lobe torsion

Neoplasia*

• Biliary cystadenoma
• Haemangiosarcoma
• Hepatocellular carcinoma*
• Hepatoma
• Lymphoma*
• Malignant histiocytosis
• Metastatic*

Generalised enlargement

Endocrine disease

• Acromegaly
• Diabetes mellitus*
• Hyperadrenocorticism

Infection/inflammation

• Abscess
• Feline infectious peritonitis* (C)
• Fungal infection
• Granuloma
• Hepatitis*
• Lymphocytic cholangitis*

Neoplasia, e.g.

• Haemangiosarcoma
• Lymphoma*
• Malignant histiocytosis
• Mast cell infiltration (mastocytosis/mast cell tumour)
• Metastatic tumours*

Venous congestion

• Caudal vena cava occlusion (post caval syndrome)
  • Adhesions
  • Cardiac neoplasia
  • Congenital cardiac disease
  • Diaphragmatic rupture/hernia*
  • Dirofilariasis
  • Pericardial disease
  • Thoracic mass
  • Thrombosis
  • Trauma*
• Right-sided congestive heart failure, e.g.
  • Dilated cardiomyopathy*
  • Pericardial disease, e.g. pericardial effusion q.v.
  • Tricuspid regurgitation

Miscellaneous

• Amyloidosis
• Cholestasis q.v.*
• Cirrhosis (early)*
• Hepatic lipidosis (C)
• Nodular hyperplasia*
• Storage diseases

Drugs

• Glucocorticoids

Reduced liver size

• Breed variation (e.g. apparent microhepatica in deep-chested dogs)
• Cirrhosis
• Diaphragmatic rupture/hernia*
• Hypoadrenocorticism (D)
• Idiopathic hepatic fibrosis
• Portosystemic shunt
  • Acquired
  • Congenital

3.2.2 Spleen

Enlargement

Normal, e.g.

• Breed related*

Congestion

• Gastric dilatation/volvulus*
• Portal hypertension
• Right-sided congestive heart failure
• Sedation and general anaesthesia*
• Splenic thrombosis
• Splenic torsion

Haematoma*

• Idiopathic
• Secondary to neoplasia
• Trauma

Hyperplasia*

• Chronic anaemia q.v.
• Chronic infection
• Lymphoid

Inflammation/immune mediated

• Hypereosinophilic syndrome
• Immune-mediated haemolytic anaemia
• Systemic lupus erythematosus

Infection

• Abscess
• Babesiosis
• Bacteraemia
• Ehrlichiosis
• Feline infectious peritonitis* (C)
• Fungal infections
• Infectious canine hepatitis (D)
• Leishmaniasis
• Mycobacteria
• Mycoplasma
• Toxoplasmosis
• Salmonellosis
• Septicaemia*

Neoplasia

• Fibrosarcoma
• Haemangioma
• Haemangiosarcoma*
• Leiomyosarcoma
• Leukaemia
• Lymphoma*
• Malignant histiocytosis
• Multiple myeloma
• Systemic mastocytosis

Miscellaneous

• Amyloidosis
• Extramedullary haematopoiesis*
• Infarction
• Splenic myeloid metaplasia

Trauma

• Foreign body
• Penetrating wound

Reduction in size

• Dehydration*
• Shock* q.v.

Absence

• Artefact
• Displacement through hernia/rupture
• Splenectomy

3.2.3 Stomach

Abnormal contents

Gas

• Aerophagia*
• Gastric dilatation/volvulus*

Mineral opacity

• Foreign body*
• Gravel sign (outflow obstruction)*
• Iatrogenic
  • Barium
  • Bismuth
  • Kaolin

Soft tissue opacity

• Blood clot
• Food/ingested liquid*
• Foreign body*
• Intussusception
• Neoplasia
• Polyp

Caudal displacement

• Enlargement of the thoracic cavity, e.g.
  • Overinflation of the lungs
  • Pleural effusion* q.v.
• Hepatomegaly* q.v.

Cranial displacement

• Diaphragmatic hernia/rupture*
• Hiatal hernia
• Late pregnancy*
• Microhepatica
• Neoplasia/mass, e.g.
  • Colonic
  • Mesenteric
  • Pancreatic
• Peritoneopericardial diaphragmatic hernia

Delayed gastric emptying

• Gastritis*
• General anaesthesia/sedation*

Functional disorders

• Adynamic ileus*
• Dysautonomia
• Pancreatitis*
• Primary dysmotilities
• Uraemia* q.v.

Pyloric outflow obstruction

• Chronic hyperplastic gastropathy
• Fibrosis/scar tissue
• Foreign body*
• Granuloma
• Neoplasia
  • Biliary
  • Duodenal
  • Gastric
  • Pancreatic
• Pyloric hypertrophy
  • Mucosal
  • Muscular
• Ulceration

Pylorospasm

• Anxiety
• Stress

Ulceration

• Duodenal
• Gastric

Distended

• Acute gastritis*
• Gastric dilatation volvulus*
• Pancreatitis*

Aerophagia*

• Bolting food
• Dyspnoea
• Pain

Iatrogenic

• Anticholinergic drugs
• Endoscopic inflation
• Misplaced endotracheal tube
• Stomach tube

Outflow obstruction

• Fibrosis/scarring
• Foreign body*
• Granuloma
• Muscular or mucosal hypertrophy
• Neoplasia
• Pylorospasm
• Ulceration

Increased wall thickness (contrast radiography)

Diffuse

• Inflammation
  • Chronic gastritis*
  • Eosinophilic gastritis*
• Neoplasia
  • Lymphoma
  • Pancreatic tumour
• Chronic hyperplastic gastropathy

Focal

• Artefact
  • Empty stomach
• Hypertrophy
  • Mucosal
  • Muscular
• Inflammation
  • Eosinophilic
  • Fungal infection
  • Granulomatous
• Neoplasia
  • Adenocarcinoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma

3.2.4 Intestines

SMALL INTESTINE

Bunching

• Adhesions*
• Linear foreign body*
• Obesity*

Displacement

Caudal displacement

• Distended stomach*
• Empty urinary bladder*
• Hepatomegaly* q.v.
• Hernias*
  • Inguinal*
  • Perineal*

Cranial displacement

• Empty stomach*
• Enlarged urinary bladder* q.v.
• Enlarged uterus*
  • Pregnancy*
  • Pyometra*
• Microhepatica

Diaphragmatic disorders

• Peritoneopericardial diaphragmatic hernia
• Rupture/hernia*

Lateral displacement

• Hepatomegaly* q.v.
• Prolonged lateral recumbency*
• Renomegaly* q.v.
• Splenomegaly* q.v.

Increased width of small intestinal loops

Artefact

• Mistaking colon for small intestine

Functional obstruction

• Dysautonomia
• Electrolyte imbalances* q.v.
• Pancreatitis*
• Peritonitis*
• Recent abdominal surgery*
• Secondary to chronic mechanical obstruction*
• Severe gastroenteritis*

Mechanical obstruction

• Abscess
• Adhesions*
• Caecal impaction
• Constipation*
• Foreign body*
• Granuloma
• Intestinal volvulus
• Intussusception
• Neoplasia, e.g.
  • Adenocarcinoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma
• Polyps
• Strangulation in hernia/mesenteric tear
• Stricture

Variation in small intestinal contents

Bony/mineral density

• Food*
• Foreign body*
• Iatrogenic
  • Contrast media
  • Medications

Fluid/soft tissue density

• Normal*
• Diffuse infiltrative neoplasia
• Functional obstruction
  • Dysautonomia
  • Electrolyte imbalances* q.v.
  • Pancreatitis*
  • Peritonitis*
  • Recent abdominal surgery*
  • Secondary to chronic mechanical obstruction*
  • Severe gastroenteritis*
• Mechanical obstruction
  • Abscess
  • Adhesions*
  • Caecal impaction
  • Constipation*
  • Foreign body*
  • Granuloma
  • Intestinal volvulus
  • Intussusception
  • Neoplasia, e.g.
    • Adenocarcinoma
    • Leiomyoma
    • Leiomyosarcoma
    • Lymphoma
  • Polyps
  • Strangulation in hernia/mesenteric tear
• Mistaking colon or enlarged uterus for small intestine

Gas density

• Normal*
• Adhesions*
• Aerophagia*
• Enteritis*
• Functional obstruction
  • Dysautonomia
  • Electrolyte imbalances* q.v.
  • Pancreatitis*
  • Peritonitis*
  • Recent abdominal surgery*
  • Secondary to chronic mechanical obstruction*
  • Severe gastroenteritis*
• Mechanical obstruction
  • Abscess
  • Adhesions
  • Caecal impaction
  • Constipation*
  • Foreign body*
  • Granuloma
  • Intestinal volvulus
  • Intussusception
  • Neoplasia, e.g.
    • Adenocarcinoma
    • Leiomyoma
    • Leiomyosarcoma
    • Lymphoma
  • Polyps
  • Strangulation in hernia/mesenteric tear
• Partial obstruction*
• Prolonged recumbency*

Delayed intestinal transit time

• Diffuse neoplasia
• Enteritis*
• Inflammatory bowel disease*
• Sedation/general anaesthesia*

Functional obstruction

• Dysautonomia
• Electrolyte imbalances* q.v.
• Pancreatitis*
• Peritonitis*
• Recent abdominal surgery*
• Secondary to chronic mechanical obstruction*
• Severe gastroenteritis*

Mechanical obstruction (partial)

• Abscess
• Adhesions*
• Caecal impaction
• Constipation*
• Foreign body*
• Granuloma
• Intussusception
• Neoplasia, e.g.
  • Adenocarcinoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma
• Polyps
• Strangulation in hernia/mesenteric tear

Luminal filling defects on contrast radiography

• Foreign body*
• Intussusception
• Neoplasia
• Parasitism*
• Polyp
• Ulcer

Increased wall thickness (contrast radiography)

• Inflammatory bowel disease*
• Fungal infections
• Lymphangiectasia
• Neoplasia, e.g.
  • Adenocarcinoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma

LARGE INTESTINE

Dilatation

• Constipation/obstipation* q.v.

Displacement

Ascending colon

• Adrenal mass
• Duodenal dilatation*
• Hepatomegaly* q.v.
• Lymphadenopathy* q.v.
• Pancreatic mass
• Renomegaly q.v.

Transverse colon

• Diaphragmatic rupture/hernia*
• Dilatation of the stomach*
• Enlarged bladder* q.v.
• Enlarged uterus*
• Hepatomegaly* q.v.
• Lymphadenopathy* q.v.
• Microhepatica q.v.
• Mid-abdominal mass*
• Pancreatic mass

Descending colon

• Adrenal mass
• Enlarged bladder* q.v.
• Enlarged uterus* q.v.
• Hepatomegaly* q.v.
• Lymphadenopathy* q.v.
• Prostatomegaly*
• Renomegaly* q.v.
• Retroperitoneal fluid
• Splenomegaly* q.v.

Rectum

• Paraprostatic cyst
• Perineal hernia*
• Prostatomegaly*
• Sacral or vertebral mass
• Urethral mass
• Vaginal mass
• Other pelvic/intrapelvic mass

Variation in contents

Empty

• Normal
• Caecal inversion
• Enema
• Gastric/small intestinal obstruction* q.v.
• Large intestinal diarrhoea* q.v.
• Intussusception
• Neoplasia
• Typhlitis

Soft tissue/mineral density

• Caecal impaction
• Constipation/obstipation* q.v.
• Undigested dietary material*

Increased wall thickness (contrast radiography)

• Colitis*
• Fibrosis from previous trauma/surgery
• Neoplasia

Luminal filling defects on contrast radiography

• Caecal inversion
• Faeces*
• Foreign body*
• Intussusception
• Masses
  • Neoplasia
  • Polyps

3.2.5 Ureters

Dilated

• Ascending infection
• Ectopic ureter
  • Congenital
  • Ureteral obstruction, e.g. ligation
• External compression, e.g.
  • Abdominal mass*
• Hydroureter
  • Iatrogenic
  • Neoplasia
  • Stricture following ureterolith or other trauma
  • Ureterolith

Ureteral diverticula

• Ureterocoele

3.2.6 Bladder

Abnormal bladder contents (contrast cystography)

Filling defects

• Artefact
• Air bubbles*
• Blood clots*
• Calculi*
• Neoplasia
• Polyps
• Severe cystitis*

Increased opacity

• Blood clots*
• Neoplasia
• Polyps
• Uroliths*

Abnormal shape

• Diverticula
• Herniation
• Neoplasia
• Patent urachus
• Positioning errors
• Rupture

Displacement

• Abdominal hernia/rupture*
• Constipation/obstipation* q.v.
• Enlarged uterus* q.v.
• Lymphadenopathy* q.v.
• Obesity*
• Perineal hernia*
• Prepubic tendon rupture
• Prostatomegaly*
• Short urethra
• Traumatic urethral injury

Failure of the bladder to distend (contrast radiography)

• Congenital defects, e.g.
  • Ectopic ureters
  • Hypoplasia
• Cystitis*
• Neoplasia
• Rupture

Enlarged bladder

• Normal*

Functional obstruction

• Neurological
  • Cauda equina syndrome
  • Dysautonomia
  • Upper motor neurone spinal cord lesion q.v., e.g.
    • Intervertebral disc disease* (D)
    • Trauma
    • Tumour
• Psychogenic*
  • Lack of outside/litter access
  • Pain
  • Stress

Mechanical obstruction

• Crystalline–matrix plugs*
• Neoplasia
  • Bladder
  • Urethra
• Prostatomegaly*
• Urethral stricture
• Uroliths*
  • Bladder neck
  • Urethra

Small bladder

• Anuria
• Congenital hypoplasia
• Ectopic ureters
• Feline lower urinary tract disease
• Non-distensible bladder
  • Diffuse bladder wall neoplasia
  • Severe cystitis, e.g.
    • Calculi*
    • Infection*
    • Trauma*
• Recent voiding*
• Ruptured bladder
• Ruptured ureters

Decreased opacity

• Emphysematous cystitis
• Iatrogenic

Increased opacity

• Chronic cystitis*
• Foreign body
• Neoplasia
• Radiopaque calculi*
  • Oxalate
  • Silica
  • Struvite
• Superimposition of other organs

Thickening of the bladder wall (contrast cystography)

• Chronic cystitis*
• Chronic outflow obstruction
• Polyps
• Small bladder*

Neoplasia

• Adenocarcinoma
• Leiomyoma
• Leiomyosarcoma
• Metastatic neoplasia
• Rhabdomyosarcoma
• Squamous cell carcinoma
• Transitional cell carcinoma

Non-visualisation

• Ascites
• Bladder hypoplasia
• Bladder rupture
• Empty bladder
  • Bilateral ectopic ureters
  • Cystitis*
  • Post voiding*
• Lack of abdominal fat
• Positioning fault

3.2.7 Urethra

Contrast medium leakage

• Hypospadia
• Normal
• Previous urethrotomy/urethrostomy
• Prostatic disease*
• Urethral rupture
  • Iatrogenic
  • Trauma

Displacement

• Adjacent neoplasia
• Bladder displacement
• Prostatic disease*

Filling defects (contrast urethrography)

• Air bubbles*
• Blood clots
• Neoplasia
• Uroliths*

Strictures/irregular surface

• Neoplasia
• Previous surgery
• Previous uroliths
• Prostatic disease*
• Urethritis*

3.2.8 Kidneys

Dilatation of the renal pelvis (contrast radiography)

• Chronic pyelonephritis
• Diuresis
• Ectopic ureter
• Nephrolithiasis or ureterolithiasis
• Renal neoplasia

Hydronephrosis

• Extrinsic mass
• Neoplasia
  • Bladder
  • Prostate
  • Trigone
• Paraureteral pseudocyst
• Ureteral blood clot
• Ureteral inflammation
• Ureteral stricture
• Ureterolith

Renal pelvic blood clot

• Coagulopathy
• Iatrogenic (post biopsy)
• Idiopathic renal haemorrhage
• Neoplasia
• Trauma

Enlargement

Irregular outline

• Abscess
• Cyst
• Granuloma
• Haematoma
• Infarction
• Neoplasia
  • Adenoma
  • Anaplastic sarcoma
  • Cystadenocarcinoma
  • Haemangioma/haemangiosarcoma
  • Metastatic neoplasia
  • Nephroblastoma
  • Papilloma
  • Renal cell carcinoma
  • Transitional cell carcinoma
• Polycystic kidney disease

Smooth outline

• Acute pyelonephritis
• Acute kidney injury q.v.
• Amyloidosis
• Compensatory renal hypertrophy
• Congenital conditions
  • Ectopic ureter
  • Ureterocoele
• Feline infectious peritonitis* (C)
• Hydronephrosis
  • Extrinsic mass
  • Neoplasia, e.g.
    • Bladder
    • Prostate
    • Trigone
  • Paraureteral pseudocyst
  • Ureteral blood clot
  • Ureteral inflammation
  • Ureterolith
  • Ureteral stricture
• Neoplasia, e.g.
  • Lymphoma*
• Nephritis*
• Perirenal pseudocysts
• Portosystemic shunts
• Subcapsular abscess
• Subcapsular haematoma

Increased radiopacity

• Nephroliths

Artefact

• Superimposition

Dystrophic mineralisation

• Abscess
• Granuloma
• Haematoma
• Neoplasia
• Osseous metaplasia

Nephrocalcinosis

• Chronic kidney disease* q.v.
• Ethylene glycol toxicity
• Hyperadrenocorticism
• Hypercalcaemia q.v.
• Nephrotoxic drugs
• Renal telangiectasia

Non-visualisation

• Artefact/technical factors
• Nephrectomy
• Obscured by gastrointestinal tract contents*
• Reduced intra-abdominal contrast* q.v.
• Retroperitoneal effusion
  • Haemorrhage
  • Urine
• Unilateral renal agenesis
• Very small kidneys

Small kidneys

• Chronic glomerulonephritis
• Chronic interstitial nephritis*
• Chronic pyelonephritis

3.2.9 Loss of intra-abdominal contrast

Artefact

• Ultrasound gel on coat*
• Wet hair coat*

Ascites/peritoneal fluid

Bile

• Ruptured biliary tract
  • Cholelithiasis
  • Neoplasia
  • Post surgery, e.g.
    • Cholecystectomy
  • Severe cholecystitis
  • Trauma

Blood

• Angiostrongylus vasorum
• Coagulopathy q.v.
• Neoplasia*, e.g.
  • Haemangiosarcoma
• Trauma

Chyle

• Lymphangiectasia
• Ruptured cisterna chyli
  • Neoplasia
  • Trauma

Exudate

• Feline infectious peritonitis* (C)
• Septic peritonitis, e.g.
  • Iatrogenic/nosocomial
  • Neoplasia*
  • Pancreatitis*
  • Penetrating wound
  • Ruptured viscus
    • Neoplasia*
    • Post surgery, e.g.
    • Enterotomy wound dehiscence*
    • Trauma*

Transudate/modified transudate, e.g.

• Cardiac tamponade
• Caudal vena caval obstruction
• Hepatic disease
  • Cholangiohepatitis*
  • Chronic hepatitis*
  • Cirrhosis*
  • Fibrosis*
• Hypoalbuminaemia* q.v.
• Neoplasia
• Portal hypertension
• Right-sided heart failure*

Urine

• Lower urinary tract rupture
  • Bladder
  • Ureter
  • Urethra

Diffuse peritoneal neoplasia

Lack of abdominal fat

• Emaciation*
• Immaturity*

Peritonitis

Irritant

• Bile
• Urine

Miscellaneous

• Neoplasia
• Pancreatitis*

Septic

• Bile leakage
• Gastrointestinal tract leakage
  • Devitalisation
    • Foreign body*
    • Gastric dilatation/volvulus*
    • Intestinal volvulus
    • Intussusception
  • Perforation
    • Enterotomy wound dehiscence*
    • Gastroduodenal ulceration
    • Penetrating wound
• Hepatic abscess
• Ruptured prostatic abscess
• Ruptured uterus
• Septicaemia*
• Splenic abscesses
• Urinary tract disruption

Viral

• Feline infectious peritonitis* (C)

3.2.10 Prostate

Displacement

• Abdominal weakness
• Full bladder*
• Perineal hernia*
• Prostatomegaly*

Enlargement

• Benign prostatic hyperplasia*
• Paraprostatic cysts
• Prostatic cysts
• Prostatic neoplasia
• Prostatitis*
• Testicular neoplasia*

3.2.11 Uterus

Enlargement

• Haemometra
• Hydrometra
• Mucometra
• Neoplasia
• Post partum*
• Pregnancy*
• Pyometra*
• Torsion

3.2.12 Abdominal masses

Cranial abdomen

• Adrenal mass
• Hepatomegaly/hepatic mass* q.v.
• Pancreatic mass
• Stomach distension/mass*

Mid abdomen

• Cryptorchidism*
• Mesenteric lymphadenopathy*
• Ovarian masses*
• Pancreatic enlargement
• Renomegaly/renal mass* q.v.
• Small intestine
  • Foreign body*
  • Neoplasia*
  • Obstruction*
• Splenomegaly/splenic mass* q.v.

Caudal abdomen

• Distended urinary bladder* q.v.
• Enlarged uterus* q.v.
• Large intestine
  • Foreign body*
  • Neoplasia
  • Obstruction*
• Lymphadenopathy
• Prostatomegaly*

3.2.13 Abdominal calcification/mineral density

Abdominal fat

• Idiopathic
• Pansteatitis

Adrenal glands

• Idiopathic
• Neoplasia

Arteries

• Arteriosclerosis

Gastrointestinal tract

• Foreign bodies and ingesta*
• Iatrogenic
  • Contrast media
  • Medication
• Uraemic gastritis* q.v.

Genital tract

• Chronic prostatitis*
• Cryptorchidism*
• Neoplasia
• Ovarian neoplasia
• Ovarian or prostatic cyst*
• Pregnancy*

Liver

• Abscess
• Cholelithiasis
• Chronic cholecystitis*
• Chronic hepatopathy*
• Cyst
• Granuloma
• Haematoma
• Neoplasia
• Nodular hyperplasia*

Lymph nodes

• Inflammation*
• Neoplasia*

Miscellaneous

• Calcinosis cutis
• Chronic hygroma
• Foreign body*
• Mammary gland neoplasia*
• Myositis ossificans

Pancreas

• Chronic pancreatitis*
• Fat necrosis
• Neoplasia
• Pancreatic pseudocyst

Spleen

• Abscess
• Haematoma*
• Histoplasmosis

Urinary tract

• Chronic inflammation*
• Neoplasia
• Nephrocalcinosis
  • Chronic kidney disease* q.v.
  • Hyperadrenocorticism
  • Hypercalcaemia* q.v.
  • Nephrotoxic drugs q.v.
• Urolithiasis*

3.3 Skeletal radiography

3.3.1 Fractures

Congenital/inherited weakness, e.g.

• Incomplete ossification of the humeral condyle

Iatrogenic

• Bone biopsy
• Complication of orthopaedic surgery

Pathological

• Bone cyst
• Osteopenia q.v.

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Metastatic neoplasia
• Multilobular osteochondrosarcoma
• Multiple myeloma
• Osteosarcoma*

Osteomyelitis

• Bacterial*
• Fungal
• Protozoal, e.g.
  • Leishmaniasis

Traumatic*

3.3.2 Altered shape of the long bones

Abnormally straight

• Premature closure of growth plate

Angulation

• Fractures*

Bowing

• Asymmetric growth plate bridging
• Iatrogenic, e.g.
• Plating
• Metaphyseal osteopathy
• Chondrodysplasia
• Chondrodystrophy
  • May be normal breed variation*
• Congenital hypothyroidism
• Rickets
• Tension
  • Quadriceps contracture
  • Shortening of the ulna

Irregular margination

• Calcifying tendinopathy
• Bone cyst
  • Enchondromatosis
• Metaphyseal osteopathy
• Neoplasia
  • Chondrosarcoma
  • Multiple cartilaginous exostoses
  • Osteosarcoma*
• Periosteal remodelling q.v.

3.3.3 Dwarfism

Disproportionate

• Chondrodysplasia
• Hypervitaminosis A
• Hypothyroidism
• Mucolipidosis type II
• Mucopolysaccharidosis
• Rickets

Proportionate

• Hypothyroidism
• Pituitary dwarfism

3.3.4 Delayed ossification/growth plate closure

• Chondrodysplasia
• Copper deficiency
• Early neutering
• Hypervitaminosis D
• Hypothyroidism (D)
• Mucopolysaccharidosis
• Pituitary dwarfism

3.3.5 Increased radiopacity

• Artefact
• Bone infarcts
• Folding fractures*
• Growth arrest lines
• Lead poisoning
• Metaphyseal osteopathy
• Neoplasia
• Panosteitis
• Skeletal immaturity* (metaphyseal condensation)

Osteomyelitis

• Bacterial*
• Fungal
• Protozoal, e.g.
  • Leishmaniasis

Osteopetrosis

• Acquired
  • Chronic excess dietary intake of calcium
  • Chronic hypervitaminosis D
  • Feline leukaemia virus* (C)
  • Idiopathic
  • Myelofibrosis
• Congenital

3.3.6 Periosteal reactions

• Craniomandibular osteopathy
• Hip dysplasia*
• Hypertrophic osteopathy
• Hypervitaminosis A
• Metaphyseal osteopathy
• Mucopolysaccharidosis
• Neoplasia
• Panosteitis
• Trauma*

Infection

• Bacterial*
• Fungal
• Protozoal
  • Hepatozoonosis
  • Leishmaniasis
• Tuberculosis

3.3.7 Bony masses

Neoplasia

Benign

• Chondroma
• Endochondroma
• Monostotic osteochondroma
• Multiple osteochondroma (C)
• Osteoma
• Polyostotic osteochondroma/multiple cartilaginous exostoses

Malignant

• Locally invasive soft tissue
  • Malignant melanoma of the digit
  • Soft tissue sarcomas
  • Squamous cell carcinoma of the digit
• Primary bone
  • Chondrosarcoma
  • Fibrosarcoma
  • Giant cell tumour
  • Haemangiosarcoma
  • Liposarcoma
  • Lymphoma
  • Multiple myeloma
  • Multilobular osteochondrosarcoma
  • Osteosarcoma
  • Parosteal osteosarcoma
  • Plasma cell tumour
  • Undifferentiated sarcoma
• Tumours which metastasise to bone
  • Mammary carcinoma
  • Prostatic carcinoma
  • Pulmonary carcinoma
  • Sarcomas of the rib/chest wall

Miscellaneous

• Craniomandibular osteopathy
• Enthesopathies

Proliferative joint disease

• Disseminated skeletal hyperostosis
• Feline periosteal proliferative polyarthropathy (C)
• Hypervitaminosis A
• Osteoarthritis*

Trauma

• Callus*
• Hypertrophic non-union
• Periosteal reaction

3.3.8 Osteopenia

Artefact

Disuse

• Fracture*
• Lameness*
• Paralysis

Iatrogenic

• Chronic anticonvulsant therapy, e.g.
  • Phenobarbitone
  • Phenytoin
  • Primidone
• Chronic glucocorticoid administration
• Stress protection from plating/casting

Metabolic/endocrine/systemic

• Diabetes mellitus*
• Hyperadrenocorticism
• Hyperthyroidism* (C)
• Lactation*
• Mucopolysaccharidosis
• Pregnancy*
• Primary hyperparathyroidism
• Renal secondary hyperparathyroidism*

Miscellaneous

• Ageing changes
• Osteogenesis imperfecta
• Panosteitis

Neoplasia

• Multiple myeloma
• Pseudohyperparathyroidism (see succeeding text)

Nutrition

• Chronic protein malnutrition
• Hypervitaminosis A
• Hyper-/hypovitaminosis D
• Nutritional secondary hyperparathyroidism
• Pseudohyperparathyroidism
  • Adenocarcinoma of the apocrine glands of anal sacs
  • Gastric squamous cell carcinoma
  • Lymphoma*
  • Mammary adenocarcinoma
  • Multiple myeloma
  • Testicular interstitial cell tumour
  • Thyroid adenocarcinoma
• Rickets

Toxins

• Lead poisoning

3.3.9 Osteolysis

• Avascular necrosis of the femoral head* (D)
• Bone cysts
• Feline femoral metaphyseal osteopathy (C)
• Fibro-osseous dysplasia
• Fibrous dysplasia
• Infarct
• Intraosseous epidermoid cysts
• Metaphyseal osteopathy
• Pressure atrophy
• Retained cartilaginous core
• Trauma*

Infection

• Bacterial
  • Bone abscess
  • Iatrogenic, e.g. around surgical implants*
  • Osteomyelitis*
  • Sequestrum
• Fungal
• Protozoal
  • Leishmaniasis

Neoplasia

• Enchondroma
• Malignant soft tissue tumour
• Metastatic tumour
• Multiple myeloma
• Osteochondroma/multiple cartilaginous exostoses
• Osteoclastoma

3.3.10 Mixed osteolytic/osteogenic lesions

Infection

Bacterial

• Osteomyelitis*
• Sequestrum

Fungal

• Aspergillosis
• Blastomycosis
• Coccidioidomycosis
• Cryptococcosis
• Histoplasmosis

Protozoal

• Leishmaniasis

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Liposarcoma
• Malignant soft tissue tumour*
• Metastatic*
• Osteosarcoma*

3.3.11 Joint changes

Joint space – increased size

• Degenerative joint disease
• Intra-articular soft tissue mass
• Joint effusion*
• Juvenile animal
• Positioning artefact/traction
• Subluxation

Epiphyseal dysplasia

• Chondrodysplasia
• Congenital hypothyroidism
• Mucopolysaccharidosis
• Pituitary dwarfism

Subchondral osteolysis

• Neoplasia
• Osteochondrosis
• Rheumatoid arthritis
• Septic arthritis*

Joint space – reduced size

• Degenerative joint disease*
• Erosive rheumatoid arthritis
• Erosive septic arthritis
• Periarticular fibrosis
• Positioning artefact*

Mixed osteolytic/proliferative joint disease

• Avascular necrosis of the femoral head* (D)
• Feline periosteal proliferative polyarthropathy (C)
• Feline tuberculosis (C)
• Leishmaniasis
• Neoplasia
• Non-infectious erosive polyarthritis
• Osteochondromatosis
• Periosteal proliferative polyarthritis
• Repeated haemarthroses
• Rheumatoid arthritis
• Septic arthritis*
• Villonodular synovitis

Osteolytic joint disease

• Avascular necrosis of the femoral head* (D)
• Chronic haemarthrosis
• Epiphyseal dysplasia causing apparent osteolysis
• Incomplete ossification in juveniles
• Osteochondrosis
• Osteopenia q.v.
• Rheumatoid arthritis
• Subchondral cysts
• Villous nodular synovitis

Infection

• Feline tuberculosis (C)
• Leishmaniasis
• Mycoplasmosis
• Septic arthritis*

Neoplasia

• Metastatic digital carcinoma
• Synovial sarcoma
• Other soft tissue neoplasia

Proliferative joint disease

• Disseminated idiopathic skeletal hyperostosis
• Enthesopathies
• Hypervitaminosis A
• Mucopolysaccharidosis
• Systemic lupus erythematosus

Neoplasia

• Osteoma
• Osteosarcoma*
• Synovial osteochondroma

Osteoarthritis

• Ageing*
• Angular limb deformities
• Chondrodysplasia
• Elbow dysplasia*
• Hip dysplasia*
• Post articular fractures*
• Post surgery*
• Other chronic joint stresses
• Repeated haemarthroses
• Soft tissue damage, e.g.
  • Ruptured cranial cruciate ligament*

Soft tissue swelling – joint effusion

• Haemarthrosis
• Ligament injury
• Osteoarthrosis
• Osteochondrosis
• Shar Pei fever (D)
• Soft tissue callus
• Synovial cyst
• Trauma*
• Villonodular synovitis

Arthritis

• Iatrogenic
  • Drugs, e.g.
    • Sulphonamides
  • Vaccine reactions
• Idiopathic polyarthritis
• Immune-mediated disease
  • Arthritis of the Akita (D)
  • Gastrointestinal disease associated
  • Idiopathic
  • Neoplasia associated
  • Polyarteritis nodosa
  • Polyarthritis/meningitis
  • Polyarthritis/polymyositis
  • Systemic lupus erythematosus
  • Vaccine reaction
• Infection
  • Borreliosis
  • Ehrlichiosis
  • Sepsis (bacterial)*

Periarticular swelling

• Abscess*
• Cellulitis*
• Haematoma
• Neoplasia
• Oedema*

3.4 Radiography of the head and neck

3.4.1 Increased radiopacity/bony proliferation of the maxilla

• Acromegaly
• Healing/healed fracture*
• Neoplasia
• Osteomyelitis*

3.4.2 Decreased radiopacity of the maxilla

• Granuloma
• Nasolacrimal duct cysts

Hyperparathyroidism

• Nutritional secondary
• Primary
• Renal secondary*

Neoplasia

• Fibrosarcoma
• Local extension of tumour, e.g.
  • From nasal cavity*
• Malignant melanoma
• Osteosarcoma*
• Squamous cell carcinoma

Odontogenic cysts

• Adamantinoma
• Ameloblastoma
• Complex odontoma
• Dentigerous cyst

Periodontal disease*

3.4.3 Increased radiopacity/bony proliferation of the mandible

• Acromegaly
• Canine leukocyte adhesion deficiency (D)
• Craniomandibular osteopathy
• Healing/healed fracture*
• Neoplasia
• Osteomyelitis*

3.4.4 Decreased radiopacity of the mandible

• Granuloma
• Periodontal disease

Hyperparathyroidism

• Nutritional secondary
• Primary
• Renal secondary*

Neoplasia

• Fibrosarcoma
• Malignant melanoma
• Osteosarcoma*
• Squamous cell carcinoma

Odontogenic cysts

• Adamantinoma
• Ameloblastoma
• Complex odontoma
• Dentigerous cyst

3.4.5 Increased radiopacity of the tympanic bulla

Abnormal contents

• Cholesteatoma
• Granuloma
• Neoplasia
• Otitis media*
• Polyp*

Artefact

• Positioning

Thickening of the bulla wall

• Canine leukocyte adhesion deficiency (D)
• Craniomandibular osteopathy
• Neoplasia
• Otitis media*
• Polyp*

3.4.6 Decreased radiopacity of the nasal cavity

Artefact

Turbinate destruction

• Aspergillosis
• Congenital defect of the hard palate
• Chronic rhinitis, e.g. viral
• Destruction of the palatine or maxillary bone, e.g.
  • Neoplasia*
• Foreign body*
• Previous rhinotomy

3.4.7 Increased radiopacity of the nasal cavity

Artefact

Epistaxis q.v.

Miscellaneous

• Foreign body
• Hyperparathyroidism
• Kartagener's syndrome
• Polyp
• Primary ciliary dyskinesia

Neoplasia

Nasal cavity*

• Adenocarcinoma*
• Chondrosarcoma
• Esthesioneuroblastoma
• Fibrosarcoma
• Haemangiosarcoma
• Histiocytoma
• Leiomyosarcoma
• Liposarcoma
• Lymphoma*
• Malignant fibrous histiocytoma
• Malignant melanoma
• Malignant nerve sheath tumour
• Mast cell tumour
• Myxosarcoma
• Neuroendocrine tumours
• Osteosarcoma
• Paranasal meningioma
• Rhabdomyosarcoma
• Squamous cell carcinoma*
• Transitional cell carcinoma
• Transmissible venereal tumour
• Undifferentiated carcinomas*
• Undifferentiated sarcoma

Nasal planum

• Cutaneous lymphoma
• Fibroma
• Fibrosarcoma
• Haemangioma
• Mast cell tumour*
• Melanoma
• Squamous cell carcinoma

Rhinitis* q.v.

3.4.8 Increased radiopacity of the frontal sinuses

Miscellaneous

• Canine leukocyte adhesion deficiency (D)
• Craniomandibular osteopathy

Neoplasia

• Carcinoma*
• Local extension, e.g.
  • Nasal tumour*
• Osteoma
• Osteosarcoma

Obstruction of drainage

• Neoplasia*
• Trauma*

Sinusitis

• Allergic*
• Bacterial*
• Fungal
• Kartagener's syndrome
• Viral*

3.4.9 Increased radiopacity of the pharynx

• Foreign body*
• Mineralisation of laryngeal cartilages
• Nasopharyngeal stenosis
• Obesity*
• Pharyngeal paralysis
• Salivary calculi

Pharyngeal soft tissue mass

• Abscess*
• Granuloma
• Nasopharyngeal polyp*
• Neoplasia
  • Carcinoma
  • Lymphoma

Retropharyngeal mass

• Abscess*
• Enlarged lymph nodes*
• Neoplasia, e.g.
  • Lymphoma*

Soft palate thickening

• Brachycephalic obstructive airway syndrome* (D)
• Mass
  • Cyst
  • Granuloma
  • Neoplasia

3.4.10 Thickening of the soft tissues of the head and neck

Diffuse

• Acromegaly
• Cellulitis*
• Cranial vena cava syndrome
• Neoplasia*
• Obesity*
• Oedema*

Focal

• Abscess*
• Cyst*
• Foreign body*
• Granuloma
• Haematoma*
• Iatrogenic, e.g.
  • Subcutaneous fluid administration*
• Neoplasia*

3.4.11 Decreased radiopacity of the soft tissues of the head and neck

Fat

• Lipoma*
• Obesity*

Gas

• Abscess*
• Perforation
  • Oesophagus
  • Pharynx
  • Skin
  • Trachea
• Pneumomediastinum

3.4.12 Increased radiopacity of the soft tissues of the head and neck

Artefact

Calcification

• Calcinosis circumscripta
• Calcinosis cutis

Calcification of

• Abscess
• Granuloma
• Haematoma
• Tumour

Foreign body*

Iatrogenic

• Barium
• Microchip

Neoplasia

3.5 Radiography of the spine

3.5.1 Normal and congenital variation in vertebral shape and size

Congenital variation

• Abnormal dorsal angulation of the dens of C2
• Agenesis/incomplete development of the dens of C2
• Anomalous development of a transverse process of a lumbar vertebra
• Block vertebrae
• Butterfly vertebrae
• Cervical vertebral malformation–malarticulation syndrome (wobbler syndrome)* (D)
• Chondrodystrophic dwarfism
• Congenital metabolic disease
  • Congenital hypothyroidism
  • Pituitary dwarfism
• Fused dorsal spinal processes
• Hemivertebrae
• Mucopolysaccharidosis
• Narrowed vertebral canal
  • Cervical vertebral malformation–malarticulation syndrome (wobbler syndrome) (D)
  • Congenital lumbosacral stenosis
  • Secondary to hemivertebrae or block vertebrae
  • Thoracic stenosis
• Occipital dysplasia
• Perocormus
• Sacrococcygeal dysgenesis
• Scoliosis
• Shortened dens of C2
• Spina bifida
• Spinal stenosis
• Transitional vertebrae

Normal variation

• C7 may be shorter than adjacent vertebrae.
• L7 may be shorter than adjacent vertebrae.
• Ventral L3 and L4 may be poorly defined.

3.5.2 Acquired variation in vertebral shape and size

Altered vertebral shape

• Hyperparathyroidism
  • Nutritional secondary
  • Primary
  • Renal secondary*
• Hypervitaminosis A
• Mucopolysaccharidosis
• Spondylosis deformans
• Trauma
  • Fracture*

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Metastatic neoplasia*
  • Haemangiosarcoma
  • Lymphosarcoma
  • Prostatic carcinoma
• Multiple cartilaginous exostoses
• Multiple myeloma
• Osteochondroma
• Osteosarcoma*

Decreased vertebral size

• Discospondylitis
• Fracture*
• Intervertebral disc herniation* (D)
• Mucopolysaccharidosis
• Nutritional secondary hyperparathyroidism

Increased vertebral size

• Baastrup's disease
• Bone cyst
• Callus formation secondary to trauma/pathological fracture
• Disseminated idiopathic skeletal hyperostosis
• Hypervitaminosis A
• Mucopolysaccharidosis

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Metastatic neoplasia*, e.g.
  • Haemangiosarcoma
  • Lymphosarcoma
  • Prostatic carcinoma
• Multiple cartilaginous exostoses
• Osteochondroma
• Osteosarcoma*

Spondylitis

• Bacterial, e.g.
  • Foreign body*
  • Haematogenous
  • Puncture wound
• Fungal, e.g.
  • Actinomycosis
  • Aspergillosis
  • Coccidioidomycosis
• Parasitic, e.g.
  • Spirocerca lupi
• Protozoal, e.g.
  • Hepatozoonosis

Spondylosis deformans

• Cervical vertebral malformation–malarticulation syndrome (wobbler syndrome)* (D)
• Chronic disc disease* (D)
• Degeneration of annulus fibrosis
• Discospondylitis
• Hemivertebrae
• Post surgery
• Trauma*

Vertebral canal changes

Widened

• Arachnoid cyst
• Syringohydromyelia
• Tumour

Narrowed

• Adjacent bone pathology, e.g.
• Callus
• Cervical vertebral malformation–malarticulation syndrome (wobbler syndrome)* (D)
• Lumbosacral stenosis

3.5.3 Changes in vertebral radiopacity

Focal or multifocal decrease in radiopacity

• Discospondylitis
• Osteomyelitis*
• Vertebral physitis

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Metastatic neoplasia
• Multiple myeloma
• Osteochondroma
• Osteosarcoma*

Focal or multifocal increase in radiopacity

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Metastatic neoplasia*, e.g.
  • Haemangiosarcoma
  • Lymphoma
  • Prostatic carcinoma
• Osteochondroma
• Osteosarcoma*

Generalised decrease in radiopacity

• Disuse atrophy
• Hyperadrenocorticism
• Hyperparathyroidism
  • Nutritional secondary
  • Primary
  • Pseudohyperparathyroidism*
  • Renal secondary*
• Hyperthyroidism* (C)
• Hypothyroidism* (D)
• Osteogenesis imperfecta
• Senile osteoporosis

Generalised increase in radiopacity

• Osteopetrosis

3.5.4 Abnormalities in the intervertebral space

Disc space – decreased size

• Adjacent hemivertebra
• Adjacent neoplasia
• Artefact
  • Divergence of X-ray beam at periphery of radiograph
  • Positioning artefact
• Cervical vertebral malformation–malarticulation syndrome (wobbler syndrome)* (D)
• Degenerative canine lumbosacral stenosis
• Discospondylitis
• Hansen type I disc extrusion* (D)
• Hansen type II disc protrusion* (D)
• Post surgery
• Spondylosis deformans*
• Subluxation
• Within block vertebra

Disc space – widened

• Normal variation
• Adjacent to hemivertebra
• Artefact (traction)
• End-plate erosion
  • Discospondylitis
  • Neoplasia
• Mucopolysaccharidosis
• Trauma
  • Luxation
  • Subluxation

Increased radiopacity of disc space

• Artefact
  • Superimposition of normal bone/soft tissue
• Incidental mineralisation
• Intervertebral disc disease* (D)

Irregular margination of disc space

• Ageing in cats
• Degenerative intervertebral disc disease
• Discospondylitis
• Mucopolysaccharidosis
• Nutritional secondary hyperparathyroidism
• Spondylosis deformans*

3.5.5 Contrast radiography of the spine (myelography)

Artefact/technical factors

• Contrast medium in soft tissues outside the vertebral canal
• Contrast medium in the spinal parenchyma
• Epidural leakage
• Injection of contrast into the central canal
• Injection of gas into the subarachnoid space
• Subdural injection

Extradural lesions

• Congenital abnormalities
• Foreign body
• Neoplasia

Degenerative

• Hansen type I disc extrusion* (D)
• Hansen type II disc protrusion* (D)
• Hansen type III disc high-velocity low-volume extrusion
• Hypertrophied ligamentum flavum
• Arachnoid cysts

Inflammatory

• Abscess
• Granuloma

Trauma

• Fracture*
• Luxation*

Vascular

• Haematoma
• Haemorrhage

Intradural/extramedullary

Degenerative

• Disc disease

Idiopathic

• Intra-arachnoid cyst

Inflammatory

• Subdural granuloma

Neoplasia

• Lymphoma
• Meningioma
• Nerve root tumour
• Nerve sheath tumour

Vascular

• Subarachnoid haematoma
• Subarachnoid haemorrhage

Intramedullary

Congenital

• Syringohydromyelia* (D)

Degenerative

• Disc disease* (D)

Inflammatory

• Granulomatous meningoencephalomyelitis

Neoplastic

• Ependymoma
• Glioma
• Lymphoma
• Metastatic tumours

Traumatic

• Cord swelling
  • Concussion
  • Disc extrusion

Vascular

• Ischaemic myelopathy*
• Myelomalacia secondary to infarction

Contrast column splitting

• Lateralised extradural compression(s)
• Midline extradural compression

3.6 Thoracic ultrasonography

3.6.1 Pleural effusion

(See Section 3.1.13 for full listings)

• Bile pleuritis
• Blood
• Chyle
• Exudate
• Transudate/modified transudate

3.6.2 Mediastinal masses

• Granuloma
• Idiopathic mediastinal cysts
• Neoplasia
  • Lymphoma*
  • Mast cell tumour
  • Melanoma
  • Thymoma*
  • Thyroid carcinoma
• Reactive lymphadenopathy*
• Thymic branchial cysts

3.6.3 Pericardial effusion

• Secondary to cardiomyopathy (C)*

Haemorrhagic

• Coagulopathy q.v.
• Left atrial rupture

Idiopathic*(D)

Neoplastic*

• Haemangiosarcoma
• Heart base tumours
  • Chemodectoma
  • Metastatic parathyroid tumour
  • Metastatic thyroid tumour
  • Other metastatic tumours*
  • Nonchromaffin paraganglioma
• Lymphoma
• Mesothelioma

Pericarditis

• Bacterial
  • Bite wounds
  • Extension of pulmonary infection
  • Foreign bodies
  • Oesophageal perforation
• Fungal
• Uraemic
• Viral
  • Feline infectious peritonitis* (C)

3.6.4 Altered chamber dimensions

LEFT HEART

Left atrial enlargement

• Chronic bradycardia
• Dilated cardiomyopathy*
• Hyperthyroidism* (C)
• Hypertrophic cardiomyopathy* (C)
• Left-to-right shunt
• Mitral dysplasia
• Myxomatous degeneration of the mitral valve* (D)
• Primary atrial disease
• Restrictive cardiomyopathy (C)

Left ventricle

Dilatation

• Anaemia
• Arteriovenous fistula
• Chronic bradycardia q.v.
• Chronic tachyarrhythmia q.v.
• Dilated cardiomyopathy
  • Drugs/toxins, e.g.
    • Doxorubicin
  • Idiopathic*
  • Parvovirus
  • Taurine deficiency
• High-output states
  • Anaemia* q.v.
  • Hyperthyroidism* (C)
• Myocarditis
• Volume overload
  • Aortic insufficiency
  • Left-to-right shunts
    • Arteriovenous fistulas
    • Atrial septal defects
    • Patent ductus arteriosus
    • Ventricular septal defects
  • Mitral regurgitation, e.g.
    • Mitral dysplasia
    • Myxomatous degeneration of the mitral valve* (D)

Hypertrophy

• Cardiomyopathy
  • Hypertrophic* (C)
• Coarctation of the aorta
• Endomyocardial fibrosis
• Hyperthyroidism* (C)
• Infiltrative cardiac disease, e.g.
  • Lymphoma
• Pressure overload
  • Aortic/subaortic stenosis
  • Systemic arterial hypertension*
• Pseudohypertrophy from volume depletion*

Reduction

• Hypovolaemia q.v.*

Wall thinning

• Aneurysm
• Dilated cardiomyopathy*
• Infarction
• Prior myocarditis

RIGHT HEART

Right atrial enlargement

• Anaemia q.v.
• Arteriovenous fistula
• Atrial septal defect
• Chronic bradycardia
• Cor pulmonale
• Dilated cardiomyopathy*
• Heartworm disease
• Hyperthyroidism* (C)
• Hypertrophic cardiomyopathy* (C)
• Myxomatous degeneration of the tricuspid valve* (D)
• Primary atrial myocardial diseases
• Pulmonary hypertension
• Restrictive cardiomyopathy (C)
• Right-to-left shunts
• Tricuspid dysplasia
• Tricuspid stenosis/atresia

Right ventricle

Dilatation

• Right ventricular volume overload
  • Atrial septal defects
  • Cardiomyopathy
    • Dilated cardiomyopathy* (D)
    • Hypertrophic cardiomyopathy* (C)
    • Restrictive cardiomyopathy (C)
  • Pulmonic insufficiency
  • Tricuspid insufficiency
    • Myxomatous degeneration of the tricuspid valve* (D)
    • Tricuspid dysplasia

Hypertrophy

• Hypertrophic cardiomyopathy* (C)
• Pressure overload
  • Cor pulmonale
  • Heartworm disease
  • Large ventricular septal defect
  • Pulmonary hypertension
  • Pulmonary thromboembolism
  • Pulmonic stenosis
  • Tetralogy of Fallot
• Restrictive cardiomyopathy (C)

Reduction

• Cardiac tamponade
• Hypovolaemia* q.v.

3.6.5 Changes in ejection phase indices of left ventricular performance (fractional shortening, FS%; ejection fraction, EF)

Apparently reduced performance (decreased FS%, decreased EF)

Decreased preload, e.g.

• Hypovolaemia* q.v.

Increased afterload, e.g.

• Aortic stenosis
• Systemic arterial hypertension* q.v.

Reduced systolic function

• Canine X-linked muscular dystrophy
• Chronic valvular heart disease* (D)
• Dilated cardiomyopathy*

Apparently increased performance(increased FS%, increased EF)

Decreased afterload, e.g.

• Hypotension
• Mitral valve regurgitation*

Increased preload, e.g.

• Iatrogenic fluid overload*

Myocardial disease, e.g.

• Hypertrophic cardiomyopathy* (C)

3.7 Abdominal ultrasonography

3.7.1 Renal disease

Diffuse abnormalities

• Renomegaly q.v.
• Small kidneys q.v.

Increased cortical echogenicity with normal or enhanced corticomedullary definition

• End-stage renal disease* q.v.
• Ethylene glycol toxicity
• Fat in the cortex*
• Feline infectious peritonitis* (C)
• Glomerulonephritis
• Interstitial nephritis*
• Nephrocalcinosis
• Lymphoma
• Squamous cell carcinoma

Medullary rim sign

• May be normal*
• Chronic interstitial nephritis*
• Ethylene glycol toxicity
• Feline infectious peritonitis* (C)
• Hypercalcaemic nephropathy
• Idiopathic acute tubular necrosis
• Leptospirosis*

Increased cortical echogenicity with reduced corticomedullary definition

• Chronic inflammatory disease*
• Congenital renal dysplasia
• End-stage kidneys*

Reduced cortical echogenicity

• Lymphoma

Focal abnormalities

Anechoic/hypoechoic lesions

• Abscess
• Acquired cysts secondary to nephropathies
• Congenital cysts
• Cystadenocarcinoma
• Haematoma
• Lymphoma
• Perirenal pseudocyst
• Polycystic kidney disease*
• Tumour necrosis

Hyperechoic lesions

• Calcified abscess
• Calcified cyst wall

Calcified haematoma

• Calculi
• Chronic renal infarcts
• Fibrosis
• Gas
• Granuloma
• Neoplasia
  • Chondrosarcoma
  • Haemangioma
  • Haemangiosarcoma
  • Metastatic thyroid adenocarcinoma
  • Osteosarcoma

Mixed echogenicity lesions

• Abscess
• Acute infarct
• Granuloma
• Haematoma
• Neoplasia
  • Adenocarcinoma
  • Haemangioma
  • Lymphoma

Pelvic dilatation

• Contralateral renal disease/absence (mild dilatation)
• Polyuria/diuresis
• Pyelonephritis
• Renal neoplasia

Congenital conditions

• Ectopic ureter
• Ureterocoele

Hydronephrosis

• Extrinsic mass
• Neoplasia
  • Bladder
  • Prostate
  • Trigone
• Paraureteral pseudocyst
• Ureteral blood clot
• Ureteral inflammation
• Ureteral stricture
• Ureterolith

3.7.2 Hepatobiliary disease

Biliary obstruction (see also Jaundice)

• Abscess
• Biliary calculi
• Gastrointestinal disease* q.v.
• Granuloma
• Hepatobiliary disease* q.v.
• Lymphadenopathy* q.v.
• Neoplasia*
• Pancreatic disease, e.g. pancreatitis*

Diffuse hepatic disease

• Hepatomegaly q.v.*
• Microhepatica q.v.

Decreased echogenicity

• Amyloidosis
• Congestion*
• Hepatitis*
• Leukaemia
• Lymphoma*

Increased echogenicity

• Chronic hepatitis*
• Cirrhosis*
• Fatty infiltration
  • Diabetes mellitus*
  • Obesity*
• Lymphoma*
• Steroid hepatopathy*

Mixed echogenicity

• Cirrhosis*
• Diffuse neoplasia*
• Hepatocutaneous syndrome

Dilatation of the caudal vena cava and hepatic veins

• Haematological disorders
• Systemic infection*

Obstruction of the caudal vena cava/hepatic veins

• Budd–Chiari syndrome
• Liver disease* q.v.
• Neoplasia*
• Strictures
• Thrombosis
• Trauma*

Right-sided heart failure*

• Cardiac tamponade
• Dirofilariasis
• Myocardial disease
• Pulmonary hypertension
• Pulmonic stenosis
• Tricuspid insufficiency

Focal or multifocal hepatic parenchymal abnormalities

• Nodular hyperplasia (D)*

Abscess

• Biliary disease*
• Chronic glucocorticoid administration
• Diabetes mellitus*
• Liver lobe torsion
• Neoplasia*
• Pancreatitis*
• Penetrating foreign body

Cysts

• Acquired cysts
  • Biloma
  • Polycystic renal disease*
• Congenital cysts

Cyst-like masses

• Biliary pseudocyst
• Inflammation
• Necrosis
• Neoplasia*
• Trauma

Haematoma

• Coagulopathy q.v.
• Trauma*

Hepatic necrosis

• Chemical insult
• Immune mediated*
• Infection*
• Toxin

Neoplasia

• Biliary cystadenoma
• Cholangiocellular adenocarcinoma
• Cholangiocellular adenoma
• Hepatocellular adenocarcinoma*
• Hepatocellular adenoma*
• Lymphoma*
• Metastatic tumours*

Focal/multifocal increased echogenicity of the gall bladder

• Biliary calculi
• Gall bladder mucocoele
• Gall bladder sludge*
• Neoplasia
• Polyps

Gall bladder wall thickening

• Acute hepatitis* q.v.
• Cholangiohepatitis*
• Cholecystitis* q.v.
• Chronic hepatitis* q.v.
• Gall bladder mucocoeles
• Hypoalbuminaemia* q.v.
• Neoplasia*
• Right-sided congestive heart failure*
• Sepsis*

3.7.3 Splenic disease

Diffuse splenic disease – splenomegaly

• Amyloidosis
• Extramedullary haematopoiesis
• Immune-mediated disease*
• Infarction
• Parenchymal necrosis
• Portal hypertension
• Splenic vein thrombosis

Congestion

• Anaesthetic agents*
• Haemolytic anaemia*
• Portal vein obstruction
• Right-sided heart failure*
• Torsion of the splenic pedicle
  • Gastric dilatation/volvulus
  • Isolated
• Toxaemia*
• Tranquillizers*

Infection

• Bacterial*
• Fungal

Neoplasia

• Lymphoma*
• Lymphoproliferative disease
• Malignant histiocytosis
• Mastocytosis
• Myeloproliferative disease

Parasites

• Babesiosis
• Ehrlichiosis
• Haemotropic Mycoplasma spp.

Focal or multifocal splenic disease

• Abscess
• Fat deposits
• Nodular hyperplasia

Haematoma

• Abdominal trauma
• Coagulopathy

Infarcts

• Cardiovascular disease*
• Hyperadrenocorticism
• Hypercoagulability
• Inflammatory diseases
  • Endocarditis
  • Pancreatitis*
  • Septicaemia*
• Liver disease* q.v.
• Neoplasia*
  • Fibrosarcoma
  • Haemangioma
  • Haemangiosarcoma
  • Leiomyosarcoma
  • Lymphoma
• Renal disease* q.v.

Neoplasia

• Chondrosarcoma
• Fibrosarcoma
• Fibrous histiocytoma
• Haemangioma*
• Haemangiosarcoma*
• Leiomyosarcoma
• Liposarcoma
• Lymphoma*
• Metastatic tumours*
• Myxosarcoma
• Osteosarcoma
• Rhabdomyosarcoma
• Undifferentiated sarcoma

3.7.4 Pancreatic disease

Focal pancreatic lesions

• Abscess (D)
• Cyst-like structures
  • Congenital cysts
  • Pseudocysts
  • Retention cysts
• Neoplasia
• Nodular changes

Diffuse enlargement

• Pancreatic neoplasia
• Pancreatic oedema
• Pancreatitis*

3.7.5 Adrenal disease

Adrenomegaly

Unilateral

• Adrenal tumour
  • Adrenocortical adenocarcinoma*
  • Adrenocortical adenoma*
  • Blastoma
  • Metastatic tumours
  • Pheochromocytoma

Bilateral

• Adrenal tumours
  • Adrenocortical adenocarcinoma*
  • Adrenocortical adenoma*
  • Metastatic tumours
• Drugs
  • Trilostane
• Hyperplasia
• Pituitary-dependent hyperadrenocorticism*
• Stressful non-adrenal illness*

3.7.6 Urinary bladder disease

Increased wall thickness

Diffuse

• Chronic cystitis*
• Emphysematous cystitis
  • Clostridial infection
  • Diabetes mellitus
• Empty bladder*
• Fibrosis/calcification of the bladder wall

Focal or multifocal

• Mural haematomas
  • Coagulopathy q.v.
  • Iatrogenic
  • Infection
  • Neoplasia
  • Trauma
• Neoplasia
  • Adenocarcinoma
  • Chemodectoma
  • Fibroma
  • Fibrosarcoma
  • Haemangioma
  • Haemangiosarcoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma
  • Myxoma
  • Rhabdomyosarcoma
  • Squamous cell carcinoma
  • Transitional cell carcinoma
  • Undifferentiated carcinoma

Focal wall defects

• Acquired diverticulum
• Patent urachus
• Urachal diverticulum
• Ureterocoele

Intraluminal lesions, e.g.

• Blood clots*
• Foreign bodies
• Gas bubbles
• Sediment*
• Uroliths*

3.7.7 Gastrointestinal disease

Increased wall thickness

Diffuse

• Acute haemorrhagic gastroenteritis*
• Colitis* q.v.
• Gastritis*
  • Dietary*
  • Infectious*
    • Parvovirus*
  • Inflammatory*
  • Uraemic* q.v.
• Inflammatory bowel disease*
• Neoplasia
  • Lymphoma*

Focal/multifocal

• Benign adenomatous polyps
• Chronic hypertrophic gastropathy
• Congenital hypertrophic pyloric stenosis
• Inflammatory bowel disease*
• Intussusception (apparent)
• Neoplasia
  • Adenocarcinoma
  • Adenoma
  • Carcinoid tumours
  • Carcinoma
  • Leiomyoma
  • Leiomyosarcoma
  • Lymphoma
  • Neurilemmoma

Decreased intestinal motility (ileus)

Functional

• Abdominal pain*
• Acute gastroenteritis*
• Amyloidosis
• Neurogenic disease
• Oedema
• Post-operative abdomen*
• Vascular disease
• Drugs

Mechanical

• Adhesions*
• Foreign body*
• Intussusception
• Localised inflammation*
• Neoplasia

3.7.8 Ovarian and uterine disease

Ovarian masses

• Ovarian stump granuloma

Cysts*

• Follicular
• Luteinising

Neoplasia

• Adenoma
• Adenocarcinoma
• Dysgerminoma
• Granulosa cell tumour
• Luteoma
• Teratoma
• Thecoma

Uterine enlargement

• Haemometra
• Hydrometra
• Mucometra
• Post partum*
• Pregnancy*
• Pyometra*

Uterine wall thickening

Neoplasia

• Adenocarcinoma
• Adenoma
• Fibroma
• Fibrosarcoma
• Leiomyoma
• Leiomyosarcoma
• Lymphoma

3.7.9 Prostatic disease

Prostatic enlargement

Diffuse

• Bacterial prostatitis*
• Benign prostatic hyperplasia*
• Neoplasia
• Squamous metaplasia

Focal lesions

• Abscessation
• Cysts
  • Paraprostatic
  • Prostatic
• Neoplasia
  • Adenocarcinoma
  • Fibroma
  • Leiomyoma
  • Leiomyosarcoma
  • Squamous cell carcinoma
  • Transitional cell carcinoma
  • Undifferentiated carcinoma

3.7.10 Ascites

Bile – ruptured biliary tract

• Neoplasia
• Post surgery, e.g.
  • Cholecystectomy
• Severe cholecystitis*
• Trauma

Blood

• Coagulopathy
• Neoplasia, e.g.
  • Haemangiosarcoma*
• Organ or major blood vessel rupture
• Thrombosis
• Trauma
• Vasculitis

Chyle

• Congestive heart failure
• Feline infectious peritonitis (C)
• Lymphangiectasia
• Lymphangiosarcoma
• Lymphoma
• Mesenteric root strangulation
• Ruptured cisterna chyli
  • Neoplasia
  • Trauma
• Steatitis

Exudate

• Diaphragmatic hernia
• Feline infectious peritonitis* (C)
• Hepatitis
• Neoplasia
• Organ torsion
• Pancreatitis
• Pericardiodiaphragmatic hernia

Septic peritonitis

• Abscess
• Haematogenous spread
• Iatrogenic/nosocomial
• Local extension of infection from elsewhere
• Migrating foreign body
• Neoplasia*
• Pancreatitis*
• Penetrating wound
• Primary
• Ruptured viscus, e.g.
  • Neoplasia
  • Post surgery, e.g.
    • Enterotomy wound dehiscence*
  • Pyometra
  • Trauma
• Steatitis

Transudate/modified transudate

• Cardiac tamponade q.v.
• Caudal vena caval obstruction
• Hepatic disease
  • Cholangiohepatitis* q.v.
  • Chronic hepatitis* q.v.
  • Cirrhosis*
  • Fibrosis*
  • Portal hypertension
• Hypoalbuminaemia* q.v.
• Inflammation
  • Feline infectious peritonitis
• Neoplasia*
• Portal hypertension
• Right-sided heart failure*
• Ruptured cyst
• Splenic disease

Urine – lower urinary tract rupture

• Bladder
• Ureter
• Urethra

3.8 Ultrasonography of other regions

3.8.1 Testes

Enlargement

• Neoplasia*
• Orchitis
• Torsion

Focal lesions – neoplasia

• Interstitial cell tumour*
• Seminoma*
• Sertoli cell tumour*

3.8.2 Eyes

Intraocular masses

• Foreign body*
• Inflammation*

Infection*

• Bacteria
• Fungi
  • Blastomycosis
  • Coccidioidomycosis
  • Cryptococcosis
  • Histoplasmosis
• Viral
  • Feline infectious peritonitis* (C)

Neoplasia

• Ciliary body adenocarcinoma
• Ciliary body adenoma
• Lymphoma
• Medulloepithelioma
• Melanoma
• Metastatic cancer
• Squamous cell carcinoma

Organised haemorrhage*

• Chronic glaucoma
• Coagulopathy q.v.
• Diabetes mellitus*
• Hypertension* q.v.
• Neoplasia
• Neovascularisation
• Persistent hyaloid artery
• Trauma*
• Vitreoretinal disease

Point-like and membranous lesions of the vitreous chamber

• Asteroid hyalosis
• Endophthalmitis
• Foreign body
• Haemorrhage (see preceding text)
• Persistent hyperplastic primary vitreous
• Posterior vitreal detachment
• Vitreous floaters
• Vitreous membrane formation

Retinal detachment q.v.

Retrobulbar masses

Abscess/cellulitis*

• Extension from nasal cavity
• Extension from paranasal sinuses
• Extension from tooth root infection*
• Extension from zygomatic salivary gland
• Foreign body
• Haematogenous spread
• Oral inflammatory disease
• Penetrating wound

Neoplasia

• Metastatic tumours
• Chondrosarcoma
• Haemangiosarcoma
• Lacrimal gland tumour
• Lymphoma
• Meningioma
• Nasal adenocarcinoma
• Neurofibrosarcoma
• Osteosarcoma
• Rhabdomyosarcoma
• Squamous cell carcinoma
• Zygomatic gland tumour
• Primary epithelial and mesenchymal tumours

3.8.3 Neck

Enlarged parathyroid gland(s)

Neoplasia

• Adenocarcinoma
• Adenoma

Hyperplasia

• Nutritional secondary hyperparathyroidism
• Renal secondary hyperparathyroidism

Enlarged thyroid gland(s)

Miscellaneous

• Thyroid cyst
• Thyroiditis

Neoplasia

• Adenocarcinoma*
• Adenoma*

Lymph node enlargement

Inflammation/infection

• Abscess*
• Inflammation*

Neoplasia

• Lymphoma*
• Metastatic neoplasia*

Salivary gland enlargement

• Salivary cysts
• Retention cyst
• True cyst
• Salivary gland abscess*
• Salivary gland neoplasia
• Sialadenitis/sialadenosis
• Sialocoele*
• Sialolithiasis

Neck masses at other sites

Inflammation/infection

• Abscess*
• Cellulitis
• Granuloma

Neoplasia

• Lipoma*
• Metastatic neoplasia
• Primary neoplasia

Miscellaneous

• Arteriovenous malformation
• Cyst*
• Haematoma*