Chest X Rays Flashcards
What are the 2 types of CXRs and which is better quality
PA projection - from standing, better quality
AP projection - from sitting, heart is magnified as farther from receptor so more divergence of X-rays
What is included in a CXR
1st rib to Costophrenic angles
Lateral margins of ribs
What does adequacy depend on
Rotation - spinous process visible between medial parts of clavicles
Inspiration - 5-7th anterior ribs at mid Clavicular lines
Penetration - spinous process visible through heart shadow and entire left hemidiaphragm is visible
Describe ABCDE approach
Airways - trachea, bronchi and hila
Breathing - lungs, pleural spaces, lung interfaces
Circulation - aortic knuckle, heart borders, pulmonary vessels
Diaphragm and bones - free gas, fractures, elevated/depressed diaphragm
Everything else
What is a silhouette sign
Silhouette formed between adjacent structures of differing density
Where silhouette sign is lost, there is a pathology
Give examples of where silhouette sign is lost and where the pathology responsible is
Right heart border - right middle lobe
Left heart border - left upper lobe (lingula)
Paratracheal stripe - mediastinum
Chest wall - lung, pleura, ribs
Diaphragm - lower lung lobes
Aortic knuckle - anterior mediastinum or left upper lobe
Horizontal fissure - right upper lobe
Describe mediastinal shift
Deviation of trachea/heart
Push: increased pressure or volume e.g tension pneumothorax, pleural effusion
Pull: decreased pressure or volume e.g fibrosis, iatrogenic, lung collapse
What is a pneumothorax
Air in the pleural space
Types of pneumothorax
Primary spontaneous - usually trauma (look for complications of fracture)
Secondary spontaneous - emphysema, asthma, Marfan’s
Iatrogenic
Tension pneumothorax
What is a tension pneumothorax
Depressed hemidiaphragm on the affected side AND a mediastinal shift away from the pneumothorax
What is a large pneumothorax
> 2cm from inner chest wall at level of the hilum
Symptoms of a pneumothorax
Pleuritic chest pain
Dyspnoea
How do you investigate a pneumothorax
Past medical history - underlying condition, previous surgery
CXR unless tension pneumothorax (not enough time)
Treatment of pneumothorax
Discharge if no SOB
Aspiration for primary and small secondary pneumothorax
Intercostal chest drain if aspiration fails, large secondary and tension pneumothorax
What is pleural effusion
Collection of fluid in the pleural space
Types of pleural effusion
Haemothorax (blood)
Chylothorax (chyle)
Empyema (pus)
Simple effusion (serous fluid)
Appearance of CXR in pleural effusion
Uniform white area
Meniscus
Loss of Costophrenic angles
Obscured hemidiaphragm
Types of simple effusions and how are each caused
Transudate - high venous pressure or low oncotic pressure (pleural protein:serum protein >0.5)
Exudate - infection, RA, malignancy of pleura, ascites
What is atelectasis
Volume loss within lung lobe
Causes of atelectasis
Luminal - mucous plugging, aspirated foreign material, iatrogenic)
Mural - bronchogenic carcinoma
Extrinsic - compression
CXR features of atelectasis
Hemidiaphragm elevation on affected side, mediastinal shift towards collapse, crowding of ribs and pulmonary vessels
What is consolidation
Airways filled with pus, fluid (oedema, blood) , cells
What cause space occupying lesions
Malignancy Benign masses Inflammation e.g TB granulomas Congenital Artefact
What is the normal cardiac index and how is it measured
On a PA projection
Cardiac:thoracic <0.5
