X-Ray interpretation Flashcards
What anatomy can you see on a CXR?
Trachea Hila Lungs Diaphragm Heart Aortic knuckle Ribs Scapulae Clavicles
What is the structure of interpreting CXR’s?
Confirm details Assess image quality Obvious abnormalities ABCDE approach Review areas
What pt details are important?
Projection
Name, DOB, ID no.
Date and time
Previous films
What do you look for when assessing image quality?
Rotation
Inspiration
Projection
Exposure
‘Well inspired, non-rotated, well penetrated Xray with adequate exposure’
How do you assess rotation?
Medial aspect from each clavicle should be equidistant from spinous processes
Spinous processes should be vertically orientated against the vertebral bodies and lie halfway between the clavicles
How do you asses inspiration?
5-6 anterior ribs
10 posterior ribs
Costophrenic angles and lateral rib edges should be visible
What do you check re projetion?
AP or PA
Should be labelled but if not labelled assume PA
AP - scapula within lung field and enlarged mediastinum
What does projection matter?
Size of the heart will be different
Larger on AP
What is important re exposure?
Left diaphragm should be visible to the spine
Vertebrae should be visible behind the heart
Make sure there is adequate penetration
How should you describe the obvious abnormalities?
Site? - which lung, which lung lobe/part?
Size?
Shape? - round, diffuse, well/poorly demarcated, focal, diffuse
Density? - more or less compared to surrounding tissue
Texture? - uniform or heterogenous
Number and distribution? - single/multiple or focal/widespread
Other features? - fluid levels, air bronchograms, bony changes, equipment
What is A in the A-E approach?
Airway
Trachea? - central or deviating
Pushing or pulling
Carina
Lung hilar
What causes deviation away from the lesion?
Pleural effusion
Mass
Tension pneumothorax
What causes deviation towards from the lesion?
Volume loss e.g. consolidation or collapse
What are the differences between the right and left bronchus?
Right bronchus is wider than left
Foreign objects usually go via the right
Why is the carina significant?
Where left and right bronchi form
Landmark for NG tube placement
NG should bisect the carina, you know it is not in the airway
What comprise the lung hilar?
Major bronchi
Pulmonary vessels
Lymph nodes
What causes lung hilar enlargement?
malignancy (unilateral), sarcoidosis (bilateral_
What is B in the A-E assessment?
Breathing
How do you assess breathing?
Lung fields
Start in apices, work down to costophrenic angles
Compare both lungs as you do
What do marking indicate?
Increased air space shadowing - consolidation
Absence of markings - pneumothorax
Give an example of how you would describe consolidation?
Large area of patchy air space shadowing near the right border of the heart
Suggestive of consolidation
What is C in the A-E assessment?
Cardiac
Heart size and borders
‘cardiothorocic ratio and cardiophrenic angle’
How do we assess heart size?
heart should occupy no more than 50% of the thoracic width
What conditions can cause cardiomegaly?
HF, valvular heart disease, cardiomyopathy, pulmonary hypertension and pericardial effusion
How do we assess heart borders?
Well-defined
The right atrium makes up most of the right heart border.
The left ventricle makes up most of the left heart border.
What is reduced definition of the right heart border commonly associated with?
typically associated with right middle lobe consolidation
What is reduced definition of the left heart border commonly associated with?
Typically associated with lingular consolidation
What is D in the A-E assessment?
Diaphragm
Height
Under
Costophrenic angles
What does a normal diaphragm look like?
Right normally higher
Curved
What does flattening of the diaphragm’s mean?
Suggest lung hyper-expansion
Air-trapping COPD
What should you check for under the diaphragm?
Free air under the diaphragm
Pneumoperitoneum
Can cause right hemidiaphragm to lift and visibly separate from the liver
Air will look black under a thin white line which is the diaphragm
What commonly causes pneumoperitoneum?
Bowel perforation
What are you looking for in the costophrenic region?
Well defined acute angle
Loss of this is known as costophrenic blunting
What can cause blunting of the costophrenic angles?
Fluid
Consolidation
What is E?
Everything else
Bones - fractures, lesions
Soft tissues - surgical emphysema, clips, masectomy
Equipement - NGs, pacemakers
What is surgical emphysema?
Air in the soft tissue
Usually resolves by itself
What can cause surgical emphysema?
After surgery, insertion of chest drain, NIV
What ares of interpretation are commonly missed?
Apices
Hilar
Behind the heart
Under the diaphragm
What is the key difference between pneumothorax and tension pneumothorax
Tension you get entire shifting of mediastinum
What are the signs of lung collapse?
Loss of volume
Raised hemidiaphragm ipsilaterally
Tracheal and medistinal shift towards the collapsed side
Narrowing of the space between the ribs compared to other side
Homogenous opacity
What are the signs of pleural effusion of CXR?
Blunting of the costophernic angles
Homogenous opacification
Fluid level manifesting as a meniscus
What are the main features of tension pneumothorax
Significant mediastinal shift
Depressed hemidiaphragm
Lung collapse?
Medical emergency
Diagnosed clinically and treated immediately with needle thoracentesis
Never diagnosed on CXR
What is the structure for interpreting AXR’s?
Confirm details Assess image quality Obvi Bowels Bones Calcification (and artefact)
How do we assess quality on a AXR?
Projection:
Most of them are AP with pt. lying flat
Decubitas - used in paeds
Exposure:
Ensure whole abdomen is visible, from level of hemidiaphragm to bowel
If bowel perforation is suspected what is the best imaging?
Errect CXR must be done
Must sensitive at detecting the presences of free gas in abdomen
What are the typical characteristics of the large bowel?
Typically runs around outside of abdomen Follow along (rectum --> caecum)
May contains faeces which will appear as mottled due to gaseous content
Diameter no wider than 6cm
Caecum can be up to 9cm
Haustra and haustral folds
What are haustra/haustral folds?
Haustral folds represent folds of the mucosa
within the colon
Hastra refer to the small segemented pouches of bowel separated by haustral folds
What are the typical characteristics of small bowle?
Lies centrally
Diameter should be no wider than 3cm
Valvulae conniventes
- thin, circular folds of mucose
What are the features of small bowel obstruction on a AXR?
Dilation of the small bowel <3cm
More prominent vavulae conniventes
What are the causes of small bowel obstruction?
Adhesions (75%) post surgery
Hernias
Malignancy
What are the features of large bowel obstruction?
Colonic distention > 6cm
May cause small bowel dilatation in prolonged obstruction or poor competence of the ileo-caecal valve
What are some causes of large bowel obstruction?
Colorectal cancer
Diverticulitis
Volvulus
What do you see on a AXR in sigmoid volvulus?
Coffee bean sign
What can you see when there is air in the abdomen?
Both sides of the bowel wall become visible
Known as Rigler’s sign
What are the causes of penumoperitoneum?
Perforated bowel
Perforated duodenal ulcer
Recent abdominal surgery
What are features of IBD on AXR?
Thumb-printing: mucosal thickening due to inflammation and oedema, appears like thumbprints projecting inwards
Lead pipe: Loss of normal haustral markings
Toxic megacolon: colonic dilatation
What other organs should you check on a AXR?
Lung - inspect bases
Liver - evidence of hepatomegaly
Gallbladder - gallstones, but most are radiolucent
Kidneys - both should be visible
Bladder - variable appearance depending on how full
What bones might you visualise on a AXR?
Ribs Lumbar vertebrae Sacrum Coccyx Pelvis Proximal femurs
What artefact may you see on a AXR?
Surgical clips
Jewellery
Indwelling lines
Surgical lines
What calcification might be seen on a AXR?
Calcified gallstones in the right upper quadrant Renal stones/staghorn calculi Pancreatic calcification Vascular calcification Costochondral calcification
What are the 3 types of shadowing?
Alveolar ‘fluffy’ - pneumonia
Homogenous - Pleural effusion
Reticulonodular
How do you diagnose cause of pleural effusion?
Pleural tap
Exudate (high protein) vs Transudate
What do you see on CXR in pulmonary odema?
Bat’s swing airspace shadowing
What external objects could be seen on CXR?
Metallic valves
Sternotomy wires
Pacemaker
What can cause pulmonary odeoma?
ARDS
Pulmonary hypertension
HF
When might you see batswing shadowing?
Pulmonary odema
ILD
What might cause coin lesions?
Malignancy TB Abscess Cyst Benign tumour e.g. schwannoma
What are causes of bihilar lymphadenopathy?
Sarcoidosis TB AIDS Recurrent Chest Infections Tumours e.g. lymphoma
What are causes of unilateral hilar lymphadenopathy?
TB
AIDS
Recurrent Chest Infections
Tumours e.g. lymphoma
What is the difference between Sarcoidosis and TB?
TB - caseating granulomas
Sarcoidosis - non-caseating
What are multiple coin lesions called?
Canonball mets
seen in renal cancer
can also be caused by prostate cancer
What can cause a widening of the mediastinum?
Aortic aneurysm/dissection
Goitre
Lymphoma
