Chest x-ray (CXR) interpretation
Done quickly first check the film details and orientation.
Then use the ABCDEFGHI approach…
A- Airway: is the trachea central? Is the carina visible? Is it pulled to one side or
another?
B- Bones: all present no fractures
C- Cardiac: the shadow should be less than 50% the diameter of the diaphragm.
D- Diaphragm: are both sides level? are the angles sharp and clearly defined?
E- Extras: are there any extra lines or devices on the patient?
F- Lung Fields: look in turn at the upper, middle and lower lung fields, are there any
consolidations?
G- Gastric bubble: should be seen below the left diaphragm
H- Hilum: (area in the middle of the x-ray above the heart) is it bulky, ?venous
congestion? Lymph nodes
I- Inspiration: can you see 8-10 ribs,
Once completing the assessment summarise your positive findings.
In detail ABCDEFGHI approach…
Check details
Orientation and assessing film quality
Look for a marker, (L or R). the heart should have the apex on the left, the gastric bubble
should also be on the left.
Most chest x-rays are done from back to front (posterior to anterior PA) if it is not PA
the heart will be artificially large.
The patient should be sat up in the film any effusion is at the bottom of the lungs. They
should have taken a deep breath. Penetration should be adequate to see the spine
behind the heart but not in detail.
A- Airway
The trachea should be central, it can be tugged towards an aera of
collapsed lung or pushed away from a pneumothorax or pleural effusion.
B- Bones
Check the bones have no fractures, follow their outlines round.
C- Cardiac
The heart should be less then 50% the diameter of the chest, roughly two
thirds should be on the left side whilst one third should be on the right.
Enlarged heart could be due to heart failure or hypertension. If the heart is
Provided by T. Whitfield 2012
globular in shape or especially large it may be due to pericardial effusion.
You cannot comment on the heart size in an AP film.
D- Diaphram
This should be roughly level on both sides, the costa-phrenic and cardiophrenic angles should be sharp and easily defined. Blunting of a diaphragm
occurs in pleural effusion, pleural effusion starts on the edge of the
diaphragm first, if it is due to a transudate cause it will usually start on the
right first. The diaphragm can tent on one side to a ^ shapecaused by a
collapse of some of the lung. There may be air under the diaphragm if the
bowel has perforated or their has been recent surgery.
E- Extra’s:
Such as chest drain lines, NG tubes, Bra strap clips or a pacemaker.
F- Lung Fields
Check each lung field systematically upper, middle and lower. Look for
consolidation comparing like with like. Fluids and consolidations are
white. Fluid is very dense at least as white as the heart. Consolidation may
have black holes of cavitation in it note how solid it is, the extent and
distribution. Check the periphery of the lungs for any sign of
pneumothorax which is a line in the pleural cavity where the lung finishes.
G- Gastric bubble
Should be present under the left of the diaphragm.
H- Hilum
Enlarged lymph nodes can be seen at this region they add an extra
bulkiness, these are seen in TB and cancer. The pulmonary arteries and
veins enter and leave the heart in this area these may be swollen in heart
failure.
Pathology is easily missed in the following regions:
Apices
Lung peripheries
Hemidiaphragms
Behind the heart
Provided by T. Whitfield 2012
Further notes to consider
Consolidation
A thick area of white on an x-ray is termed a consolidation. If this is due to fluid it will sit
at the bottom of the lung obliterating the line of the diaphragm at the bottom to
whatever level it reaches. The fluid will rise as the surface meets the edge of the pleura.
Consolidation usually refers to whitened areas anywhere in the lung field. The more
white the consolidation the more dense it is.
It can be difficult to distinguish the cause of consolidations on an x-ray and history can
be of great assistance in interpreting a chest x-ray.
Pneumonia usually gives rise to a hazy consolidation in one specific lung field i.e left
base or right apex. Pneumonias in more than one area of a lung would make a very ill
patient.
TB can cause multiple x-ray patterns primary TB shows apical consolidation with
cavitation (black area in the middle). Other forms of TB can show extensive
consolidation throughout the lung with cavitation and lymph nodes, the patient will not
appear drastically ill. Millary TB causes reticulonodular shadowing throughout all lung
fields (dots all over the x-ray).
Pneumocystis jiroverci will give rise to a ground glass appearance on the chest x-ray
(general haziness all over) this can be fit with a picture of hypoxia on exertion and
shortness of breath with a dry cough.
Collapse of the lung
Collapse of a lobe (atelectasis) may be difficult to see, it may cause a raising of one side
of the diaphragm and pull other structures towards it. Collapse can also cause a
consolidation of the affected area.
Provided by T. Whitfield 2012