Please enable JavaScript.
Coggle requires JavaScript to display documents.
chest X-ray, Lung fields, Shadows caused by collapsed lung tissue may not…
chest X-ray
- X-ray findings tend to lag behind other
measurements
eg: they are a later
indication of chest infection than pyrexia,
and pneumonia may have been resolved for
days or even weeks while X-ray Signs still
linger
- A normal radiograph does not rule out
disease because its contribution is structural
only
eg:
- the physical damage of emphysema is more apparent than the hypersecretion of chronic bronchitis because secretions do not show on X-ray, and
- postoperative patients with impaired oxygenation may have a normal film
- The 2D representation of a 3D object can obscure the relationship between certain structures and hinder the accurate location of lesions.
- ideally a good x ray is
taken in
- a posteroanterior (PA) view
-
- the patient taking a deep breath in the standing
position with shoulders abducted
-
For less mobile patients
- a portable film is taken,
- with the rays passing anteroposteriorly (AP),
- and the patient sometimes unable to take a
deep breath.
- The heart is magnified by 15-20%
- the anterior ribs are less clear and
- the lung fields are partly obscured by the scapulae and a raised diaphragm.
- Pleural effusions appear as non-specific homogenous densities that are difficult to identify, although they differ from parenchymal densities in that vascular markings are visible through the
density.
- Whether patients are slumped ('erect
portable' film) or supine, results are similar.
- Dense structures absorb rays and are opaque,
- while air has a low density and appears black.
- Allowance should be made for normal variations
between individuals such as different-shaped
diaphragms.
- Chest films show bilateral symmetry
for many structures, enabling opposite sides to
be compared.
-
- A systematic approach is necessary to avoid
becoming diverted by the first obvious abnormality. - With practice this takes 30 seconds.
- Previous films should be available for comparison.
- It is useful to observe first from a distance and then close up
- Preliminary checks
- trachea
- heart
- The patient's name and the date should be
checked.
- Then the projection is noted to see
whether it is a PA or AP film.
- The exposure is then checked.
- 2 more items...
-
-
, sandwiched between the lungs, is the
main occupant of the mediastinum.
- The transverse diameter is normally less
than half the internal diameter of the chest in
the PA film.
A narrow heart
-
-
4.Hila
-
Hila are elevated
- 2 more items...
-
-
-
The bones are examined with care following
- cardiopulmonary resuscitation or
- other trauma,
- or if the patient is suspected of having OP or
- malignant secondary deposits.
A fresh rib fracture
- is seen as a discontinuation of the
border of the rib,
- to be distinguished from overlapping structures that can be misleading
-
Extrathoracic tissues cause shadows that project
onto the lung fields and can cause confusion unless the origin is identified
Breast shadows
may obscure the costophrenic angles in obese
people,
and rolls of fat pressed against the plate
may be visible.
A nasogastric tube
is identified by
- its thin radio opaque line and
- should pass into the stomach.
-
A lateral film shows the lungs
superimposed on each other so that various
structures are either more or less distinguishable
than in the PA film.
Lesions that were concealed behind the
diaphragm or heart are now apparent, e.g. :
- lower lobe collapse may appear as a white
triangle at the costophrenic angle
.
- a pleural effusion of just 50 mL can now
blunt the cos to phrenic angle
.
- if the oblique fissure is visible, any lesion
behind it is in the lower lobe.
Lateral films are also useful if accurate postural drainage is required,
e.g. for an abscess
-
If a patient has fractured ribs and the film has
not yet been reported,
it is advisable to ask a
radiologist to check the film before contemplating any positive pressure treatment
-