Appendix 1 Radiology Flashcards
Chest Radiograph
It is customary to follow a systematic approach in the study of a
chest X-ray to ensure thoroughness and accuracy.
This task is based on careful observation,
sound anatomical principles, and
good pathophysiological knowledge.
Identify patient details and date of exam
Please Rest In Peace (P RIP)
ABCDE – BIT
- Projection
- Rotation
- Inspiration
P – Projection
This is written on the film. The different projections of importance to
us are Postero Anterior (PA), Antero Posterior (AP), Lateral, Supine,
and Lateral decubitus.
Fig. 1 PA view Fig.
Less magnification of mediastinal structures
Scapula is rotated out so the lung fields are clear
2 AP view
All anterior structures appear magnified—heart,
mediastinum, sternum, clavicles, and ribs.
Lateral—helpful in viewing retrosternal and chest wall lesions
Lateral decubitus—used in diagnosing very small collection of air or
fluid in the pleural space.
R – Rotation
An image is not rotated if the clavicular heads are equidistant to the
corresponding thoracic spine.
I – inspiration
An inspiratory picture shows a ‘lot of lung’. In inspiratory films the
level of the diaphragm is at the level of ribs 5/6 anteriorly and 8/10
posteriorly. (AR6PR10)
P – Penetration
A film is adequately penetrated if the vertebral bodies can be
visualised against the cardiac silhouette.
ABCDE – BIT approach
ABCDE – BIT approach
A: Airway (trachea, bronchi, and hila)
B: Breathing (lungs and pleura)
C: Circulation (heart and mediastinum)
D: Diaphragm
E: Everything else!
Bone, Intervention, Tissue
A
a—Trace the trachea down to the hila looking for shifts, foreign
bodies, and abnormalities.
B
B—Lung and pleura
Lung—Scrutinise the lung margin clearly and then scan both lungs
starting at the apices and working down, comparing left with the
right at each level.
Pleura—Normally invisible but become visible in fluid collections, and
pleural plaques and pleurally based masses.
C
C—Heart and mediastinum
Heart—Trace the borders of the heart. (See picture 30)
Right heart border is formed predominantly by the right atrium along
with the lower part of SVC, whilst the left border is formed by the
aortic arch, pulmonary artery, left atrium, and ventricle.
The right and left ventricle forms the inferior border.
Cardiothoracic ratio (CT ratio)—The width of the heart should be no
greater than 50% of the width of the rib cage.
Do not forget to look behind the heart!
Mediastinum—Look for superior, anterior, and posterior mediastinal
masses.
D—Diaphragm
The right diaphragm is normally higher than the left due to the
liver.
Trace the hemidiaphragms and compare them for symmetry
and sharpness and then the costo- and cardio-phrenic angles for
obliteration or radiolucency.
Do not fail to look below the diaphragm!
e—Everything else
- Bones—ribs, sternum, scapula, clavicle, spine, and humerus for deposits and fracture
- intervention—tubes and lines, chest drains, pacemakers, and metallic valves
- tissue—skin and chest wall for surgical emphysema;
breast and axilla for previous operations
A normal chest radiograph can be summarised as
‘…the trachea is central and the hila are normal. Lung fields are clear
with no air or fluid collection.
Heart and mediastinum appear normal
and not displaced. There is no free air under the diaphragm, and the
angles are clear.
Also, the bones and soft tissues appear normal…’
Before diagnosing a CXR as normal, look at the areas where pathology is commonly missed.
Commonly missed areas/review areas
Apices (including behind the 1st rib and clavicle)—small pneumothoraces and masses
Hila—masses and lymph nodes; left hilum is 1–2 cm higher than right
Behind the heart—left lower lobar collapse and hiatus hernia
Below the diaphragm—free gas
Soft tissues—breast shadow or absence (look for lung and bone metastasis)
some terms before we discuss different pathology.
silhouette sign
Explains the loss of the silhouette or lung-tissue interface due to any
pathology that replaces the normal air-filled lung.
Normally, if an intrathoracic opacity is in anatomical contact with the
heart border, then the opacity will obscure that border.
e.g. Heart, aorta, and diaphragm.
If an intrathoracic opacity is in the posterior pleural cavity so not
in direct anatomical contact with the heart border, this causes an
overlap but not an obliteration of that border.
e.g. Heart border is obscured in RML collapse
but not obscured in LLL collapse.
Air bronchogram
On a normal CXR, the wall of the bronchi are not normally visible
unless seen end on.
When the alveoli no longer contain air and
opacify, the air-filled bronchi passing through the alveoli may be
visible as branching linear lucencies.
Air bronchograms can be seen in consolidation, collapse, pulmonary
oedema, and severe interstitial lung disease.
