“See the CXR in 2D but think in 3D” Dr. Markin
Always have a systematic way to interpret a CXR.
Quality of the Film
Is it under/over exposed?
Does the view show the whole lung?
What is the view of the film?
Is it a posterior/anterior (PA = 6ft))or anterior/posterior film (AP=4ft) <- mostly portable films. The heart appear larger (magnified in the AP film)
Additional views o Decubitus - useful for differentiating pleural effusions from consolidation
(e.g. pneumonia) and Loculated effusions from free fluid in the pleura. In effusions, the fluid layers out (by comparison to an up-right view, when it often accumulates in the costophrenic angles). o Lordotic view - used to visualize the apex of the lung, to pick-up abnormalities such as a Pancoast tumour. o Expiratory view - helpful for the diagnosis of pneumothorax o Oblique view
Tubes and Lines
ET tubes, ECG leads, CVP lines, Groshong or pic lines
Look at mediastinal structures
C ardiac silhoutte, detecting cardiac enlargement
Airways, including hilar adenopathy or enlargement
E dges, e.g. apices for fibrosis, pneumothorax, pleural thickening or plaques
F ields (lung parenchyma), being evidence of alveolar filling . Look back and forth to see if the images match back and forth.
F ailure, e.g. alveolar air space disease with prominent vascularity with or without pleural effusions
Below the diaphragm
D iaphragm, e.g. evidence of free air
C ostophrenic angles, including pleural effusions
Soft Tissues and Bones
B ones, e.g. rib fractures and lytic bone lesions
E xtrathoracic tissues
B reast shadows
What is the reasons for the CXR
Position of a line or tube
Evaluation of the pattern of the disease
Progression of the disease
Silhouette sign: Silhouette sign is extremely useful in localizing lung lesions. (e.g. loss of right heart border in RML pneumonia)
Air Bronchogram: As the bronchial tree branches, the cartilaginous rings become thinner and eventually disappear in respiratory bronchioles. The lumen of bronchus contains air as well as the surrounding alveoli. Thus usually there is no contrast to visualize bronchi. If you see branching radiolucent columns of air corresponding to bronchi , this usually means air-space (alveolar) disease. Usually one of these: blood, pus, mucous, cells, protein.
Extra pleural sign: Signifies Chest Wall disease. Peripheral location with concave edges.
Anatomic landmarks o o
Anterior & Posterior junction lines: respectively, the anterior and posterior conjunction of the right and left visceral and parietal pleural layers at the midline of the thorax.
2mm linear line projecting over the trachea. Note the posterior junction line extends above the clavicles