Introduction to CXRs - Friday, 13 November 2026, 5.30pm, Self-Directed Learning (SDL)

Introduction to CXRs 

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A chest X-ray (CXR) is a quick, non-invasive imaging test that uses a small dose of radiation to create pictures of the heart, lungs, blood vessels, airways, and chest bones. [1]

How It Works (Image Densities)

X-rays pass through the body differently depending on tissue density: [1]

• Air (Black): Least dense; lungs appear dark because X-rays pass right through.
• Bone/Metal (White): Most dense; ribs, spine, and medical devices block X-rays and show up bright white.
• Soft Tissue/Fluid (Gray): Intermediate density; the heart, muscles, and blood vessels appear in shades of gray. [1, 2]

Common Views

• PA (Posterior-Anterior): The standard view where X-rays enter from the back and exit through the front toward the detector. The patient stands close to the plate, making the heart size and lung structures look sharp and accurate. [1, 2]
• AP (Anterior-To-Posterior): Often used for portable bed-side or ICU exams. The X-ray travels front-to-back, which can make the heart look artificially enlarged. [1, 2, 3]
• Lateral: A side-view taken alongside a PA view to help locate abnormalities in the depth of the chest. [1]

Systematic Interpretation Approach (ABCDE)

Doctors and trainees use a structured framework—such as the ABCDE or ABCDEF method—to avoid missing subtle findings: [1, 2]

• A - Airway: Check the trachea for midline position, narrowing, or deviation, and look at the main bronchi.
• B - Breathing (Lungs & Pleura): Inspect lung zones for opacities, consolidation, or pneumothorax, and check pleural spaces.
• C - Circulation (Heart & Mediastinum): Evaluate the heart size (should be less than 50% of the thoracic width on a PA view) and check mediastinal contours.
• D - Diaphragm: Look at the hemidiaphragm levels and sharp costophrenic angles (blunting can mean fluid/effusion).
• E - Everything Else (Bones & Soft Tissues): Scan the ribs, clavicles, spine, soft tissues, and any visible lines, tubes, or pacemakers. [1, 2, 3, 4]

You can read more detailed breakdown guides via the Radiology Masterclass Tutorial or practice step-by-step reading with Geeky Medics Chest X-Ray Interpretation. [1, 2]