DRSABCDE of CXR Interpretation

Before you even begin interpreting a CXR you should have the correct details. This includes;

• Patient name, age / DOB, sex
• Type of film – PA or AP, erect or supine, correct L/R marker, inspiratory/expiratory series
• Date and time of study

Next up, how “ripe” is the image. That is, what is the technical quality of the film?

• Rotation – medial clavicle ends equidistant from spinous process
• Inspiration – 5-6 anterior ribs in MCL or 8-10 posterior ribs above diaphragm, poor inspiration?, hyperexpanded?
• Picture – straight vs oblique, entire lung fields, scapulae outside lung fields, angulation (ie ’tilt’ in vertical plane)
• Exposure (Penetration) – IV disc spaces, spinous processes to ~T4, L) hemidiaphragm visible through cardiac shadow.

In CXR interpretation it is common to leave soft tissues until the end.

• Ribs, sternum, spine, clavicles – symmetry, fractures, dislocations, lytic lesions, density
• Soft tissues – looking for symmetry, swelling, loss of tissue planes, subcutaneous air, masses
• Breast shadows
• Calcification – great vessels, carotids

• Trachea – central or slightly to right lung as crosses aortic arch
• Paratracheal/mediastinal masses or adenopathy
• Carina & RMB/LMB
• Mediastinal width <8cm on PA film
• Aortic knob
• Hilum – T6-7 IV disc level, left hilum is usually higher (2cm) and squarer than the V-shaped right hilum.
• Check vessels, calcification.

Lung Fields:

• Vascularity – to ~2cm of pleural surface (~3cm in apices), vessels in bases > apices
• Pneumothorax – don’t forget apices
• Lung field outlines – abnormal opacity/lucency, atelectasis, collapse, consolidation, bullae
• Horizontal fissure on Right Lung
• Pulmonary infiltrates – interstitial vs alveolar pattern
• Coin lesions
• Cavitary lesions

Pleura

• Pleural reflections
• Pleural thickening

• Heart position –⅔ to left, ⅓ to right
• Heart size – measure cardiothoracic ratio on PA film (normal <0.5)
• Heart borders – R) border is R) atrium, L) border is L) ventricle & atrium
• Heart shape
• Aortic stripe

• Hemidiaphragm levels – Right Lung higher than Left Lung (~2.5cm / 1 intercostal space)
• Diaphragm shape/contour
• Cardiophrenic and costophrenic angles – clear and sharp
• Gastric bubble / colonic air
• Subdiaphragmatic air (pneumoperitoneum)

• ETT, CVP line, NG tube, PA catheters
• ECG electrodes, PICC line, chest tube
• PPM, AIDC, metalwork