The Normal Chest X-Ray

The CXR on the next slide is normal. How would you interpret it? Introduction Most of the chest x-rays you will see will be normal In order to recognise abnormality, you need to know what a normal CXR looks like The CXR on the next slide is normal. How would you interpret it?

General Principles Have a systematic approach Interpret the CXR in conjunction with the clinical findings Always compare with previous CXR if available to assess for change Ask yourself “does my interpretation make sense?”

Systematic Approach Name/marker/rotation/ penetration Lines/metal work Heart Mediastinum Lungs Zones (upper/middle/lower) Bones Diaphragm Soft Tissues

Systematic Approach Name/marker/rotation/ penetration clavicles equidistant from spinous processes of thoracic spine can just see lower thoracic spine

Systematic Approach Lines/metal work Look for: Sternal wires (implies previous thoracic surgery) Tip of endotracheal tube (2cm above carina)

Systematic Approach Lines/metal work Tip of central venous lines at origin of superior vena cava. See tubes and lines presentation.

Systematic Approach Heart Occupies up to 50% of the maximum internal thoracic diameter on a standard PA erect view Cannot comment on heart size on AP view because of magnification of heart

Systematic Approach Mediastinum Hilar vascular structures should be crisply defined No widening of mediastinum Trachea should be central

Systematic Approach Lungs Compare upper, mid and lower zones upper zone Compare upper, mid and lower zones Look between ribs for lung detail Remember to look “behind” the heart middle zone lower zone

Systematic Approach Bones Look at each rib in turn Clavicles Scapulae and humeri if visible Lower cervical and thoracic spine

Systematic Approach Diaphragm Both diaphragms should form a sharp margin with the lateral chest wall Both diaphragm contours should be clearly visible medially to the spine Position of stomach gas bubble (not present on this CXR)

Systematic Approach Soft Tissues Supraclavicular fossae (enlarged nodes) Lateral chest wall (surgical emphysema) Under diaphragm (pneumoperitoneum)

How would you summarise this?

“This is an erect chest X-Ray of an adult male “This is an erect chest X-Ray of an adult male. The heart is not enlarged, the mediastinal contours are normal and the lungs are clear”

Take Home Points Be systematic Review with history and physical examination in mind