60 year old gentleman with a 1-day history of left-sided pleuritic chest pain. Abdominal surgery 5 weeks prior and subsequent decreased mobility.

Attended the emergency department (ED) and was treated expectantly with therapeutic enoxaparin and managed on an ambulatory pathway for suspected pulmonary embolism (PE).

While plain radiography is by no means considered the gold standard in the diagnosis of PE, there are a number of will recognized plain radiographic signs that have been described:

• Hampton hump - peripheral, wedge-shaped air space opacity usually in the lower zones. To be more precise, Hampton hump implies pulmonary infarct rather than pulmonary embolism. 
• Westermark sign - regional oligemia in the pulmonary segment supplied by the affected PE. 
• Fleischner sign - Enlarged pulmonary artery. Can be seen in PE and pulmonary hypertension.

The sensitivity and specificity of these signs are not great enough to allow confident diagnosis, however, and in the appropriate clinical setting, further investigation CT pulmonary angiogram (CTPA) or ventilation-perfusion (V/Q scan) is warranted.