Thrombosis Knowledge Centre
Diagnosis
Diagnosing Pulmonary Embolism
First-line methods
- D-dimers: if normal, rule out PE
- Spiral (or helical) v:
- Captures images of the chest from many angles and, with the aid of a computer, processes these to create cross-sectional pictures or "slices" of the area of interest
- Simultaneously shows many different types of tissue, including the lungs, heart, bones, soft tissues, muscle and blood vessels
- Can directly visualise the thrombus
- Although generally requiring the injection of iodinated contrast products, this technique is usually considered to be "patient-friendly"
- Recommended as the initial imaging technique in suspected non-massive PE
- Ventilation/Perfusion lung scan (or V/Q scan):
- Scintigraphic method showing lung areas ventilated but not perfused with blood in the event of PE
- The results may be:
- Normal: excluding the diagnosis of PE
- Of high probability: confirming the diagnosis of PE
- Or, more frequently, of intermediate or low probability:diagnosis of PE uncertain
- Less often performed because of CT technology, but may be useful in patients with an allergy to iodinated contrast products or renal impairment
- Pulmonary angiography:
- Injection of a radio-contrast agent to reveal the pulmonary arteries
- Gold standard but invasive
- Used if the diagnosis remains uncertain
Other methods
- Venography or ultrasonography for DVT: may be negative if the thrombus has completely embolised
- Chest X-rays: findings non-specific
- Electrocardiogram: findings non-specific (e.g. sinus tachycardia)
- Arterial blood gas measurements: findings non-specifi c (e.g. hypoxia or
- Echocardiogram: in massive PE
- Cardiac biomarkers:
- Troponin: raised levels predict poor outcomes
- Pro-brain natriuretic peptide: raised levels predict poor outcomes
- Magnetic resonance angiography: not currently used in routine practice
Bilateral central PE on CT scan
Goldhaber SZ. Lancet 2004;363:1295-305 and Robinson GV. BMJ 2006;332:156-60
What is the diagnostic strategy for PE?
See below for an example of a diagnostic algorithm for suspected PE
Kyrle and Eichinger. Lancet 2005;365:1163-74