From the Research
The sensitivity of a ventilation/perfusion (V/Q) scan for pulmonary embolism (PE) is approximately 85.9% as reported in the most recent and highest quality study 1.
Sensitivity of V/Q Scan for PE
The sensitivity of V/Q scans can vary depending on the specific technique used, with V/Q SPECT showing a higher sensitivity compared to planar V/Q scintigraphy 2.
- The study by 1 found that V/Q SPECT had a sensitivity of 85.9% and a specificity of 93.5% for diagnosing PE.
- In contrast, planar V/Q scintigraphy had a sensitivity of 75.7% and a specificity of 92.9% in the same study 1.
- Another study found that V/Q SPECT had a sensitivity of 100% and a specificity of 87% for diagnosing PE, while planar V/Q scintigraphy had a sensitivity of 64% and a specificity of 72% 2.
Comparison with Other Diagnostic Tests
CT pulmonary angiography (CTPA) is generally considered the gold standard for diagnosing PE, with a higher sensitivity (>90%) compared to V/Q scans 3.
- However, V/Q scans remain a valuable diagnostic tool, particularly for patients with contraindications to CTPA such as renal insufficiency or contrast allergy.
- The study by 3 found that CTA had a sensitivity of 86.0% and a specificity of 93.7%, while V/Q scan had a sensitivity of 96% and a specificity of 97%.
Clinical Application
The sensitivity of V/Q scans can be improved when combined with clinical probability assessment tools like the Wells score or Geneva score 4.
- The study by 5 found that the sensitivity of a high probability V/Q scan was 77.4%, while the specificity of a very low probability or normal V/Q scan was 97.7%.
- The use of V/Q scans in clinical practice should be guided by the individual patient's risk factors and clinical presentation, as well as the availability of other diagnostic tests such as CTPA.