[Helical computed tomography in suspected pulmonary embolism].

Area of Science:

• Radiology and Imaging
• Cardiovascular Medicine
• Pulmonary Medicine

Background:

• Spiral computed tomography (CT) emerged in the early 1990s as a less invasive alternative to pulmonary angiography for diagnosing pulmonary embolism.
• Its widespread adoption preceded a thorough evaluation of its diagnostic accuracy.
• Spiral CT offers greater specificity compared to lung scintigraphy.

Purpose of the Study:

• To evaluate the diagnostic value of spiral computed tomography (CT) in suspected pulmonary embolism.
• To define the criteria for diagnosing and ruling out pulmonary embolism using spiral CT.
• To assess the limitations and appropriate use of spiral CT in clinical algorithms.

Main Methods:

• Review and synthesis of currently available studies on spiral CT for pulmonary embolism diagnosis.
• Analysis of imaging findings, including intraluminal filling defects and perfusion abnormalities.
• Consideration of integration with clinical probability assessment and lower limb venous ultrasonography.

Main Results:

• Visualization of intraluminal filling defects in segmental or more proximal pulmonary arteries is diagnostic of pulmonary embolism.
• Perfusion abnormalities limited to subsegmental or distal arteries are insufficient for diagnosis.
• A 4-8% rate of non-diagnostic tests and the need for iodinated contrast material are key limitations.

Conclusions:

• Spiral CT is diagnostic when significant pulmonary artery filling defects are identified.
• Normal spiral CT findings alone cannot exclude venous thromboembolism and must be combined with other diagnostic tools.
• Spiral CT should be utilized within validated diagnostic algorithms, incorporating clinical assessment and complementary imaging.