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Acute pulmonary embolism: diagnosis with MR angiography
A Gupta1, C K Frazer, J M Ferguson
1Department of Radiology, Sir Charles Gairdner Hospital, Queen Elizabeth II Medical Centre, Nedlands, Western Australia.
Purpose:
To prospectively evaluate pulmonary magnetic (MR) angiography as a diagnostic examination for acute pulmonary embolism (PE).
Materials And Methods:
Thirty-six consecutive patients (19 women, 17 men; age range, 28-84 years) underwent pulmonary digital subtraction angiography (DSA) and pulmonary MR angiography. MR angiograms were obtained during suspended respiration and the pulmonary arterial phase of gadolinium-based contrast medium injection. A steady-state gradient-recalled-echo sequence with free induction decay sampling was used. DSA studies were interpreted for the presence of acute PE by two independent radiologists; an adjudicator made the final decision on discordant interpretations.
Results:
By using DSA, a total of 19 acute pulmonary emboli were depicted in 13 patients. Prospectively, 13 of these emboli were depicted by using MR angiography. MR angiography missed six emboli: Four required the DSA adjudicator to make the decision, and one was in a patient whose MR angiogram was acquired during breathing. Four of these six emboli were small subsegmental emboli, and two were segmental.
Conclusion:
Performed without pulmonary arterial catheterization, iodinated contrast media, or ionizing radiation, pulmonary MR angiography had a high accuracy for depicting lobar and segmental emboli, but was unable to depict four of five subsegmental emboli.
Insights
Pulmonary magnetic resonance (MR) angiography accurately detects large pulmonary emboli (PE) without radiation. However, this imaging technique struggles to identify smaller, subsegmental emboli, necessitating further research for improved diagnostic capabilities.
Area of Science:
- Radiology
- Cardiovascular Imaging
- Pulmonary Medicine
Background:
- Acute pulmonary embolism (PE) is a significant cause of morbidity and mortality.
- Diagnostic imaging plays a crucial role in the timely and accurate diagnosis of PE.
- Pulmonary digital subtraction angiography (DSA) is an invasive gold standard but carries risks.
Purpose of the Study:
- To prospectively assess the diagnostic performance of pulmonary magnetic resonance (MR) angiography for acute PE.
- To compare MR angiography findings with digital subtraction angiography (DSA).
Main Methods:
- Thirty-six patients with suspected PE underwent both pulmonary MR angiography and DSA.
- MR angiography was performed using a steady-state gradient-recalled-echo sequence with gadolinium contrast during breath-hold.
- DSA served as the reference standard, with interpretations by two radiologists and an adjudicator.
Main Results:
- DSA identified 19 pulmonary emboli in 13 patients.
- Pulmonary MR angiography successfully depicted 13 of these emboli.
- Six emboli were missed by MR angiography, including four small subsegmental and two segmental emboli.
Conclusions:
- Pulmonary MR angiography demonstrates high accuracy for lobar and segmental pulmonary emboli.
- The technique is advantageous as it avoids catheterization, iodinated contrast, and ionizing radiation.
- Further refinement is needed to improve the detection of small subsegmental pulmonary emboli.
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