DIAGNOSIS OF PULMONARY-EMBOLISM WITH MAGNETIC-RESONANCE ANGIOGRAPHY

Background Diagnosing pulmonary embolism may be difficult, because the re is no reliable noninvasive imaging method. We compared a new noninv asive method, gadolinium-enhanced pulmonary magnetic resonance angiogr aphy, with standard pulmonary angiography for diagnosing pulmonary emb olism. Methods A total of 30 consecutive patients with suspected pulmo nary embolism underwent both standard pulmonary angiography and magnet ic resonance angiography during the pulmonary arterial phase at the ti me of an intravenous bolus of gadolinium. All magnetic resonance image s were reviewed for the presence or absence of pulmonary emboli by thr ee independent reviewers who were unaware of the findings on standard angiograms. Results Pulmonary embolism was detected by standard pulmon ary angiography in 8 of the 30 patients in whom pulmonary embolism was suspected. All 5 lobar emboli and 16 of 17 segmental emboli identifie d on standard angiograms were also identified on magnetic resonance im ages. Two of the three reviewers reported one false positive magnetic resonance angiogram each. As compared with standard pulmonary angiogra phy, the three sets of readings had sensitivities of 100, 87, and 75 p ercent and specificities of 95, 100, and 95 percent, respectively. The interobserver correlation was good (k=0.57 to 0.83 for all vessels, 0 .49 to 1.0 for main and lobar vessels, and 0.40 to 0.81 for segmental vessels). Conclusions In this preliminary study, gadolinium-enhanced m agnetic resonance angiography of the pulmonary arteries, as compared w ith conventional pulmonary angiography, had high sensitivity and speci ficity for the diagnosis of pulmonary embolism. This new technique sho ws promise as a noninvasive method of diagnosing pulmonary embolism wi thout the need for ionizing radiation or iodinated contrast material. (C) 1997, Massachusetts Medical Society.