Diagnostic accuracy of magnetic resonance imaging for an acute pulmonary embolism: results of the ‘IRM-EP’ study
Article first published online: 2 MAY 2012
© 2012 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 10, Issue 5, pages 743–750, May 2012
How to Cite
REVEL, M. P., SANCHEZ, O., COUCHON, S., PLANQUETTE, B., HERNIGOU, A., NIARRA, R., MEYER, G. and CHATELLIER, G. (2012), Diagnostic accuracy of magnetic resonance imaging for an acute pulmonary embolism: results of the ‘IRM-EP’ study. Journal of Thrombosis and Haemostasis, 10: 743–750. doi: 10.1111/j.1538-7836.2012.04652.x
- Issue published online: 2 MAY 2012
- Article first published online: 2 MAY 2012
- Accepted manuscript online: 9 FEB 2012 02:35PM EST
- Received 24 September 2011, accepted 26 January 2012
- magnetic resonance imaging;
- perfusion imaging;
- pulmonary embolism
Summary. Background: Magnetic resonance imaging (MRI) has not been validated as an alternative diagnostic test to computed tomography angiography (CTA) in patients with suspicion of a pulmonary embolism (PE).
Objectives: To evaluate performance of current MRI technology in diagnosing PE, in reference to a 64-detector CTA.
Patients/methods: Prospective investigation including 300 patients with a suspected PE, referred for CTA after assessment of clinical probability and D-dimer testing. MRI protocol included unenhanced, perfusion and angiographic sequences. MRI results were interpreted by two independent readers, to evaluate inter-reader agreement. Sensitivity and specificity were evaluated globally and according to PE location and to clinical probability category.
Results: Of 300 enrolled patients, 274 were analyzed and 103 (37.5%) had a PE diagnosed by CTA. For patients with conclusive MRI results (72% for reader 1, 70% for reader 2), sensitivity and specificity were 84.5% (95% confidence interval [CI], 74.9–91.4%) and 99.1% (95% CI, 95.1–100.0%), respectively, for reader 1, and 78.7% (95% CI, 68.2–87.1%) and 100% (95% CI, 96.7–100.0%) for reader 2. After exclusion of inconclusive MRI results for both readers, inter-reader agreement was excellent (kappa value: 0.93, 95% CI: 0.88–0.99). Sensitivity was better for proximal (97.7–100%) than for segmental (68.0–91.7%) and sub-segmental (21.4–33.3%) PE (P < 0.0001). Sensitivity was similar for both readers within each clinical probability category.
Conclusions: Current MRI technology demonstrates high specificity and high sensitivity for proximal PE, but still limited sensitivity for distal PE and 30% of inconclusive results. Although a positive result can aid in clinical decision making, MRI cannot be used as a stand-alone test to exclude PE.