Diagnostic accuracy of magnetic resonance imaging for acute pulmonary embolism: results of the "IRM-EP" study.
J Thromb Haemost. 2012 Feb 9;
Authors: Revel MP, Sanchez O, Couchon S, Planquette B, Hernigou A, Niarra R, Meyer G, Chatellier G
Abstract
Background: Magnetic resonance imaging (MRI) has not been validated as an alternative diagnostic test to CT angiography (CTA) in patients with pulmonary embolism (PE) suspicion. Objectives: To evaluate performance of current MRI technology in diagnosing PE, in reference to 64-detector CTA. Patients/Methods: Prospective investigation including 300 patients with 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 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% 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 comparable 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.
PMID: 22321816 [PubMed - as supplied by publisher]