Magnetic Resonance Diagnosis of Pulmonary Embolism

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the diagnostic accuracy of thoracic magnetic resonance imaging with gadolinium-enhanced, unenhanced and perfusion sequences in patients with clinically suspected acute pulmonary embolism Thoracic CT angiography (CTA) will serve as reference standard Result of MRI will not interfere with patients' management Untreated patients with negative CTA will have 3-month follow-up to verify they were free of thrombose-embolic disease

Detailed Description
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Background In patients with clinically suspected pulmonary embolism (PE)°with a contraindication to thoracic CT angiography, there is a need for an alternative diagnostic procedure. MRI has not been fully evaluated in this field; moreover, recent technological advances make it necessary to re-evaluate its performance for PE diagnosis. Design Prospective monocentric study Patients with clinically suspected acute pulmonary embolism will undergo thoracic magnetic resonance imaging if inclusion criteria are fulfilled. A non-inclusion register will be establish for patients fulfilling the inclusion criteria , not included because MRI was not available (off-hours presentation , another patients already included in the protocol on the same day ) Estimated enrolment : 280 (based on a 25% prevalence of PE in our institution and an expected 80% sensitivity of MRI) Study start date: June 2007 Estimated study completion date: 17 months later (40 to 50 presentations for PE suspicion each month, 20 inclusions expected per month) Magnetic Resonance imaging: performed on a 1.5 Tesla unit with 3 different sequences Unenhanced Steady State Free Precession (SSFP) sequences Perfusion imaging following Gadolinium injection at a rate of 5 c/s and a dose of 0.1mmol/kg Magnetic resonance angiography following an injection of 0.1mmol/kg of gadolinium at 3ml/s MRI studies will be interpreted secondarily by 2 independent radiologists, blinded to CTA results and clinical probability. Two different readings will be performed, one global reading and one reading of each sequence separately, displayed in a random order (access base) Objectives to evaluate MRI performance for PE diagnosis globally to evaluate the diagnostic value for each sequence (especially the negative predictive value of a normal perfusion sequence) to evaluate inter-observer agreement MRI and CTA have to be performed within 24 hours

Official Title
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Magnetic Resonance Diagnosis of Pulmonary Embolism: Prospective Evaluation in 280 Patients, With Comparison to Multi-slice CT Angiography

Conditions
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Lung Diseases, Pulmonary Embolism

Intervention / Treatment
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* Procedure: Gadolinium-enhanced Magnetic Resonance Imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinically suspected acute pulmonary embolism 18 years old or more D-dimers more than 500 or high clinical probability of pulmonary embolism according to the revised Geneva score Thoracic CT angiography performed within 24 hours Informed consent Exclusion Criteria: - Contraindication to MRI (pace maker, claustrophobia, any implanted ferromagnetic foreign body) Obese patients too large to fit in MRI unit Allergy to gadolinium-containing contrast agent or to iodinated contrast media Renal insufficiency (clearance less than 30 ml/mn) Anticoagulation at a curative dose started more than 48 hours prior to MRI Life expectancy less than 3 months Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Gadolinium-enhanced Magnetic Resonance Imaging|Gadolinium-enhanced Magnetic Resonance Imaging|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MRI studies will be interpreted at the end of the inclusion process. CTA results will serve as reference standard to evaluate MRI sensitivity, specificity, positive and negative predictive values. Inter-observer agreement will be evaluated |  | 17 months after the first inclusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 3 months clinical follow-up will be performed in patients with negative CTA results who did not receive anticoagulation. This is to verify there were no false negatives on CTA |  | 3 months afer CTA | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Magnetic Resonance Imaging/methods, Magnetic Resonance Angiography, Perfusion Imaging, Pulmonary Embolism/diagnosis