To determine the diagnostic accuracy of gadolinium enhanced magnetic resonance angiography of the pulmonary arteries (Gd-MRA) in combination with magnetic resonance venography of the veins of the thighs (MRV) in patients with clinically suspected acute pulmonary embolism (PE).

Condition	Intervention
Lung Diseases Pulmonary Embolism	Procedure: magnetic resonance angiography  Procedure: magnetic resonance venography

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

BACKGROUND:

PIOPED III follows PIOPED I and PIOPED II. PIOPED I was a multicenter trial supported between 1983 to 1989 to evaluate the sensitivity and specificity of two major, widely used technologies, radionuclear imaging (ventilation-perfusion scanning) and pulmonary angiography, for the diagnosis of pulmonary embolism. PIOPED II was a multicenter trial conducted between 2000 and 2005 to determine the value of contrast enhanced spiral computed tomography (spiral CT) for the diagnosis of acute pulmonary embolism (PE).

In PIOPED II, among 7889 patients with suspected acute PE, 18.6% had an elevated creatinine, 3.9% were allergic to iodinated contrast material and 4.7% of women were pregnant. One or more of these relative contraindications to an imaging procedure that would expose the patient to ionizing radiation or iodinated contrast material was present in 24.4% of patients with suspected acute PE. Although often patients with relative contraindications take the risk of CT or DSA because of the importance of having a definitive diagnosis, such patients could benefit from safer diagnostic testing with Gd-MRA/MRV if it is shown to be sufficiently accurate.

The purpose of this investigation is to determine the extent to which gadolinium enhanced magnetic resonance angiography (Gd-MRA/MRV) can serve as a diagnostic test in patients with clinically suspected PE, and thereby eliminate the need for iodinated contrast material or ionizing radiation in patients who have a relative contraindication to one of them. This is important because 24% of patients with suspected acute PE have a relative contraindication to diagnostic procedures that involve ionizing radiation or iodinated contrast material.

DESIGN NARRATIVE:

The Prospective Investigation of Pulmonary Embolism Diagnosis III (PIOPED III) is a multicenter prospective investigation designed to determine the diagnostic accuracy of gadolinium enhanced magnetic resonance angiography of the pulmonary arteries (Gd-MRA) in combination with magnetic resonance venography of the veins of the thighs (MRV) in patients with clinically suspected acute pulmonary embolism (PE). The diagnostic accuracy of Gd-MRA alone and in combination with MRV will be expressed as sensitivity, specificity, and likelihood ratio for positive and negative tests. The study design is a prospective study of consecutive patients incorporating standardized inclusion/exclusion criteria, complete ascertainment of patient characteristics and outcomes, uniform diagnostic criteria, and unbiased paired central readings of imaging studies. Over a period of two years, 1256 patients with suspected acute PE will be recruited at clinical centers. Composite reference standards will be used to diagnose VTE and exclude PE. It is expected that 314 patients will have acute VTE and they will undergo Gd-MRA/MRV. It is expected that 942 patients will be shown not to have PE. From among this group, 314 patients will be randomly selected for the index test, Gd-MRA/MRV.

Ages Eligible for Study:  18 Years and above,  Genders Eligible for Study:  Both

Criteria

Included Patients: An estimated 1,256 patients will be recruited among whom 628 will undergo Gd-MRA/MRV. Patients will be 18 years of age or older in whom acute PE is of diagnostic concern, who give informed consent and are willing to undergo Gd-MRA/MRV. Patients must be willing to undergo pulmonary digital subtraction angiography (DSA) if the diagnosis or exclusion of PE is not established by noninvasive means. Occasionally contrast enhanced spiral CT may be used instead of DSA if the patient has not already had a spiral CT.

Excluded Patients: Contraindications for Gd-MRA/MRV include any implanted ferromagnetic foreign body including a ferromagnetic cerebral aneurysm clip or implanted electrical device/pump. Contraindications also include dependency on a continuous connection to an external electrical device/pump (eg. pacemakers internal defibrillators, cochlear implant, nerve or bone stimulator implant, ICU appliance), and cardiac pacing wires. Additional contraindications include severe claustrophobia, severe shaking or the inability to lie still for 30 minutes. Other exclusions include pregnancy; patients with serum creatinine levels >1.5 mg/dl for men or >1.4 mg/dl for women; patients with sickle cell anemia, other hemoglobinopathies, and other hemolytic anemias; patients who are critically ill, currently suffer from shock or hypotension or hemodynamically unstable, on ventilatory support, on chronic anticoagulation, have an inferior vena cava filter, have had documented episodes of ventricular fibrillation or sustained ventricular tachycardia within the past 24 hours, or have experienced a myocardial infarction within the past month, patients who have a history of allergy to gadolinium-containing contrast agents or to iodinated contrast media (because DSA may be required), or history of reactive airway disease, and patients who have clinical evidence of venous thrombosis of the upper extremity will be excluded. Institutionalized individuals or mentally handicapped individuals will be recruited only after informed consent is obtained from the next of kin or legal guardian. Prisoners will be excluded.

Please refer to this study by ClinicalTrials.gov identifier  NCT00241826

Study chairs or principal investigators

Sarah Fowler,  George Washington University   
Charles Hales,  Massachusetts General Hospital   
Russelll Hull,  University of Calgary   
Kenneth Leeper,  Emory University   
David Naidich,  New York University School of Medicine   
Daniel Sak,  St. Joseph Mercy Oakland   
Paul Stein,  St. Joseph Mercy Oakland   
John Weg,  University of Michigan at Ann Arbor   
Pamela Woodard,  Washington University School of Medicine   

Study ID Numbers:  329
Last Updated:  December 9, 2005
Record first received:  October 17, 2005
ClinicalTrials.gov Identifier:  NCT00241826
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2006-01-10