Efficacy of thrombolytic therapy in pulmonary embolism determined by MION-enhanced MRA: an experimental study in rabbits.

Abstract

RATIONALE AND OBJECTIVES:

This study determined whether contrast-enhanced magnetic resonance angiography could be used as a noninvasive imaging technique to determine the therapeutic effect and endpoint in thrombolysis of acute pulmonary embolism in an animal model.

METHODS:

New Zealand white rabbits (n = 18) were anesthetized and mechanically ventilated. Single (n = 12 emboli) or dual (n = 12 emboli in 6 animals) pulmonary emboli were created by injecting autologous thrombi through a right internal jugular venous approach. Three-dimensional time of flight (TOF) magnetic resonance angiograms were obtained after intravenous administration of 2 mg Fe of a long circulating monocrystalline iron oxide. Animals then received 5000 IU heparin and 1.3 mg recombinant tissue plasminogen activator/kg intravenously, and magnetic resonance angiography was repeated 30 minutes and 60 minutes after initiation of thrombolytic therapy.

RESULTS:

MION-enhanced magnetic resonance angiography accurately detected pulmonary emboli in all rabbits. Thrombolysis during the observation period was successful in 8 of the 18 animals. In animals with a single embolus, the revascularization rate was 50% (6 of 12 emboli). The rate was 33% (4 of 12 emboli) in animals with multiple emboli. Magnetic resonance angiography allowed determination of thrombus resolution or thrombus persistence.

CONCLUSIONS:

It was feasible to diagnose pulmonary embolism accurately in this experimental study and to monitor thrombolysis of pulmonary emboli by MION-enhanced magnetic resonance angiography.

• Authors: H Frank, R Loewe, C Loewe, G Oberhuber, B Schwaighofer, K Huber, R Weissleder
• Journal: Investigative radiology (Invest Radiol) Vol. 33 Issue 12 Pg. 853-7 (Dec 1998) ISSN: 0020-9996 [Print] United States
• PMID: 9851818 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Contrast Media
• Fibrinolytic Agents
• Oxides
• Plasminogen Activator Inhibitor 1
• Recombinant Proteins
• Heparin
• Iron
• Tissue Plasminogen Activator
• Ferrosoferric Oxide

Topics

• Acute Disease
• Animals
• Contrast Media
• Disease Models, Animal
• Drug Evaluation, Preclinical
• Ferrosoferric Oxide
• Fibrinolytic Agents (therapeutic use)
• Heparin (therapeutic use)
• Iron
• Magnetic Resonance Angiography (instrumentation, methods)
• Oxides
• Plasminogen Activator Inhibitor 1 (blood)
• Pulmonary Embolism (blood, diagnosis, drug therapy)
• Rabbits
• Recombinant Proteins (therapeutic use)
• Retrospective Studies
• Thrombolytic Therapy
• Time Factors
• Tissue Plasminogen Activator (blood, drug effects, therapeutic use)