Feasibility of detecting pulmonary embolism using noncontrast MRI

Area of Science:

• Cardiovascular Imaging
• Pulmonary Medicine
• Radiology

Background:

• Pulmonary embolism (PE) is a significant cause of morbidity and mortality.
• Accurate detection of PE is crucial for timely treatment.
• Computed tomography pulmonary angiography (CTPA) is the standard diagnostic tool, but involves ionizing radiation and contrast agents.

Purpose of the Study:

• To assess the feasibility of detecting pulmonary emboli using noncontrast magnetic resonance imaging (MRI).
• To evaluate the diagnostic performance of noncontrast MRI compared to CTPA in patients with known PE.

Main Methods:

• Eleven patients with acute PE diagnosed by CTPA underwent cardiac MRI.
• The precontrast portion of the MRI was reviewed by two independent observers for the presence of PE.
• Vessels were scored as positive or negative for PE, mirroring the CTPA interpretation.

Main Results:

• MRI was performed approximately 40 hours after CTPA.
• 69% of pulmonary emboli identified on CTPA were detected on noncontrast MRI.
• All large emboli in the right or left pulmonary arteries were identified by MRI, while smaller, subsegmental emboli were often missed.

Conclusions:

• Noncontrast MRI is a feasible method for detecting pulmonary emboli, particularly larger ones in central pulmonary arteries.
• Despite limitations in protocol optimization for pulmonary artery visualization, MRI showed promising results in identifying PE.
• Further research could explore optimized MRI protocols to improve sensitivity for smaller emboli.