Free-Running Simultaneous Imaging of the Entire Lung and Heart With Isotropic Resolution.

Area of Science:

• Medical Imaging
• Cardiopulmonary Diagnostics
• Magnetic Resonance Imaging

Background:

• Simultaneous imaging of the heart and lungs is crucial for diagnosing cardiopulmonary disorders.
• Current MRI techniques often require breath-holding, limiting scan time and patient compliance.
• Achieving isotropic resolution for both organs remains a challenge.

Purpose of the Study:

• To develop a simultaneous free-breathing MRI technique for the entire lung and heart.
• To achieve isotropic resolution (1.5 mm³) at 1.5T for improved diagnostic capabilities.
• To reduce scan time and minimize patient compliance requirements.

Main Methods:

• A 3D radial dual-echo balanced steady-state free precession (bSSFP) sequence was developed for free-running acquisition.
• Respiratory and cardiac motion states were estimated using superior-inferior navigators and data binning.
• A subspace-based motion-compensation algorithm reconstructed five-dimensional (5D) cardiopulmonary images.

Main Results:

• The dual-echo bSSFP sequence provided superior myocardium-blood contrast over GRE-UTE.
• Simultaneous dynamic 5D images of the entire lungs and heart were successfully acquired.
• 5D imaging demonstrated clearer depiction of cardiac and adjacent pulmonary structures compared to 4D imaging.

Conclusions:

• A novel simultaneous cardiopulmonary MRI technique enables 5D dynamic imaging with isotropic resolution.
• The technique allows for high-resolution imaging of the entire cardiopulmonary system in a single, free-breathing scan (~10 min).
• This method holds significant potential for comprehensive structural and functional assessment of the cardiopulmonary system.