Tiny golden angle stack-of-stars (tygaSoS) free-breathing functional lung imaging

Area of Science:

• Radiology
• Medical Imaging
• Pulmonary Medicine

Background:

• Lung MRI is challenging due to motion and low proton density.
• Functional lung assessment using MRI requires feasible clinical methods.
• Ultra-short echo-time (UTE) imaging offers potential for lung imaging.

Purpose of the Study:

• To evaluate the combination of UTE stack-of-stars (tyGASoS) with tiny golden angle profile ordering.
• To assess its potential for self-gated, free-breathing lung imaging.
• To explore its utility for functional lung assessment.

Main Methods:

• Acquired free-breathing tyGASoS data in 10 healthy volunteers (3 smokers, 7 non-smokers).
• Reconstructed images in different respiratory phases using image-based self-gating.
• Qualitatively assessed image quality and quantitatively measured SNR, proton fraction (fP), and fractional ventilation (FV).

Main Results:

• The imaging protocol was well-tolerated with sufficient image quality and good inter-reader reliability.
• Significant differences in SNR and fP were observed between expiration and inspiration.
• Smokers showed a significantly higher fP compared to non-smokers, indicating potential early smoking-related changes.

Conclusions:

• Free-breathing tyGASoS is feasible for multiphase lung imaging.
• Changes in fP suggest the technique's sensitivity for detecting early responses in smokers.
• Further research is needed to address inter-subject variability in FV quantification.