Accelerated fractional ventilation imaging with hyperpolarized Gas MRI

Area of Science:

• Medical Imaging
• Pulmonary Medicine
• Biophysics

Background:

• Hyperpolarized gas MRI is crucial for assessing lung ventilation.
• Current methods face limitations due to breath-hold duration and signal decay.
• Improving measurement accuracy is vital for clinical applications.

Purpose of the Study:

• To evaluate accelerated imaging for enhanced accuracy in fractional ventilation (r) measurement using hyperpolarized gas MRI.
• To investigate the impact of undersampling on breath-hold time and signal decay.
• To assess the effect of acceleration on radiofrequency-induced gas destruction.

Main Methods:

• Image acceleration was implemented using an eight-channel phased array coil.
• Undersampled data acquisition was simulated and reconstructed for various matrix sizes.
• Accelerated imaging was performed in vivo on five mechanically ventilated pigs.

Main Results:

• An optimal acceleration factor of approximately 2x was identified, independent of resolution.
• Estimation accuracy improved significantly with higher resolutions, showing 39-51% error reduction.
• In vivo r values showed no significant difference between standard and accelerated methods, but vertical gradients differed significantly.

Conclusions:

• Undersampled image acceleration is a viable strategy to improve fractional ventilation measurement accuracy.
• The findings support the use of accelerated hyperpolarized gas MRI for more precise lung ventilation assessment.
• This technique offers potential for reduced breath-hold times and improved physiological relevance.