Related Experiment Video
Updated: Feb 7, 2026

Author Spotlight: Standardization and Best Practices for Advancing Lung Imaging Using 129Xe MRI
Published on: November 21, 2023
Effect of T1 relaxation on ventilation mapping using hyperpolarized 129 Xe multiple breath wash-out imaging
Felipe Morgado1,2, Marcus J Couch1,2, Elaine Stirrat1
1Translational Medicine Program, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.
Purpose:
To investigate the effect of incorporating T1 as a function of wash-out breath number (T1 (n)) on estimation of fractional ventilation (r) using hyperpolarized 129 Xe multiple breath wash-out (MBWO) imaging in rats.
Methods:
MBWO imaging was performed in 8 healthy mechanically ventilated rats at several inter-image delay times (τ) and tidal volumes (TV). r maps were calculated from the imaging data using a model of T1 (n) (assuming that the longitudinal relaxation rate of 129 Xe in the lung is directly proportional to pA O2 ) and compared to r maps obtained by assuming a fixed T1 measured before wash-out breaths (r').
Results:
Fractional ventilation was overestimated by up to 19.3% when T1 was fixed. An inverse relationship between bias (Δr) and ventilation was observed at all τ and TV. Additionally, Δr significantly increased when TV was decreased (F statistic F(2,7) = 48.97, P < 10-4 ). Histograms from r' maps were significantly more skewed toward lower values as compared to r histograms at all τ and TV (P < 0.05) except TV = Vdose - 1 mL.
Conclusion:
Analysis of hyperpolarized 129 Xe MBWO imaging using a model incorporating T1 (n) corrects for an overestimating bias in the mapping of fractional ventilation in mechanically ventilated rats introduced by assuming a fixed T1 .
More Related Videos
Related Concept Videos
Breathing
Mechanical Ventilation II: Invasive Ventilation
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation...
Washing, Drying, and Ignition of Precipitates
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....
Classification of Skeletal Muscle Relaxants
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...

