Clinical use of oxygen-enhanced T₁ mapping MRI of the lung: Reproducibility and impact of closed versus loose fit oxygen delivery system

Materials and Methods: Twelve healthy volunteers were examined on two visits with an inversion recovery snapshot fast low angle shot sequence on a 1.5 T system. Coronal slices were obtained breathing room air as well as 100% oxygen with a flow rate of 15 L/min. For oxygen delivery a standard nontight face mask and a full closed air-cushion face mask were used. T₁ relaxation times and the oxygen transfer function (OTF) were calculated.

Results: The mean T₁ values did not change significantly between the two visits (P>0.05). The T₁ values breathing 100% oxygen obtained using the full closed mask were significantly lower (1093±38 msec; P<0.05) compared to the standard mask (1157±52 msec). Accordingly, the OTF was significantly higher for the full closed mask (P<0.05). The OTF changed significantly on the second visit using the standard mask (P<0.05). The full closed mask showed lower interindividual variation for both the T₁ values (3.5% vs. 4.5%) as well as the OTF (12.4% vs. 22.0%) and no difference of the OTF on the second visit (P>0.05).

Conclusion: Oxygen-enhanced T₁ mapping MRI produces reproducible data when using a full closed face mask.

Purpose: To evaluate the reproducibility of oxygenenhanced magnetic resonance imaging (MRI), and the influence of different gas delivery methods, in a clinical environment.