Abstract
Overview
Hyperpolarized (HP) gas MRI can be combined with spatially registered proton (1H) images of the lung to calculate percentage lung ventilation (PV). However, any lung inflation difference between separate 1H and 3He breath-holds results in errors.
Aim
To increase PV accuracy using a novel single breath-hold 3He and 1H acquisition.
Methods
10 asthma patients were scanned with 3He MRI. The protocol was repeated at baseline to assess short-term reproducibility. Patients inhaled 1L (35% 3He/65% N2) from FRC. Immediately following this (in the same breath-hold) 1H MRI was acquired. A separate breath-hold set of 1H images were also acquired at FRC+1L.
Ventilated volume (vV), lung volume (LV) and PV(vV/LV) were calculated. PVSingle used 3He and 1H images from the same breath hold. PVSeparate used 1H images from the separate breath hold.
Results
Figure 1 shows how lung inflation variation between separate breath-hold 3He (a) and 1H (b) MRI affects PV (c). Acquisition of 3He and 1H MRI during single breath-hold (a,d) gave a more accurate PV measurement (e).
Mean baseline difference was 2.19±10.1% for PVSingle and 9.79±22.5% for PVSeparate, a significant difference (p<0.04).
Conclusion
Percentage lung ventilation measurements using single breath-hold 3He and 1H acquisition were more reproducible than measurements using separate breathold 3He and 1H images.
Funding
AIRPROM FP7 and Novartis.
- © 2013 ERS