Abstract
Background: Hyperpolarized 129Xe magnetic resonance imaging(HP-MRI) is a novel technique shown to be useful in evaluating obstructive lung diseases(OLD). HP-MRI requires inhalation of a non-radioactive gas for calculating ventilatory defect percentage(VDP). In healthy adults, VDP is inversely related to lung inflation state(LIS) at time of imaging but this has not been studied in children or participants with OLD.
Aim: To investigate how LIS affects VDP in participants with airway obstruction(AO).
Methods: HP-MRI was conducted in a 31-year-old with moderate obstruction (FEV1pred of 65%, FEV1/FVC of 66%). Imaging was performed on a 3T MR system (Siemens Healthcare, Erlangen, Germany) and HP-MRI scans using a flexible vest coil (Clinical MR Solutions, WI, U.S.A.). Images were acquired over a 10-16 second breath-hold at 4 inflation states: residual volume(RV)+1/6 of total lung capacity(TLC), RV+1L, functional residual capacity(FRC)+1/6 of TLC, FRC+1L.
Results: Figure 1A shows representative HP-MRI images with ventilation defects. Figure 1B shows VDP is greatest at RV+1/6 of TLC and inversely related with lung volume.
Conclusions: This is the first of an ongoing study to assess the effect of LIS on VDP in patients with AO. In this participant, the VDP is largest at low LIS (RV+1/6 of TLC) likely due to air trapping. This underlines the importance of LIS standardization in HP-MRI to ensure accuracy of VDP measurements.
Footnotes
Cite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2088.
This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2020
