David G Mummy1,2, Erika M Coleman3, Ziyi Wang4, Elianna A Bier4, Junlan Lu5, Bastiaan Driehuys1,2,4,5, Yuh-Chin Huang3. 1. Center for In Vivo Microscopy, Duke University, Durham, North Carolina, USA. 2. Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA. 3. Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA. 4. Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA. 5. Department of Medical Physics, Duke University, Durham, North Carolina, USA.
Abstract
BACKGROUND: Hyperpolarized 129 Xe magnetic resonance imaging (MRI) provides a non-invasive assessment of regional pulmonary gas exchange function. This technique has demonstrated that chronic obstructive pulmonary disease (COPD) patients exhibit ventilation defects, reduced interstitial barrier tissue uptake, and poor transfer to capillary red blood cells (RBCs). However, the behavior of these measurements following therapeutic intervention is unknown. PURPOSE: To characterize changes in 129 Xe gas transfer function following administration of an inhaled long-acting beta-agonist/long-acting muscarinic receptor antagonist (LABA/LAMA) bronchodilator. STUDY TYPE: Prospective. POPULATION: Seventeen COPD subjects (GOLD II/III classification per Global Initiative for Chronic Obstructive Lung Disease criteria) were imaged before and after 2 weeks of LABA/LAMA therapy. FIELD STRENGTH/SEQUENCES: Dedicated ventilation imaging used a multi-slice 2D gradient echo sequence. Three-dimensional images of ventilation, barrier uptake, and RBC transfer used an interleaved, radial, 1-point Dixon sequence. Imaging was acquired at 3 T. ASSESSMENT: 129 Xe measurements were quantified before and after LABA/LAMA treatment by ventilation defect + low percent (vendef + low ) and by barrier uptake and RBC transfer relative to a healthy reference population (bar%ref and RBC%ref ). Pulmonary function tests, including diffusing capacity of the lung for carbon monoxide (DLCO ), were also performed before and after treatment. STATISTICAL TESTS: Paired t-test, Pearson correlation coefficient (r). RESULTS: Baseline vendef + low was 57.8 ± 8.4%, bar%ref was 73.2 ± 19.6%, and RBC%ref was 36.5 ± 13.6%. Following treatment, vendef + low decreased to 52.5 ± 10.6% (P < 0.05), and improved in 14/17 (82.4%) of subjects. However, RBC%ref decreased in 10/17 (58.8%) of subjects. Baseline measurements of bar%ref and DLCO were correlated with the degree of post-treatment change in vendef + low (r = -0.49, P < 0.05 and r = -0.52, P < 0.05, respectively). CONCLUSION: LABA/LAMA therapy tended to preferentially improve ventilation in subjects whose 129 Xe barrier uptake and DLCO were relatively preserved. However, newly ventilated regions often revealed RBC transfer defects, an aspect of lung function opaque to spirometry. These microvasculature abnormalities must be accounted for when assessing the effects of LABA/LAMA therapy. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 4.
BACKGROUND: Hyperpolarized 129 Xe magnetic resonance imaging (MRI) provides a non-invasive assessment of regional pulmonary gas exchange function. This technique has demonstrated that chronic obstructive pulmonary disease (COPD) patients exhibit ventilation defects, reduced interstitial barrier tissue uptake, and poor transfer to capillary red blood cells (RBCs). However, the behavior of these measurements following therapeutic intervention is unknown. PURPOSE: To characterize changes in 129 Xe gas transfer function following administration of an inhaled long-acting beta-agonist/long-acting muscarinic receptor antagonist (LABA/LAMA) bronchodilator. STUDY TYPE: Prospective. POPULATION: Seventeen COPD subjects (GOLD II/III classification per Global Initiative for Chronic Obstructive Lung Disease criteria) were imaged before and after 2 weeks of LABA/LAMA therapy. FIELD STRENGTH/SEQUENCES: Dedicated ventilation imaging used a multi-slice 2D gradient echo sequence. Three-dimensional images of ventilation, barrier uptake, and RBC transfer used an interleaved, radial, 1-point Dixon sequence. Imaging was acquired at 3 T. ASSESSMENT: 129 Xe measurements were quantified before and after LABA/LAMA treatment by ventilation defect + low percent (vendef + low ) and by barrier uptake and RBC transfer relative to a healthy reference population (bar%ref and RBC%ref ). Pulmonary function tests, including diffusing capacity of the lung for carbon monoxide (DLCO ), were also performed before and after treatment. STATISTICAL TESTS: Paired t-test, Pearson correlation coefficient (r). RESULTS: Baseline vendef + low was 57.8 ± 8.4%, bar%ref was 73.2 ± 19.6%, and RBC%ref was 36.5 ± 13.6%. Following treatment, vendef + low decreased to 52.5 ± 10.6% (P < 0.05), and improved in 14/17 (82.4%) of subjects. However, RBC%ref decreased in 10/17 (58.8%) of subjects. Baseline measurements of bar%ref and DLCO were correlated with the degree of post-treatment change in vendef + low (r = -0.49, P < 0.05 and r = -0.52, P < 0.05, respectively). CONCLUSION:LABA/LAMA therapy tended to preferentially improve ventilation in subjects whose 129 Xe barrier uptake and DLCO were relatively preserved. However, newly ventilated regions often revealed RBC transfer defects, an aspect of lung function opaque to spirometry. These microvasculature abnormalities must be accounted for when assessing the effects of LABA/LAMA therapy. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 4.
Authors: Tahmina Achekzai; Kai Ruppert; Luis Loza; Faraz Amzajerdian; Harrilla Profka; Ian F Duncan; Stephen J Kadlecek; Rahim R Rizi Journal: Magn Reson Med Date: 2022-08-31 Impact factor: 3.737
Authors: Dave Singh; Jim M Wild; Dinesh Saralaya; Rod Lawson; Helen Marshall; Jonathan Goldin; Matthew S Brown; Konstantinos Kostikas; Kristin Belmore; Robert Fogel; Francesco Patalano; Anton Drollmann; Surendra Machineni; Ieuan Jones; Denise Yates; Hanns-Christian Tillmann Journal: Respir Res Date: 2022-02-10