2/22/2023 0 Comments Gas inhale mr contrast![]() Intraclass correlation coefficient and Bland-Altman analyses assessed reproducibility of RBC:TP. Friedman tests evaluated the significance of differences in baseline, 6 and 12-month metrics. Spearman’s r determined the strength of correlations. PFTs were performed on the same day as MR. After discarding the first spectrum, spectra were averaged and zeroth-order phased, and integrals over the RBC and TP spectral peaks were evaluated to derive the ratio RBC:TP. Data analysis was performed using MATLAB. A pulse-acquire sequence was used to acquire whole-lung spectra of 129Xe in the TP and RBC compartments (bandwidth: 1.8 kHz flip angle: 90° repetition time: 1 s). Whole lung 129Xe MRS was performed during a 10–15 s breath-hold after inhaling the gas mixture from functional residual capacity. Scans were well tolerated and completed in all, except one participant at the 12-month visit, who completed neither D LCO, nor the MR breath-hold manoeuvre.ġ29Xe was polarised under regulatory licence and 600 mL of isotopically enriched xenon was balanced with nitrogen to a total inhaled dose of 1 L. Each underwent pulmonary MRS with hyperpolarised 129Xe gas on a 1.5T whole-body MRI scanner. Fourteen participants returned at 6 months (195☒4 days) and 13 returned at 12 months (361☓1 days). All underwent baseline imaging and 10 underwent repeated scans 1–3 hours later. During the study, a further three patients commenced pirfenidone and two patients commenced nintedanib. Five patients were taking antifibrotic treatment on recruitment to the study (four on pirfenidone and one on nintedanib). In a study with National Health Service Research Ethics Committee approval, 18 participants with a multidisciplinary diagnosis of IPF were recruited and provided prospective informed written consent. 8 Herein, we describe preliminary findings evaluating the sensitivity of 129Xe MRS to longitudinal physiological changes in patients with IPF. Wang et al recently used 129Xe MRS to identify regions of gas transfer deficit in IPF. 6 7 129Xe shows distinct signals from the red blood cells (RBCs) and interstitial tissue/plasma (TP) compartments by virtue of its environment-dependent resonant frequency, which enables evaluation of gas exchange efficiency by MR spectroscopy (MRS). 5 Of particular interest for pulmonary gas exchange assessment is the solubility of xenon in lung parenchyma and blood. MRI with hyperpolarised helium ( 3He) or xenon ( 129Xe) gas can reveal subtle changes in lung ventilation and microstructure. 3 New biomarkers may help to assess disease progression. 3 An FVC decline of ≥10% is a validated primary endpoint for disease progression and is predictive of mortality, 4 but longitudinal data demonstrate substantial intrapatient variability. Pulmonary function tests (PFTs), including forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (D LCO), form the basis of assessing progression and treatment response, but are insensitive to longitudinal change. Despite significant developments in our understanding of the pathogenesis of idiopathic pulmonary fibrosis (IPF) and the emergence of efficacious treatments, 1 2 prognostication remains challenging.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |