Delayed ventilation assessment using fast dynamic hyperpolarised Xenon-129 magnetic resonance imaging

Abstract

Objectives To investigate the use of a fast dynamic hyperpolarised 129 Xe ventilation magnetic resonance imaging (DXeV-MRI) method for detecting and quantifying delayed ventilation in patients with chronic obstructive pulmonary disease (COPD). Methods Three male participants (age range 31-43) with healthy lungs and 15 patients (M/F = 12:3, age range = 48-73) with COPD (stages II-IV) underwent spirometry tests, quantitative chest computed tomography (QCT), and DXeV-MRI at 1.5-Tesla. Regional delayed ventilation was captured by measuring the temporal signal change in each lung region of interest (ROI) in comparison to that in the trachea. In addition to its qualitative assessment through visual inspection by a clinical radiologist, delayed ventilation was quantitatively captured by calculating a covariance measurement of the lung ROI and trachea signals, and quantified using both the time delay, and the difference between the integrated areas covered by the signal-time curves of the two signals. Results Regional temporal ventilation, consistent with the expected physiological changes across a free breathing cycle, was demonstrated with DXeV-MRI in all patients. Delayed ventilation was observed in 13 of the 15 COPD patients and involved variable lung ROIs. This was in contrast to the control group, where no delayed ventilation was demonstrated (p = 0.0173). Conclusions DXeV-MRI offers a non-invasive way of detecting and quantifying delayed ventilation in patients with COPD, and provides physiological information on regional pulmonary function during a full breathing cycle. Key Points • Dynamic xenon MRI allows for the non-invasive detection and measurement of delayed ventilation in COPD patients. • Dynamic xenon MRI during a free breathing cycle can provide unique information about pulmonary physiology and pulmonary disease pathophysiology. • With further validation, dynamic xenon MRI could offer a non-invasive way of measuring collateral ventilation which can then be used to guide lung volume reduction therapy (LVRT) for certain COPD patients.

Cryptophane–xenon complexes for 129Xe MRI applications

“…Continued research highlighting the use of 129 Xe MRI and cryptophane-based biosensors for the in vivo detection of molecular markers of disease will facilitate the transition to the clinical realm. Based on numerous recent examples of the use of 129 Xe MRI in assessing physiological processes in human lungs and kidneys, [110][111][112][113] we believe that approval for hp 129 Xe to be used in the clinical setting will progressively become increasingly widespread. At the time of this review, the use of hp 129 Xe has not yet attained universal approval for use in general clinical settings, nor have cryptophane-based biosensors been studied in multicellular organisms.…”

Hyperpolarized 129Xe MRI Abnormalities in Dyspneic Patients 3 Months after COVID-19 Pneumonia: Preliminary Results

“…Polarization was measured using a commercial polarisation measurement station (Model 2881, Polarean). Hyperpolarized 129 Xe was thawed into a Tedlar ® bag (Jensen Inert Products, Coral Springs, FL) and given within 10 minutes of production to participants who were lying supine in the MRI scanner ( 12 ).…”

“…Xe gas (86% 129Xe, Spectra Gases Inc.) was polarized as previously described (12). Briefly, 129 Xe gas (86% 129Xe, Spectra Gases Inc., Ely, Cambs) was polarized by rubidium vapour spin exchange optical pumping (SEOP), and cryogenically accumulated in 1-L doses using a commercial polarizer (Model 9810, Polarean, Durham, NC).…”

In vivo methods and applications of xenon-129 magnetic resonance

“…2 a), although greater ventilation abnormalities (and quantitatively higher VDP) are often evident on 129 Xe images when compared to 3 He images [157] , [159] , [163] , [175] , likely due to the lower diffusion coefficient of 129 Xe in air [176] . Similarly, the lower diffusion coefficient of 129 Xe in air limits the sensitivity of time-resolved 129 Xe ventilation imaging for the detection of delayed and collateral ventilation observed in patients with severe COPD using 3 He MRI [177] , [178] . While 1 H anatomical imaging is often performed in a separate breath-hold, advances in multi-nuclear hardware and compressed sensing have made imaging 129 Xe and 1 H within the same breath-hold possible [94] , [136] , [138] .…”