Time-series hyperpolarized xenon-129 MRI of lobar lung ventilation of COPD in comparison to V/Q-SPECT/CT and CT

Abstract

Purpose To derive lobar ventilation in patients with chronic obstructive pulmonary disease (COPD) using a rapid time-series hyperpolarized xenon-129 (HPX) magnetic resonance imaging (MRI) technique and compare this to ventilation/perfusion single-photon emission computed tomography (V/Q-SPECT), correlating the results with high-resolution computed tomography (CT) and pulmonary function tests (PFTs). Materials and methods Twelve COPD subjects (GOLD stages I–IV) participated in this study and underwent HPX-MRI, V/Q-SPECT/CT, high-resolution CT, and PFTs. HPX-MRI was performed using a novel time-series spiral k-space sampling approach. Relative percentage ventilations were calculated for individual lobe for comparison to the relative SPECT lobar ventilation and perfusion. The absolute HPX-MRI percentage ventilation in each lobe was compared to the absolute CT percentage emphysema score calculated using a signal threshold method. Pearson’s correlation and linear regression tests were performed to compare each imaging modality. Results Strong correlations were found between the relative lobar percentage ventilation with HPX-MRI and percentage ventilation SPECT ( r = 0.644; p < 0.001) and percentage perfusion SPECT ( r = 0.767; p < 0.001). The absolute CT percentage emphysema and HPX percentage ventilation correlation was also statistically significant ( r = 0.695, p < 0.001). The whole lung HPX percentage ventilation correlated with the PFT measurements (FEV 1 with r = − 0.886, p < 0.001*, and FEV 1 /FVC with r = − 0.861, p < 0.001*) better than the whole lung CT percentage emphysema score (FEV 1 with r = − 0.635, p = 0.027; and FEV 1 /FVC with r = − 0.652, p = 0.021). Conclusion Lobar ventilation with HPX-MRI showed a strong correlation with lobar ventilation and perfusion measurements derived from SPECT/CT, and is better than the emphysema score obtained with high-resolution CT. Key Points • The ventilation hyperpolarized xenon-129 MRI correlates well with ventilation and perfusion with SPECT/CT with the advantage of higher temporal and spatial resolution. • The hyperpolarized xenon-129 MRI correlates with the PFT measurements better than the high-resolution CT with the advantage of avoiding the use of ionizing radiation. Electronic supplementary material The online version of this article (10.1007/s00330-018-5888-y) contains supplementary material,...

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

“…In this study, adjustment for the variation in the local oxygen concentration was not included in the analysis. T1 may vary between 26 to 33 seconds between different ROIs of the same participant, as we discussed in our previous work [28]. Considering the time delay was calculated over a time period of around 10 seconds, this T1 variation might result in up to 10% variation in signal-time product difference and/or time delay.…”

“…Both gases, at the imaging doses prescribed, are well-tolerated by both healthy individuals and patients with lung diseases [23][24][25]. More recently, hyperpolarised 129 Xe has been shown to be a promising tool for measuring lobar ventilation [26,27], and for identifying temporal changes in the arrival of xenon gas to different parts of the lung [28,29].…”

High Resolution3He Pulmonary MRI

“…Exploiting these signals for diagnostic imaging purposes can be difficult since for example, only about 2% of inhaled xenon dissolves into the tissue barrier and RBC [76,79], and the corresponding T 2 * values are often short ($2 ms) [80]. There is an urgent need for efficient short-TE methods to acquire these short T 2 * signals and enable deeper study of a number of lung abnormalities such as ventilation/perfusion mismatch [81,82] and of other organs including xenon brain perfusion imaging [72,83] and imaging of the xenon-encapsulated Cryptophane-A functionalized with anti-cancer drugs [84].…”

<p>Quantitative Emphysema Measurement On Ultra-High-Resolution CT Scans</p>

“…[1][2][3][4][5][6][7][8][9][10][11] The percentage of low attenuation areas/volumes for the total lung areas/volumes on thin-section CT scans are widely known to be significantly correlated with the results of various pulmonary function tests, including spirometry and diffusing capacity of the lungs for carbon monoxide. [4][5][6] Although current quantitative emphysema measurements can be automatically performed by commercially available workstations and open-access software, the measurements are affected by several scanning/reconstruction parameters and other factors, including section thickness, reconstruction kernels, radiation dose settings, iterative reconstruction techniques, and brand of scanner. [4][5][6][7][8][9]12,13 It has been reported that the extent of emphysema tends to increase with thinner sections and sharper reconstruction kernels.…”

“…[4][5][6] Although current quantitative emphysema measurements can be automatically performed by commercially available workstations and open-access software, the measurements are affected by several scanning/reconstruction parameters and other factors, including section thickness, reconstruction kernels, radiation dose settings, iterative reconstruction techniques, and brand of scanner. [4][5][6][7][8][9]12,13 It has been reported that the extent of emphysema tends to increase with thinner sections and sharper reconstruction kernels. 9 Furthermore, compared with conventional filtered-back-projection (FBP) methods, an iterative reconstruction (IR) algorithm can stabilize emphysema measurements with low-dose settings, and reduce radiation exposure without compromising image quality.…”