TY - JOUR
T1 - Hyperpolarized 3He and 129Xe magnetic resonance imaging apparent diffusion coefficients
T2 - Physiological relevance in older never-and ex-smokers
AU - Kirby, Miranda
AU - Ouriadov, Alexei
AU - Svenningsen, Sarah
AU - Owrangi, Amir
AU - Wheatley, Andrew
AU - Etemad-Rezai, Roya
AU - Santyr, Giles E.
AU - McCormack, David G.
AU - Parraga, Grace
N1 - Funding Information:
This study was funded by the Canadian Institutes of Health Research. M. Kirby gratefully acknowledges Ph.D. scholarship support from the Natural Sciences and Engineering Research Council (NSERC, Canada) and G. Parraga gratefully acknowledges support from a Canadian Institutes of Health Research (CIHR) New Investigator Award. Ongoing research funding from CIHR(Canadian Institutes of Health Research) Team Grant CIF#97687 (Thoracic Imaging Network of Canada, TinCAN) is also gratefully acknowledged.
Publisher Copyright:
© 2014 The Authors.
PY - 2014
Y1 - 2014
N2 - Noble gas pulmonary magnetic resonance imaging (MRI) is transitioning away from3He to129Xe gas, but the physiological/clinical relevance of129Xe apparent diffusion coefficient (ADC) parenchyma measurements is not well understood. Therefore, our objective was to generate129Xe MRI ADC for comparison with3He ADC and with well-established measurements of alveolar structure and function in older never-smokers and ex-smokers with chronic obstructive pulmonary disease (COPD). In four never-smokers and 10 COPD ex-smokers,3He (b = 1.6 sec/cm2) and129Xe (b = 12, 20, and 30 sec/ cm2) ADC, computed tomography (CT) density-threshold measurements, and the diffusing capacity for carbon monoxide (DLCO) were measured. To understand regional differences, the anterior-posterior (APG) and superior-inferior (ΔSI) ADC differences were evaluated. Compared to never-smokers, COPD ex-smokers showed greater3He ADC (P = 0.006),129Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.006), but not for ADCb30 (P > 0.05). Never-smokers and COPD ex-smokers had significantly different APG for3He ADC (P = 0.02),129Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.01), but not for ADCb30 (P > 0.05). ΔSI for never-and ex-smokers was significantly different for3He ADC (P = 0.046), but not for129Xe ADC (P > 0.05). There were strong correlations for DLCO with3He ADC and129Xe ADCb12 (both r = −0.95, P < 0.05); in a multivariate model129Xe ADCb12 was the only significant predictor of DLCO (P = 0.049). For COPD ex-smokers, CT relative area <_950 HU (RA950) correlated with3He ADC (r = 0.90, P = 0.008) and129Xe ADCb12 (r = 0.85, P = 0.03). In conclusion, while129Xe ADCb30 may be appropriate for evaluating subclinical or mild emphysema, in this small group of never-smokers and ex-smokers with moderate-to-severe emphysema,129Xe ADCb12 provided a physiologically appropriate estimate of gas exchange abnormalities and alveolar microstructure.
AB - Noble gas pulmonary magnetic resonance imaging (MRI) is transitioning away from3He to129Xe gas, but the physiological/clinical relevance of129Xe apparent diffusion coefficient (ADC) parenchyma measurements is not well understood. Therefore, our objective was to generate129Xe MRI ADC for comparison with3He ADC and with well-established measurements of alveolar structure and function in older never-smokers and ex-smokers with chronic obstructive pulmonary disease (COPD). In four never-smokers and 10 COPD ex-smokers,3He (b = 1.6 sec/cm2) and129Xe (b = 12, 20, and 30 sec/ cm2) ADC, computed tomography (CT) density-threshold measurements, and the diffusing capacity for carbon monoxide (DLCO) were measured. To understand regional differences, the anterior-posterior (APG) and superior-inferior (ΔSI) ADC differences were evaluated. Compared to never-smokers, COPD ex-smokers showed greater3He ADC (P = 0.006),129Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.006), but not for ADCb30 (P > 0.05). Never-smokers and COPD ex-smokers had significantly different APG for3He ADC (P = 0.02),129Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.01), but not for ADCb30 (P > 0.05). ΔSI for never-and ex-smokers was significantly different for3He ADC (P = 0.046), but not for129Xe ADC (P > 0.05). There were strong correlations for DLCO with3He ADC and129Xe ADCb12 (both r = −0.95, P < 0.05); in a multivariate model129Xe ADCb12 was the only significant predictor of DLCO (P = 0.049). For COPD ex-smokers, CT relative area <_950 HU (RA950) correlated with3He ADC (r = 0.90, P = 0.008) and129Xe ADCb12 (r = 0.85, P = 0.03). In conclusion, while129Xe ADCb30 may be appropriate for evaluating subclinical or mild emphysema, in this small group of never-smokers and ex-smokers with moderate-to-severe emphysema,129Xe ADCb12 provided a physiologically appropriate estimate of gas exchange abnormalities and alveolar microstructure.
KW - Apparent diffusion coefficient
KW - COPD
KW - Emphysema
KW - HyperpolarizedHe MRI
KW - HyperpolarizedXe MRI
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U2 - 10.14814/phy2.12068
DO - 10.14814/phy2.12068
M3 - Article
C2 - 25347853
AN - SCOPUS:85002841249
SN - 2051-817X
VL - 2
JO - Physiological Reports
JF - Physiological Reports
IS - 7
M1 - e12068
ER -