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 - 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 -