Premium
Effects of diffusion time on short‐range hyperpolarized 3 He diffusivity measurements in emphysema
Author(s) -
Gierada David S.,
Woods Jason C.,
Bierhals Andrew J.,
Bartel Seth T.,
Ritter Jon H.,
Choong Cliff K.,
Das Nitin A.,
Hong Cheng,
Pilgram Thomas K.,
Chang Yulin V.,
Jacob Richard E.,
Hogg James C.,
Battafarano Richard J.,
Cooper Joel D.,
Meyers Bryan F.,
Patterson G. Alexander,
Yablonskiy Dmitriy A.,
Conradi Mark S.
Publication year - 2009
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21912
Subject(s) - effective diffusion coefficient , nuclear medicine , diffusion mri , diffusion , magnetic resonance imaging , nuclear magnetic resonance , medicine , diffusion weighted magnetic resonance imaging , radiology , physics , thermodynamics
Purpose To characterize the effect of diffusion time on short‐range hyperpolarized 3 He magnetic resonance imaging (MRI) diffusion measurements across a wide range of emphysema severity. Materials and Methods 3 He diffusion MRI was performed on 19 lungs or lobes resected from 18 subjects with varying degrees of emphysema using three diffusion times (1.6 msec, 5 msec, and 10 msec) at constant b value. Emphysema severity was quantified as the mean apparent diffusion coefficient (ADC) and as the percentage of pixels with ADC higher than multiple thresholds from 0.30–0.55 cm 2 /sec (ADC index). Quantitative histology (mean linear intercept) was obtained in 10 of the lung specimens from 10 of the subjects. Results The mean ADCs with diffusion times of 1.6, 5.0, and 10.0 msec were 0.46, 0.40, and 0.37 cm 2 /sec, respectively ( P < 0.0001, analysis of variance [ANOVA]). There was no relationship between the ADC magnitude and the effect of diffusion time on ADC values. The mean linear intercept correlated with ADC ( r = 0.91–0.94, P < 0.001) and ADC index ( r = 0.78–0.92, P < 0.01) at all diffusion times. Conclusion Decreases in ADC with longer diffusion time were unrelated to emphysema severity. The strong correlations between the ADC at all diffusion times tested and quantitative histology demonstrate that ADC is a robust measure of emphysema. J. Magn. Reson. Imaging 2009;30:801–808. © 2009 Wiley‐Liss, Inc.