title: Evaluation of emphysema severity and progression in a rabbit model: comparison of hyperpolarized 3He and 129Xe diffusion MRI with lung morphometry.
abstract: The apparent diffusion coefficients (ADCs) of hyperpolarized (3)He and (129)Xe gases were measured in the lungs of rabbits with elastase-induced emphysema and correlated against the mean chord length from lung histology. In vivo measurements were performed at baseline and 2, 4, 6, and 8 wk after instillation of elastase (mild and moderate emphysema groups) or saline (control group). ADCs were determined from acquisitions that used two b values. To investigate the effect of b value on the results, b-value pairs of 0 and 1.6 s/cm(2) and 0 and 4.0 s/cm(2) were used for (3)He, and b-value pairs of 0 and 5.0 s/cm(2) and 0 and 10.0 s/cm(2) were used for (129)Xe. At 8 wk after instillation, the rabbits were euthanized, and the lungs were analyzed histologically and morphometrically. ADCs for the rabbits in the control group did not change significantly from baseline to week 8, whereas ADCs for the rabbits in the emphysema groups increased significantly (P < 0.05) for all gas and b-value combinations except (129)Xe with the b-value pair of 0 and 5.0 s/cm(2). The largest percent change in mean ADC from baseline to week 8 (15.3%) occurred with (3)He and the b-value pair of 0 and 1.6 s/cm(2) for rabbits in the moderate emphysema group. ADCs (all b values) were strongly correlated (r = 0.62-0.80, P < 0.001) with mean chord lengths from histology. These results further support the ability of diffusion-weighted MRI with hyperpolarized gases to detect regional and global structural changes of emphysema within the lung.
authors.affiliation: Dept. of Radiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
authors.forename: Jaime F
authors.initials: JF
authors.lastname: Mata
authors.forename: Talissa A
authors.initials: TA
authors.lastname: Altes
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.forename: Kai
authors.initials: K
authors.lastname: Ruppert
authors.forename: Wayne
authors.initials: W
authors.lastname: Mitzner
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Hagspiel
authors.forename: Bina
authors.initials: B
authors.lastname: Patel
authors.forename: Michael
authors.initials: M
authors.lastname: Salerno
authors.forename: James R
authors.initials: JR
authors.lastname: Brookeman
authors.forename: Eduard E
authors.initials: EE
authors.lastname: de Lange
authors.forename: William A
authors.initials: WA
authors.lastname: Tobias
authors.forename: Hsuan-Tsung J
authors.initials: HT
authors.lastname: Wang
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Cates
authors.forename: John P
authors.initials: JP
authors.lastname: Mugler
mesh_terms: D000818:Animals; D001835:Body Weight; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D004646:Emphysema / Q000473:pathology*; D006371:Helium; D007554:Isotopes; D008168:Lung / Q000473:pathology*; D011817:Rabbits; D015203:Reproducibility of Results; D013997:Time Factors; D014979:Xenon Isotopes
chemical_list: D007554:Isotopes; D014979:Xenon Isotopes; D006371:Helium