title: 3He MRI-based assessment of posture-dependent regional ventilation gradients in rats.
abstract: A recently developed method for quantitative assessment of regional lung ventilation was employed for the study of posture-dependent ventilation differences in rats. The measurement employed hyperpolarized (3)He MRI to detect the build-up of the signal intensity after increasing numbers of (3)He breaths, which allowed for computation of a regional ventilation parameter. A group of six anesthetized rats was studied in both supine and prone postures. Three-dimensional maps of the ventilation parameter were obtained with high spatial resolution (voxel volume approximately 2 mm(3)). Vertical (dorsal-ventral) gradients of the ventilation index, defined as the regional ventilation normalized by the average ventilation within the whole lung, were investigated. Variations in the regional distribution of the ventilation parameter, as well as of the ventilation index, could be detected, depending on the posture of the rats. In supine posture, ventilation was elevated in the dependent parts of the lungs, with a linear gradient of the ventilation index of -0.11 +/- 0.03 cm(-1). In prone posture, the distribution of ventilation was more uniform, with a significantly (P < 0.001) smaller gradient of the ventilation index of -0.01 +/- 0.02 cm(-1). It is concluded that the (3)He MRI-based method can detect and quantify regional ventilation gradients in animals as small as the rat and that these gradients depend on prone or supine posture of the animal.
authors.affiliation: Dept. of Experimental Research, Malmö Univ. Hospital, SE-205 02 Malmö, Sweden. Sven.Mansson@rontgen.mas.lu.se
authors.forename: Sven
authors.initials: S
authors.lastname: Månsson
authors.forename: Anselm J
authors.initials: AJ
authors.lastname: Deninger
authors.forename: Peter
authors.initials: P
authors.lastname: Magnusson
authors.forename: Göran
authors.initials: G
authors.lastname: Pettersson
authors.forename: Lars E
authors.initials: LE
authors.lastname: Olsson
authors.forename: Georg
authors.initials: G
authors.lastname: Hansson
authors.forename: Per
authors.initials: P
authors.lastname: Wollmer
authors.forename: Klaes
authors.initials: K
authors.lastname: Golman
mesh_terms: D000280:Administration, Inhalation; D000465:Algorithms; D000818:Animals; D003287:Contrast Media; D006371:Helium / Q000008:administration & dosage; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D007554:Isotopes / Q000008:administration & dosage; D008168:Lung / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008571:Men; D011187:Posture / Q000502:physiology*; D016684:Prone Position / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016683:Supine Position / Q000502:physiology
chemical_list: D003287:Contrast Media; D007554:Isotopes; D006371:Helium