title: Measurement of MR signal and T2* in lung to characterize a tight skin mouse model of emphysema using single-point imaging.
abstract: OBJECTIVE
  To evaluate whether MRI signal and T2* measurements of lung tissue acquired at ultrashort detection times (tds) can detect emphysematous changes in lungs.
  
  
  METHODS
  MR signal intensity of in vivo mouse lungs was measured at 4.7 T at tds of 0.2 and 0.4 msec using single-point imaging (SPI). T2* was calculated from the measurements obtained at the two tds. Two groups of 8- and 30-week-old Tight Skin (TS) and aged-matched CB57BL/6 mice were examined. The TS mice spontaneously developed emphysema-like alveolar enlargement. In vivo micro-computed tomography (microCT) scanning and histology were used as reference methods.
  
  
  RESULTS
  MR signal and T2* were significantly lower in the lungs of TS mice than in controls. There were no significant differences between the different age groups. MR signal in lung parenchyma correlated linearly (P < 0.0001, r = 0.89) with microCT mass density, and T2* correlated linearly (P < 0.0001, r = -0.91) with the alveoli size (mean linear intercept [MLI]).
  
  
  CONCLUSIONS
  The MR signal intensity and T2* measured at short tds can be used as imaging biomarkers to characterize parenchyma density and alveolar size, respectively.
authors.affiliation: DECS Imaging, AstraZeneca, Mölndal, Sweden. lars.e.olsson@astrazeneca.com
authors.forename: Lars E
authors.initials: LE
authors.lastname: Olsson
authors.forename: Maria
authors.initials: M
authors.lastname: Lindahl
authors.forename: Per-Ola
authors.initials: PO
authors.lastname: Onnervik
authors.forename: Lars B
authors.initials: LB
authors.lastname: Johansson
authors.forename: Malin
authors.initials: M
authors.lastname: Palmér
authors.forename: Martina Kvist
authors.initials: MK
authors.lastname: Reimer
authors.forename: Leif
authors.initials: L
authors.lastname: Hultin
authors.forename: Paul D
authors.initials: PD
authors.lastname: Hockings
mesh_terms: D000367:Age Factors; D000818:Animals; D004195:Disease Models, Animal; D018450:Disease Progression; D004646:Emphysema / Q000175:diagnosis*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D051379:Mice; D012815:Signal Processing, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods