Evaluation of micro-CT for emphysema assessment in mice: comparison with non-radiological techniques.
OBJECTIVE
To define the potential, limitations and synergies of micro-CT and other non-radiological techniques for the quantification of emphysema and related processes in mice, by performing a complete characterization of the elastase-induced emphysema model.


METHODS
Ninety A/J mice (45 treated and 45 controls) were studied at different time points using breath-hold gated micro-CT, functional test parameters, RT-PCR for RNA cytokine expression, Luminex technology for cytokine plasma concentration and histomorphometry.


RESULTS
Both histomorphometry and micro-CT imaging reflect rapid initial emphysema progression followed by steady-state development at decreasing rates. Cytokine measurements reveal an acute inflammatory response within the first 24 h that disappears after the first week. Limited systemic effect was observed based on plasma cytokine concentration. Lung compliance decreases during the acute inflammation phase and increases afterwards.


CONCLUSIONS
Histomorphometry is the most sensitive technique since it detects airspace enlargement before the other methods (1 h after treatment). Micro-CT correlates well with histology (r2 = 0.63) proving appropriate for longitudinal studies. Functional test parameters do not necessarily correlate with the extent of emphysema, as they can be influenced by acute inflammation. Finally, cytokine measurements correlate with the presence of inflammation in histology but not with emphysema.
Cancer Imaging Laboratory, Oncology Division, Center for Applied Medical Research, University of Navarra, 55 Pio XII, 31008 Pamplona, Spain. xabiarta@unav.es
Xabier
X
Artaechevarria
David
D
Blanco
Gabriel
G
de Biurrun
Mario
M
Ceresa
Daniel
D
Pérez-Martín
Gorka
G
Bastarrika
Juan P
JP
de Torres
Javier J
JJ
Zulueta
Luis M
LM
Montuenga
Carlos
C
Ortiz-de-Solorzano
Arrate
A
Munoz-Barrutia
D000818:Animals; D016207:Cytokines / Q000378:metabolism; D018450:Disease Progression; D004646:Emphysema / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007249:Inflammation; D008168:Lung / Q000473:pathology; D008297:Male; D051379:Mice; D010196:Pancreatic Elastase / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D055114:X-Ray Microtomography / Q000379:methods*
D016207:Cytokines; D012313:RNA; D010196:Pancreatic Elastase