METHOD AND MATERIALS: We used a 128-MDCT scanner providing 1024 x 1024 matrix (Ingenuity, Philips Healthcare). CT scan was performed in 10 wild type mice and two radiologists analyzed the quality of airway images in each corresponding generation illustrated by the micro-CT scan in addition to the cardiac and respiratory motion artifacts. Five OVA-sensitized C57BL/6 mice were challenged with OVA and other five mice were challenged with methacholine. The airway inner area was measured in the mid-trachea and left main bronchus. The degree of peribronchial inflammation was graded by the consensus of two radiologists in the five lobes.
RESULTS: The 1024x1024 matrix MDCT scan showed comparable image quality and airway depiction to the micro-CT. Among twenty four airways, trachea, LMB1, LBA2, LMB2, RMB1, RMB2, CaRMB3, CaRMB4, CaRMB5, MiRMB3 and AcRMB3 were 100% depicted; LBB3, LMB3, LMB4, CrRMB2, CaRBA4 in 90%; LBC4, CrRBA3, CrRMB3, CrRBB4 in 80%; LMB5, CrRMB4 in 70%; CrRBA4 in 60%; and LBA3 in 50% (k = 0.89). The motion artifact was not seen in all mice but cardiac motion artifact was seen in 60% but 83.3% was mild degree and 16.7% was moderate. The trachea showed decreased inner area after methacholine challenge after 5 minutes (p<0.05) but OVA challenge did not show significant changes in both trachea and LMB. Methacholine challenge showed no parenchymal changes in the lungs but OVA challenge showed peribronchial GGO or consolidation in 60% (3/5).
CONCLUSION: High matrix MDCT showed excellent quality of airway visualization with high agreement between readers. While tracheal inner area was significantly decreased after methacholine challenge, peribronchial inflammation was seen only in the case of OVA challenge in ovalbumin-sensitized mice.