Quantitative analysis of dynamic airway changes after methacholine and salbutamol inhalation on xenon-enhanced chest CT.
OBJECTIVE
To investigate the dynamic changes in airways in response to methacholine and salbutamol inhalation and to correlate the xenon ventilation index on xenon-enhanced chest CTs in asthmatics.


METHODS
Thirty-one non-smokers (6 normal, 25 asthmatics) underwent xenon-enhanced chest CT and pulmonary function tests. Images were obtained at three stages (basal state, after methacholine inhalation and after salbutamol inhalation), and the total xenon ventilation index (TXVI) as well as airway values were measured and calculated. The repeated measures ANOVA and Spearman's correlation coefficient were used for statistical analysis.


RESULTS
TXVI in the normal group did not significantly change (P > 0.05) with methacholine and salbutamol. For asthmatics, however, the TXVI significantly decreased after methacholine inhalation and increased after salbutamol inhalation (P < 0.05). Of the airway parameters, the airway inner area (IA) significantly increased after salbutamol inhalation in all airways (P < 0.01) in asthmatics. Airway IA, wall thickness and wall area percentage did not significantly decrease after methacholine inhalation (P > 0.05). IA of the large airways was well correlated with basal TXVI, FEV(1) and FVC (P < 0.05).


CONCLUSIONS
Airway IA is the most reliable parameter for reflecting the dynamic changes after methacholine and salbutamol inhalation, and correlates well with TXVI in asthmatics on xenon-enhanced CT.


CONCLUSIONS
• In asthmatics, xenon ventilation decreases after methacholine and increases after salbutamol inhalation.                 • Inner airway area (IA) correlates well with xenon ventilation.                 • IA is the most reliable parameter reflecting airway changes in drug responses.
Department of Radiology, Seoul National University College of Medicine, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea.
Sang Joon
SJ
Park
Chang Hyun
CH
Lee
Jin Mo
JM
Goo
Jong Hyo
JH
Kim
Eun-Ah
EA
Park
Jae-Woo
JW
Jung
Heung-Woo
HW
Park
Sang-Heon
SH
Cho
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D000420:Albuterol / Q000494:pharmacology*; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D001239:Inhalation; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology*; D008875:Middle Aged; D012119:Respiration; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014978:Xenon / Q000627:therapeutic use*
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D014978:Xenon; D000420:Albuterol