Correlation of asthma severity, IgE level, and spirometry results with HRCT findings in allergic bronchopulmonary aspergillosis

CONTEXT: Few studies have been done for correlating asthma severity, IgE level, and spirometry results with high-resolution computed tomographic (HRCT) findings in allergic bronchopulmonary aspergillosis (ABPA). AIMS: This prospective observational study was conducted to correlate asthma severity, IgE level, and spirometry results with HRCT findings in ABPA. SETTINGS AND DESIGN: Prospective observational. SUBJECTS AND METHODS: Fifty consecutive adult patients with asthma and positive specific IgE (>0.35 kUA/L) to Aspergillus fumigatus were recruited from October 2015 to July 2017. Asthma severity, IgE levels, and spirometry results were correlated with HRCT score, bronchiectasis score, air trapping segments, and low-attenuation lung volume on inspiratory CT and expiratory CT. STATISTICAL ANALYSIS USED: One way ANOVA, Spearman's correlation coefficients. RESULTS: Asthma severity showed a significant positive correlation with HRCT score and bronchiectasis score. MEF pre and postbronchodilator values showed a significant negative correlation with HRCT score, bronchiectasis score, and percentage expiratory volumes -851 to -950 HU voxels. FEV1 prebronchodilator value showed a significant negative correlation with percentage expiratory volume -851 to -950 HU voxels and percentage expiratory volume -851 to -1024 HU voxels. Specific IgE antibody level showed a significant positive correlation with bronchiectasis score. CONCLUSIONS: Asthma severity, specific IgE level, and MEF values showed a good correlation with HRCT findings. The restrictive pattern is common on spirometry in patients of ABPA. In addition to central bronchiectasis, peripheral bronchial and small airway involvement was an important finding in ABPA. Expiratory HRCT may reveal air trapping in patients having no abnormality on inspiratory CT.