Central bronchiectasis in allergic bronchopulmonary aspergillosis: comparative evaluation of computed tomography of the thorax with bronchography.

Demonstration of central bronchiectasis (CB) with normal peripheral bronchi is an essential requirement for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). Although the results of bronchography remain the gold standard for demonstration of central bronchiectasis they are not always diagnostic. Moreover, it is an unpleasant invasive procedure which may be difficult to perform in a patient of allergic bronchopulmonary aspergillosis with acute severe asthma. In an attempt to find a safe and effective alternative to demonstrate central bronchiectasis computed tomography (CT) of the thorax was evaluated against bronchography. Twenty one patients with allergic bronchopulmonary aspergillosis underwent computed tomography of the thorax followed by bronchography. Of the 378 bronchopulmonary segments available for analysis, 42 had to be excluded because of consolidation or non-filling of the contrast dye, leaving 336 segments for evaluation. CB was identified on CT in all 21 patients. Detailed analysis of the visualized segments revealed that computed tomography (using 8 mm contiguous scans) identified 146 of the 212 segments showing central bronchiectasis on bronchography (sensitivity 70%) and 114 of the 124, read as normal on bronchography (specificity 92%). Supplemental 4 mm scans, used in 8 out of 21 patients improved the overall sensitivity of computed tomography to 83%, whilst the specificity remained unchanged at 92%. Thus, computed tomography of the thorax, being more acceptable to the patient, has the potential of being the investigation of choice for the demonstration of central bronchiectasis in patients with allergic bronchopulmonary aspergillosis.