<prompt> Best diagnostic aid for Bronchiectasis isBronchoscopyX-rayBronchographyCT scan  <response>: D CT scan Bronchography, the previous gold standard for diagnosing bronchiectasis, has been largely replaced by CT. Though, CT is not as sensitive as bronchography, it is considerably safer and can be done sequentially to follow the patients course. Thin-section high resolution CT HRCT may be needed. A CT scan after inhalation of xenon may prove even more sensitive. 