A-mode ultrasound in the diagnosis of chronic polypous sinusitis.

A-mode ultrasound (A-US) is a simple, non-invasive and non-ionizing method for detecting fluid or even mucosal swelling in inflamed maxillary and frontal sinuses. A-US has been shown to be a quite reliable tool in the diagnosis of acute maxillary sinusitis. However, controversy still exists over the reliability of A-US in detecting fluid retention or mucosal swelling in patients suffering from chronic polypous rhinosinusitis or in transantrally operated maxillary sinuses. We have compared the results of maxillary sinus A-US with computed tomography (CT) images in a selected series of chronic polypous rhinosinusitis comprising 40 patients. Fluid retention was seen in 20 of 79 maxillary sinuses on CT scanning. Only 6 of these 20 retentions were detected with A-US. There were 11 false positive findings. In six of these cases a back-wall echo was received through polypoid masses in the sinus. Mucosal swelling was also difficult to diagnose. The results of A-US were not easily reproduced; only in 50% of cases were identical results obtained by two investigators. We do not recommend the use of A-US to diagnose fluid retention or mucosal swelling in a patient with chronic mucosal changes in the maxillary sinus or if surgery has been performed on the anterior wall of the maxillary sinus.