Peritonsillar abscess appearance on intra-oral ultrasonography.

The ultrasound appearances of peritonsillar abscesses (PTA) in 15 patients with clinically suspected peritonsillar infection were assessed using intra-oral sonography and computed tomography (CT). The ultrasonic appearances of an isoechoic rim with a hypoechoic centre were seen in the majority of cases, but a homogeneous isoechoic pattern was also recognized. The different ultrasonic appearances did not correlate with the number of symptomatic days. A central hypoechoic area with a surrounding isoechoic rim pattern was less likely if the volume of pus relative to the whole abscess was less than 10% on CT. Although the percentage of necrosis within the abscesses increased with time, the homogeneous isoechoic appearing abscesses, with less than 10% necrosis, did not fit in temporally and based on our findings it was not possible to predict the ultrasound appearances according to the duration of symptoms.