CT differentiation of abscess and non-infected fluid in the postoperative neck

<jats:sec><jats:title>Background</jats:title><jats:p>Differentiation of postoperative neck abscess from non-infected fluid is important because the treatment is different.</jats:p></jats:sec><jats:sec><jats:title>Purpose</jats:title><jats:p>To determine specific CT findings that might help to differentiate abscesses from non-infected fluid collections in the postoperative neck.</jats:p></jats:sec><jats:sec><jats:title>Material and Methods</jats:title><jats:p>We retrospectively reviewed CT scans of 50 patients (43 men and 7 women; mean age, 62.5±8.9 years) who had postoperative fluid collections in the neck (26 abscesses and 24 non-infected fluid collections). Diagnosis of an abscess was determined by a positive bacteria culture from the fluid collection. Diagnoses were correlated with the following CT findings: anatomic spaces involved, the maximum transverse diameter, margin, attenuation, rim enhancement, gas bubbles, and manifestations of soft tissue adjacent to a fluid collection.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Rim enhancement pattern and soft tissue manifestations showed significant differences between abscess and non-infected fluid. The reliable CT findings for abscess were: (i) rim enhancement,> 50% of the circumference, 54% sensitive, 71% specific, and 62% accurate; and (ii) severe soft tissue manifestations, 39% sensitive, 92% specific, and 64% accurate. There were no significant differences in the anatomic spaces involved, the maximum transverse diameter, margin, attenuation, and gas bubbles between abscess and non-infected fluid.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>CT findings that may help differentiate postoperative neck abscess from non-infected fluid were rim enhancement > 50% of the circumference and severe soft tissue manifestations.</jats:p></jats:sec>