title: CT differentiation of abscess and non-infected fluid in the postoperative neck.
abstract: BACKGROUND
  Differentiation of postoperative neck abscess from non-infected fluid is important because the treatment is different.
  
  
  OBJECTIVE
  To determine specific CT findings that might help to differentiate abscesses from non-infected fluid collections in the postoperative neck.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology, Kangdong Seong-Sim Hospital, Hallym University College of Medicine, Seoul, Korea.
authors.forename: Soo Jeong
authors.initials: SJ
authors.lastname: Yoon
authors.forename: Dae Young
authors.initials: DY
authors.lastname: Yoon
authors.forename: Sam Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Rho
authors.forename: Eun-Jae
authors.initials: EJ
authors.lastname: Chung
authors.forename: Joong Sik
authors.initials: JS
authors.lastname: Eom
authors.forename: Jin Seo
authors.initials: JS
authors.lastname: Lee
mesh_terms: D000038:Abscess / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003287:Contrast Media; D003937:Diagnosis, Differential; D004322:Drainage; D005260:Female; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol