Sensitivity and Specificity of US and CT as Diagnostic Tools for Pediatric Lateral Neck Abscesses.

OBJECTIVE: Ultrasound (US) and computed tomography (CT) are commonly used in the diagnosis of pediatric neck abscesses. The objective of this study is to determine the sensitivity and specificity of US and CT in the diagnosis of pediatric lateral neck abscesses, with a secondary objective of evaluating the association of specific clinical features with a positive US or CT scan.

STUDY DESIGN: Retrospective review of pediatric patients admitted to a tertiary care center from January 1, 2011, to December 31, 2020, with neck abscesses.

SETTING: Tertiary care center.

METHODS: The sensitivity and specificity of US and CT were calculated by comparing imaging performed within 24 h of incision and drainage (I&D). Multiple regression was used to evaluate the association of clinical features with a true positive US or CT.

RESULTS: There were 171 patients included in this study, with a median age of 1.5 years (interquartile range [IQR]: 1-5 years). I&D was done in 156 patients (91.2%), while 15 (8.8%) were treated with antibiotics. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of US were 69.5%, 80%, 96.6%, and 24.2%. The sensitivity, specificity, PPV, and NPV of neck CT were 95.5%, 80%, 95.5%, and 57.1%. Length of symptoms, skin erythema, and fluctuance were not significantly associated with a positive US (F(3, 82) = 0.24, p = .9, R  = 0.01) or CT scan (F(3, 30) = 0.84, p = .5, R  = 0.08).

CONCLUSION: Neck US has a low sensitivity for diagnosing pediatric neck abscesses, when compared to CT, but remains a useful initial investigation given its high PPV. Clinicians should have a low threshold for pursuing CT if there is a high suspicion of abscess formation.

LEVEL OF EVIDENCE: Level 4.