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A Novel Radiographic Sign and a New Classifying System in Mastoiditis-Related Epidural Abscess
Gilad Horowitz1, Gadi Fishman, Adi Brenner
1Department of *Otolaryngology, Head & Neck and Maxillofacial Surgery and Pediatric ENT Unit and †Radiology and Neuroradiology Unit, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Insights
A new radiographic sign, the "halo" sign, and classification system for perisigmoid epidural abscesses were developed. Gross changes suggest abscess requiring surgery.
Area of Science:
- Radiology
- Pediatric Otolaryngology
- Neurosurgery
Background:
- Perisigmoid epidural abscesses are a complication of acute mastoiditis.
- Accurate radiographic assessment is crucial for timely surgical intervention.
Purpose of the Study:
- To introduce a novel radiographic sign, the "halo" sign, for evolving perisigmoid epidural abscess.
- To present a new classification system for these abscesses.
- To correlate imaging findings with intraoperative results.
Main Methods:
- Retrospective and prospective cohort study (26 children total).
- Classification of computerized tomographic (CT) appearance into four groups (Class I-IV) based on "halo" sign characteristics.
- Comparison of CT findings with intraoperative surgical observations.
Main Results:
- Highly significant correlation between preoperative imaging and intraoperative findings in both retrospective (p=0.007) and prospective (p=0.005) arms.
- High interobserver agreement for the classification method (Cohen kappa=0.76, weighted kappa=0.84).
Conclusions:
- A novel "halo" sign and classification system for perisigmoid epidural abscesses are described.
- A smooth halo sign does not indicate abscess, but gross changes suggest abscess requiring surgery.
Objective:
To describe a novel radiographic sign ("halo") and a new classification method of an evolving perisigmoid epidural abscess and present its correlation with intraoperative findings.
Study Design:
Retrospective and prospective cohort study in a tertiary academic children's hospital.
Methods:
The retrospective arm (15 children) was conducted between 1998 and 2007 and the prospective arm (11 children) between 2008 and 2013. The computerized tomographic appearance of the perisigmoid region was classified into four groups: Class I, normal; Class II, smooth halo; Class III, nodular halo 4 mm or less in diameter; and Class IV, gross nodular halo more than 4 mm in diameter. Intraoperative findings of the perisigmoid region were compared with the preoperative scan results.
Results:
The correlation between preoperative imaging and intraoperative findings of the retrospective arm was highly significant (p = 0.007). The correlation between the preoperative imaging studies and intraoperative findings of the prospective arm was also highly significant (p = 0.005). The interobserver agreement for the proposed classification method was high (Cohen kappa score, 0.76; weighted kappa score, 0.84).
Conclusion:
A novel radiographic sign ("halo") and a new classification method for an evolving perisigmoid epidural abscess in acute mastoiditis are described. A thin and smooth halo sign is not indicative of a true abscess formation. Gross perisigmoid granular changes, however, are highly suggestive of an epidural abscess that warrants surgical intervention.
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Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...