Incidental Finding of Mastoiditis Due to Imaging Test Opacity Does Not Constitute Clinical Diagnosis

How prevalent is incidental mastoid opacification (IMO) in the use of cross-sectional imaging, and what is the clinical need for assessment or intervention when IMO is identified?

BOTTOM LINE

The term “mastoiditis” on radiology reports based on IMO does not indicate a clinical diagnosis of mastoiditis, so otolaryngology review is suggested if clinical examination detects ontological signs or symptoms.

BACKGROUND: Greater cross-sectional imaging use has led to an increase in “incidental findings.” Radiology reports may state incidental findings of mastoiditis based on observations of mastoid opacification, prompting a referral to otolaryngology. However, a radiological diagnosis of mastoiditis based solely on IMO can lead to unnecessary treatment escalation.

STUDY DESIGN: Systematic review and meta-analysis.

SETTING: Department of Otolaryngology, Warwick Hospital, South Warwickshire NHS Foundation Trust, Warwick, U.K.

SYNOPSIS: Researchers performed a systematic review and meta-analysis of multiple studies to assess the prevalence of IMO and presence of true mastoiditis within the patient group. Investigators identified 15 studies suitable for qualitative and quantitative meta-analysis, comprising 246,288 patients with IMO findings on computed tomography (CT) or magnetic resonance imaging (MRI) scans of the craniofacial area. The pooled prevalence of IMO was 8.4% (17.1% in children, 6.1% in adults). No significant difference was found in IMO rates between CT and MRI. Nine studies reported on clinical outcomes of patients with IMO, and none reliably reported any cases of clinical mastoiditis. Their findings indicated that IMO had a negligible detection rate for true mastoiditis or other ear pathology, suggesting that, in such cases, a history and examination of the ear might be advised prior to referral to an otolaryngologist. Study limitations were primarily related to the methodology of the included studies, which were mostly retrospective and, therefore, not robust enough to detect cases of true mastoiditis.

CITATION: Mughal Z, Charlton AR, Clark M. The prevalence of incidental mastoid opacification and the need for intervention: a meta-analysis. Laryngoscope. 2022;132:422-432.