Diagnostic Yield of Computed Tomography Scan for Pediatric Hearing Loss: A Systematic Review

Abstract

Background Computed tomography (CT) has been used in the assessment of pediatric hearing loss, but concern regarding radiation risk and increased utilization of magnetic resonance imaging (MRI) have prompted us toward a more quantitative and sophisticated understanding of CT’s potential diagnostic yield. Objective To perform a systematic review to analyze the diagnostic yield of CT for pediatric hearing loss, including subgroup evaluation according to impairment severity and laterality, as well as the specific findings of enlarged vestibular aqueduct and narrow cochlear nerve canal. Data Sources PubMed, EMBASE, and the Cochrane Library were assessed from the date of their inception to December 2013. In addition, manual searches of bibliographies were performed and topic experts were contacted. Review Methods Data from studies describing the use of CT in the diagnostic evaluation of pediatric patients with hearing loss of unknown etiology were evaluated, according to a priori inclusion/exclusion criteria. Two independent evaluators corroborated the extracted data. Heterogeneity was evaluated according to the I2 statistic. Results In 50 criteria-meeting studies, the overall diagnostic yield of CT ranged from 7% to 74%, with the strongest and aggregate data demonstrating a point estimate of 30%. This estimate corresponded to a number needed to image of 4 (range, 2–15). The most commonly identified findings were enlarged vestibular aqueduct and cochlear anomalies. The largest studies showed a 4% to 7% yield for narrow cochlear nerve canal. Conclusion These data, along with similar analyses of radiation risk and risks/benefits of sedated MRI, may be used to help guide the choice of diagnostic imaging.

Diagnosis and Treatment of Congenital Sensorineural Hearing Loss

“…Systematic reviews concluded that the diagnostic yield of imaging studies is approximately 30% for CT and 26% for MRI, respectively. 40,41 Imaging studies provide important information about anatomic variation in patients and can guide surgical planning for cochlear implantation; however, decision regarding timing of imaging must take into account risks attributable to either radiation exposure or sedation. If no significant management alterations would derive from imaging findings, one may consider deferring imaging until the child is old enough to undergo MRI without sedation, unless a non-sedated MRI protocol is available.…”

Diagnosis and Management of Congenital Sensorineural Hearing Loss

“…A systematic review of 50 studies demonstrated that the diagnostic yield for temporal bone CT scans ranges from 7 to 74 % with a pooled diagnostic yield of 30 % and so; on average, four patients need to undergo a CT scan to yield one relevant diagnostic result [24]. Lin et al found that anomalies in the temporal bone were found in 18 % of children with severe to profound SNHL and the most commonly found anomalies were cochlear dysplasia (10.2 %), semicircular canal/vestibular dysplasia (10.2 %), IAC/CA anomalies (7.3 %), and enlarged vestibular aqueducts (5.3 %) [25].…”

Clinical Challenges in Diagnosing the Genetic Etiology of Hearing Loss

“…CT will identify anatomic abnormalities in ∼ 30% of cases of pediatric SNHL [25] , including middle and inner ear dysplasias such as Mondini dysplasia. Intracranial calcifications suggest human cytomegalovirus (HCMV) or toxoplasmosis infections.…”

“…CT provides superior definition of the bony middle and inner ear structures, including the ossicles, cochlea and semicircular canals, but carries the risk of radiation to a young child [25] . In addition, a normal bony internal auditory canal on CT does not rule out an absent or small auditory nerve.…”