Is CT necessary for imaging paediatric congenital sensorineural hearing loss?

Objectives

To determine if MRI alone is adequate for pre-operative assessment of paediatric congenital sensorineural hearing loss (SNHL). While aberrant intratemporal facial nerve anatomy is usually occult on MRI, we postulate that the majority of cases have no adverse bearing on surgical outcomes.

Methods

MRI and CT of the temporal bones were analysed in 240 children who underwent both on the same day for SNHL. Only children under the age of 5 years with no reported clinical syndrome or dysmorphic external ear anatomy were included.Results and discussion: 169 patients satisfied the inclusion criteria. MRI detected 32/54 cases of cochleovestibular dysplasia, with the majority of the additional CT findings comprising subtle incomplete partition type 2 (IP2) anomalies. Of the 22 cases not evident on MRI, 13 patients also had large vestibular aqueduct syndromoe (LVAS), which would have prompted evaluation with CT due to the near universal co-existence of these entities. Only one patient exhibited aberrant intratemporal facial nerve anatomy that may have conferred surgical risk and was occult on MRI.

Conclusion

In a defined paediatric SNHL cohort, the addition of routine temporal bone CT to MRI offers limited additional yield but confers a significant radiation burden on a young population.