A Comparative Utility Study of Computed Tomography Versus Magnetic Resonance Imaging in the Preoperative Assessment of Adult Cochlear Implant Candidates.

OBJECTIVE

To compare the clinical utility of computed tomography (CT) and magnetic resonance imaging (MRI) for the preoperative workup of adult cochlear implant (CI) candidates.

STUDY

DESIGN

Retrospective chart review.

SETTING

Single tertiary care center.

PATIENTS: Four hundred ninety-six consecutive adults who underwent preoperative candidacy evaluation before cochlear implantation.

MAIN OUTCOME MEASURES: Positive findings on CT or MRI, perioperative outcomes, and device outcome measures [active electrodes, AzBio sentence scores, consonant-nucleus-consonant (CNC) word scores, and consonant-nucleus-consonant phoneme scores].

RESULTS

Four hundred ninety-six subjects were included. Mean age was 63.8 years (SD = 16.1). Three hundred seventy-two patients (75.0%) had preoperative MRI scans, 329 patients (66.3%) had CT scans, and 217 patients (43.8%) had both. Positive MRI findings led to a change in surgical management in 7 cases (1.9%): 3 decreased cochlear signal, 1 labyrinthitis ossificans, 1 cochlear malformation, 1 petrous apex lesion, and 1 vestibular schwannoma. CT led to change in management in 15 cases (4.6%): 5 labyrinthitis ossificans, 3 aberrant facial nerve, 4 sclerotic mastoid, 1 obstructing jugular bulb, 1 cochlear malformation, and 1 petrous apex lesion. Among 36 subjects with initial CT, 2 (5.6%) required subsequent MRI imaging; no subjects with initial MRI required additional CT imaging. No differences were found between imaging groups across device outcomes.

CONCLUSIONS

Both CT and MRI are suitable for preoperative planning before CI. CT is cost-effective and provides insight into surgical anatomy; however, MRI is the preferred single-modality option when indicated for providing definitive diagnostic information.