Preoperative imaging assessment of cochlear implant candidates: the integrative role of MDCT and MRI

Background: We explored the strength and weaknesses of Multi-detector computed tomography (MDCT) and Magnetic resonance imaging (MRI) in the preoperative evaluation of cochlear implant candidates. Methods: A retrospective study including 13 adults and 38 pediatric patients who suffered from bilateral profound sensory neural hearing loss (SNHL) and underwent MDCT and MRI examination as a preoperative assessment for cochlear implant procedures. All patients underwent high-resolution spiral MDCT (128-slice) and 1.5 T MRI examination. Records of health history and physical ear examination, audiometry results, and operative data were collected and compared with imaging findings. Results: MDCT was superior in the demonstration of middle ear disease while MRI was more useful in the delineation of the cochlear nerve and cochlear patency as well as the detection of central causes of SNHL. Only 15% of adult patients had a positive clinical concern and showed positive imaging findings. All adult patients that had no clinical concern showed no significant imaging findings. About 36.8% of pediatric patients had a positive clinical concern and showed positive imaging findings. About 33.3% of pediatric patients who had no clinical concern showed positive imaging findings. The surgical plan was changed based on combined imaging findings in 15.4% of adult patients and 39.4% of pediatric patients. Conclusion: Multi-detector computed tomography and Magnetic resonance imaging are useful in the evaluation of congenital anomalies of the inner ear. MRI is superior in the evaluation of the cochlear nerve, early detection of labyrinthine fibrosis and detection of intrauterine causes of SNHL. MDCT is helpful in evaluation of middle ear pathology and also enables a detailed evaluation of the osseous anatomy. Integrative employment of both modalities in preoperative assessment of cochlear implant candidates is recommended.