[Application of HRCT multi-planar reconstruction for measuring cochlear morphology in cochlear implantation]

To explore the value of high-resolution temporal bone CT (HRCT) multi-planar reconstruction (MPR) technique for measuring cochlear morpholog in the preoperative evaluation of cochlear implant.

We retrospectively analyzed the clinical data of 80 cochlear implant recipients. The groups were investigated in our research according to the patient's sex, age and whether the inner ear is malformed or not. Temporal bone HRCT MPR was applied to analyze the measurement parameter in the standard orientation of the cochlea image: the largest distance from the round window to the lateral wall (distance A), the perpendicular distance (B) and angle of the basal turn of the cochlea relative to the midsagittal plane (γ). Reproducibility of the measured data was evaluated and the results between the different groups were compared.

Measurement of parameter values between the intraobserver and interobserver showed good reproducibility. In normal group, distance A [(8.79±0.34) mm] and perpendicular distance B [(6.58±0.28) mm] of males' cochleae were significantly larger than A [(8.53±0.47) mm] and B [(6.22±0.43) mm] of females' (P<0.05), but the angle γ was not significantly different between the two groups (P>0.05). The A and B values didn't change with age (P>0.05), but the angle γ tended to decrease with increasing age (r=-0.25, P<0.05). In the malformation group, the value B was significantly smaller than that of the normal group (P<0.01), but for value A and angle γ, there was no significant difference between the two groups (P>0.05).

HRCT MPR technique is simple and reliable in measurement of cochlear morphology. It can be used to guide the surgery and provide an objective basis for designing the personalized electrode. More clinical application of this technology is recommended.