Length measurement of cochlear parameters prior to cochlear implantation – comparison of CT- vs. MRI-based Results 

The preoperative radiological length measurement of the cochlea and the determination of the individually optimal electrode array length derived from this measurement is now an accepted procedure to achieve the most complete coverage of the frequency spectrum of the cochlea. So far, this has been based primarily on CT data sets. The aim of the present study is to evaluate to what extent the length measures obtained in this way correlate with those based on MRI data.

Evaluation of cochlear length parameters (cochlear duct length (CDL), length of the cochlea at two turns, diameter of the basal turn of the cochlea, and cochlear height) of 78 cochleae based on high-resolution CT vs. MRI examinations by 3 investigators using the tablet-based simulation program Otoplan^​. Determination of absolute lengths as well as calculation of mean absolute intrarater differences, maximum differences and intrarater reliability as well as determination of the optimal electrode array length in each case.

The CDL measured in the investigated patient collective showed a range of 30.2 to 39.8 mm based on CT and 28.7 to 39.4 mm based on MRI data. The maximum absolute intrarater difference of the CDL was 3.2 mm, and the mean intrarater difference was 0.579±0.532 on the right and 0.477±0.434 mm on the left, respectively. Based on cochlear length at 720°, when CT- and MRI-based data acquisition were compared, there were agreements in the choice of optimal electrode array in 89.7 and 90.6% of cases, respectively. The corresponding intrarater reliability between the two radiological methods was 0.65-0.84.

Radiological length measurement of the cochlea shows high agreement between CT- vs. MRI-based data. Electrode array selection based on length measurement alone yields approximately 90% agreement.

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Artikel online veröffentlicht:
24. Mai 2022