Dependence of Cochlear Duct Length Measurement on the Resolution of the Imaging Dataset

Hypothesis: Measurements of the cochlear duct length (CDL) are dependent on the resolution of the imaging dataset. Background: Previous research has shown highly precise cochlear measurements using 3D-curved multiplanar reconstruction (MPR) and flat-panel volume computed tomography (fpVCT). Thus far, however, there has been no systematic evaluation of the imaging dataset resolution required for optimal CDL measurement. Therefore, the aim of this study was to evaluate the dependence of CDL measurement on the resolution of the imaging dataset to establish a benchmark for future CDL measurements. Methods: fpVCT scans of 10 human petrous bone specimens were performed. CDL was measured using 3D-curved MPR with secondary reconstruction of the fpVCT scans (fpVCTSECO) and increasing resolution from 466 to 99 μm. In addition, intraobserver variability was evaluated. A best-fit function for calculation of the CDL was developed to provide a valid tool when there are no measurements done with high-resolution imaging datasets.