Koch Robert W, Elfarnawany Mai, Zhu Ning, Ladak Hanif M, Agrawal Sumit K
*Biomedical Engineering Graduate Program†Department of Otolaryngology-Head and Neck Surgery, Western University, London, Ontario‡Canadian Light Source Inc., Saskatoon, Saskatchewan§Department of Medical Biophysics||Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada.
Otol Neurotol. 2017 Jul;38(6):e92-e99. doi: 10.1097/MAO.0000000000001410.
Evaluation of cochlear duct length (CDL) using novel imaging techniques will help improve the accuracy of existing CDL equations.
Various relationships relating A value measured from a patient's computed tomography scan and CDL have been proposed to aid in preoperative electrode selection and frequency mapping.
Ten cadaveric temporal bones were scanned using synchrotron radiation phase-contrast imaging. Reference CDL values were calculated by placing points representing the organ of Corti (OC), lateral wall (LW), and electrode location (I) on the synchrotron radiation phase-contrast imaging slices along the length of the cochlea. The CDL estimates from the existing three equations (OC, LW, I) in addition to two newly proposed equations (OC and LW) were compared with reference CDL values at each respective location.
When compared with reference CDL values, the new OC equation improved the CDL estimates from a 6.2% error to a 5.1% error while the new LW equation improved the CDL estimate error from 3.9 to 3.6%. Bland-Altman plots revealed both new equations increased similarity to reference values and brought more samples to within clinically significant ranges. Validation of the original electrode location equation to the reference values showed a 4.6% difference.
The newly proposed equations for LW and OC provided an improvement over past equations for determining CDL from the A value by showing improved agreement with reference values. Therefore, these equations can provide quick and accurate preoperative estimates of CDL for improving customized frequency mapping.
使用新型成像技术评估蜗管长度（CDL）将有助于提高现有CDL方程的准确性。
已经提出了各种将患者计算机断层扫描测量的A值与CDL相关联的关系，以辅助术前电极选择和频率映射。
使用同步辐射相衬成像对10个尸体颞骨进行扫描。通过在沿耳蜗长度的同步辐射相衬成像切片上放置代表柯蒂氏器（OC）、外侧壁（LW）和电极位置（I）的点来计算参考CDL值。将现有三个方程（OC、LW、I）以及两个新提出的方程（OC和LW）的CDL估计值与每个相应位置的参考CDL值进行比较。
与参考CDL值相比，新的OC方程将CDL估计误差从6.2%提高到5.1%，而新的LW方程将CDL估计误差从3.9%提高到3.6%。布兰德-奥特曼图显示，两个新方程都增加了与参考值的相似性，并使更多样本落在临床显著范围内。原始电极位置方程与参考值的验证显示差异为4.6%。
新提出的LW和OC方程在根据A值确定CDL方面比过去的方程有所改进，与参考值的一致性更好。因此，这些方程可以提供快速准确的术前CDL估计，以改善定制频率映射。
