Measurement Accuracy of CBCT Versus MDCT for the Linear Distance between the Stapes and Round Window, and the Incudostapedial Joint Thickness for Cochlear Implantation Treatment Planning.

Objectives: This study aimed to compare the measurement accuracy of cone-beam computed tomography (CBCT) and multi-detector computed tomography (MDCT) for the linear distance between the stapes and round window, and the incudostapedial joint thickness for cochlear implantation treatment planning.

Materials and methods: In this in vitro study, 12 temporal bones along with their covering soft tissue underwent high-resolution (HR) and low-resolution (LR) CBCT and MDCT. The linear distance between the stapes and round window as well as the incudostapedial joint thickness were measured on images by an oral radiologist and a general radiologist. Data were analyzed by paired t-test, Wilcoxon test and Pearson's correlation test (alpha=0.05).

Results: Significant correlations and excellent agreement were noted between HR-CBCT and MDCT, HR-CBCT and LR-CBCT, and LR-CBCT and MDCT in both measurements (P<0.05). The mean distance between the stapes and round window on HR-CBCT was significantly higher than that on MDCT and LR-CBCT, and there were significant differences in the measurement accuracy of HR-CBCT with MDCT (P=0.014) and LR-CBCT (P=0.027). The difference between LR-CBCT and MDCT was not significant (P=0.102). The mean joint thickness on HR-CBCT was significantly higher than that on MDCT and the measurement accuracy of CBCT and MDCT was significantly different in this respect (P=0.014). The differences between LR-CBCT and MDCT, and HR-CBCT and LR-CBCT were not significant (P<0.05).

Conclusions: The results of the present study showed an acceptable accuracy of CBCT comparable to that of MDCT for measurement of the linear distance between the stapes and round window, and the incudostapedial joint thickness for cochlear implantation treatment planning.