Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Dec;35(12):5375-84.
doi: 10.1118/1.3005479.

Automatic segmentation of the facial nerve and chorda tympani in CT images using spatially dependent feature values

Jack H Noble  1 , Frank M Warren, Robert F Labadie, Benoit M Dawant
Affiliations

Automatic segmentation of the facial nerve and chorda tympani in CT images using spatially dependent feature values

Jack H Noble et al. Med Phys. 2008 Dec.

Abstract

In cochlear implant surgery, an electrode array is permanently implanted in the cochlea to stimulate the auditory nerve and allow deaf people to hear. A minimally invasive surgical technique has recently been proposed-percutaneous cochlear access-in which a single hole is drilled from the skull surface to the cochlea. For the method to be feasible, a safe and effective drilling trajectory must be determined using a preoperative CT. Segmentation of the structures of the ear would improve trajectory planning safety and efficiency and enable the possibility of automated planning. Two important structures of the ear, the facial nerve and the chorda tympani, are difficult to segment with traditional methods because of their size (diameters as small as 1.0 and 0.3 mm, respectively), the lack of contrast with adjacent structures, and large interpatient variations. A multipart, model-based segmentation algorithm is presented in this article that accomplishes automatic segmentation of the facial nerve and chorda tympani. Segmentation results are presented for ten test ears and are compared to manually segmented surfaces. The results show that the maximum error in structure wall localization is approximately 2 voxels for the facial nerve and the chorda, demonstrating that the method the authors propose is robust and accurate.

PubMed Disclaimer

Figures

Figure 1
Figure 1
3D rendering of the structures of the left ear. (a) Left-right, posterior-anterior view. (b) Posterior-anterior view.
Figure 2
Figure 2
Picture taken during clinical testing of percutaneous CI method.
Figure 3
Figure 3
Illustration of the complexity of the problem. Panels (a) and (c) are axial and (b) and (d) are coronal slices through the middle ear.
Figure 4
Figure 4
Illustration of the shape variation of the chorda between two patients with highly visible anatomy. Patient 1 [(a),(b)] and 2 [(c),(d)] in axial [(a),(c)] and parasagittal [(b),(d)] view.
Figure 5
Figure 5
Model data. (a) and (b) show intensity data for the facial nerve and chorda. (c) illustrates the average structure orientation and width.
Figure 6
Figure 6
Flow chart of the segmentation process.
Figure 7
Figure 7
Methods for calculating error between automatically and manually generated structure surfaces.
Figure 8
Figure 8
Segmentation results for CT volumes 4-R (top row), 1-L (middle row), and 3-L (bottom row).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Labadie R. F., Choudhury P., Cetinkaya E., Balachandran R., Haynes D. S., Fenlon M., Juscyzk S., and Fitzpatrick J. M., “Minimally-invasive, image-guided, facial-recess approach to the middle ear: Demonstration of the concept of percutaneous cochlear access in-vitro,” Otol. Neurotol. ONTEAE 26, 557–562 (2005). - PubMed
    1. Labadie R. F., Noble J. H., Dawant B. M., Balachandran R., Majdani O., and Fitzpatrick J. M., “Clinical validation of percutaneous cochlear implant surgery: Initial report,” Laryngoscope LARYA8 118, 1031–1039 (2008). - PMC - PubMed
    1. Fitzpatrick J. M., Konrad P. E., Nickele C., Cetinkaya E., and Kao C., “Accuracy of customized miniature stereotactic platforms,” Stereotact. Funct. Neurosurg. ZZZZZZ 83, 25–31 (2005). - PubMed
    1. Noble J. H., Warren F. M., Labadie R. F., Dawant B. M., and Fitzpatrick J. M., “Determination of drill paths for percutaneous cochlear access accounting for target positioning error,” Proc. SPIE PSISDG 6509, 650925.1–650925.10 (2007).
    1. Rueckert D., Sonoda L. I., Hayes C., Hill D. L. G., Leach M. O., and Hawkes D. J., “Nonrigid registration using free-form deformations: Application to breast MR images,” IEEE Trans. Med. Imaging ITMID410.1109/42.796284 18, 712–721 (1998). - DOI - PubMed

Publication types