3D image of the middle ear ossicles: three protocols of post-processing based on multislice computed tomography

Multislice Spiral Computer Tomography Findings of Simple Congenital Middle Ear Malformations

Background

Simple congenital middle ear malformations (SCMEMs) are a group of congenital ear malformations. The study aims to analyze the multi-slice spiral computer tomography (MSCT) manifestations of normal ears and SCMEM ears.

Objectives

This study aimed to investigate the MSCT manifestations of normal ears and SCMEM ears and to evaluate the relationship between the SCMEM and the tympanic segment of the FNC pathway.

Methods

This was a retrospective case-control study. Patients who were diagnosed with SCMEM were included in the SCMEM group. Patients with vertigo, pulsatile tinnitus, or other symptoms were included in the control group. MSCT examination and image processing of the ossicular chain, facial nerve canal, and related structures were performed and compared between the two groups.

Results

There were 94 cases in the SCMEM group (125 ears) and 97 cases in the control group (190 ears). Sixty-three cases (67.0%) were unilateral malformations (36 right ears and 27 left ears). MSCT showed congenital stapes malformation in 107 ears (85.6%) and incus long process malformation in 84 ears (67.2%). Among these, simple stapes malformations were found in 41 ears (32.8%), simple incus malformation in 18 ears (14.4%), and stapes malformation complicated with incus malformation in 66 ears (52.8%). The distance between the facial nerve and lateral semicircular canal (FNC-LSC) in the SCMEM group was 1.30 ± 0.64 mm compared to 0.79 ± 0.11 mm in the control group (P < 0.001), and the distance between facial nerve canal and oval window (FNC-OW) was 0.67 ± 0.53 mm in the SCMEM group and 1.13 ± 0.18 mm in the control group (P < 0.001).

Conclusion

SCMEM occurred mainly in ossicular chain abnormalities. MSCT clearly showed the slight structural changes in the middle ear and provided an accurate basis for preoperative diagnosis.

Study of the Anatomical Structure of the Nasopharyngeal Cavity and Distribution of the Air Flow Field

To build a biomechanical numerical model of the nasopharynx, construct an accurate computerized numerical description of its specific anatomical structures, analyze the distribution of air flow field, starting with the anatomical structure of the pharyngeal recess, correlate its anatomical characteristics with the occurrence and development of nasopharyngeal carcinoma from the perspective of biomechanics. In this study, the nasal and nasopharyngeal cavities of healthy male adult, with the pharyngeal recess in an open state, were scanned by CT to obtain DICOM imaging data. Then, they were imported into Mimics 20.0 to build a model which was recorded in binary STL format. Each file was imported into Geomagic studio 12.0 to construct a 3D model saved in an IGES format. Then, it was imported into ANSYS Workbench for numerical simulation of air flow field. The authors found that:Above all, the causes and pathogenesis of nasopharyngeal carcinoma can be identified from the perspective of biomechanics through the construction of a 3D model and analysis of the characteristics of air flow field. With more in-depth research, it is expected that a more solid scientific foundation will be created for related quantitative analysis.

Value of section plane, MPR, and 3D-CTVR techniques in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane

Aim

To assess the quality of high-resolution CT section planes (HRCT), multi-planar reformation (MPR) and 3-dimensional volume rendered computer tomography (3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.

Methods

Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals, intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.

Results

MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations (P > 0.05).

Conclusion

CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation.

Usefulness of multislice-CT using multiplanar reconstruction in the preoperative assessment of the ossicular lesions in the middle ear diseases

OBJECTIVE

The aim of the study is to evaluate the usefulness of multislice computed tomography (MSCT) using multiplanar reconstruction (MPR) in obtaining preoperative information on the ossicular lesions of middle ear diseases by comparing the ossicular findings of MPR images with the operative findings.

METHODS

Sixty-two ears and 10 ears with preoperative middle ear diseases underwent 4- and 64-detector row CT of the temporal bone in Kagawa University Hospital, respectively. MPR images of three ossicles were created at the planes parallel to the long axis of ossicles.

RESULTS

The findings of the three ossicles in MPR images were compatible with their operative findings in approximately 91% of 72 ears with various middle ear diseases. There was no significant difference in the coincidence rate of both findings between 4- and 64-detector row CT scanners. The ears with no soft tissue shadows around the ossicles had the coincidence rate of 96-100% in each ossicular part, whereas the coincidence rate was lower in the ears with soft tissue shadows around the ossicles.

CONCLUSION

MPR imagings of the ossicles provide accurate preoperative information on the ossicular lesions in middle ear diseases. The 4-detector CT is still a useful device for imaging of the ossicles.

Panel 2

Objective

This report reviews the literature to identify the advances in our understanding of the middle ear (ME)–Eustachian tube (ET) system during the past 4 years and, on that basis, to determine whether the short-term goals elaborated in the last report were achieved and propose updated goals to guide future otitis media (OM) research.

Data Sources

Databases searched included PubMed, Web of Science (1945-present), Medline (1950 to present), Biosis Previews (1969-present), and the Zoological Record (1978 to present). The initial literature search covered the time interval from January 2007 to June 2011, with a supplementary search completed in February 2012.

Review Methods

The panel topic was subdivided; each contributor performed a literature search and provided a preliminary report. Those reports were consolidated and discussed when the panel met on June 9, 2011. At that meeting, the progress was evaluated and new short-term goals proposed.

Conclusions

Progress was made on 16 of the 19 short-term goals proposed in 2007. Significant advances were made in the characterization of ME gas exchange pathways, modeling ET function, and preliminary testing of treatments for ET dysfunction.

Implications for Practice

In the future, imaging technologies should be developed to noninvasively assess ME/ET structure and physiology with respect to their role in OM pathogenesis. The new data derived from form/function experiments should be integrated into the finite element models and used to develop specific hypotheses concerning OM pathogenesis and persistence. Finally, rigorous studies of treatments, medical or surgical, of ET dysfunction should be undertaken.