Patient-specific estimation of detailed cochlear shape from clinical CT images

PURPOSE A personalized estimation of the cochlear shape can be used to create computational anatomical models to aid cochlear implant (CI) surgery and CI audio processor programming ultimately resulting in improved hearing restoration. The purpose of this work is to develop and test a method for estimation of the detailed patient-specific cochlear shape from CT images. METHODS From a collection of temporal bone [Formula: see text]CT images, we build a cochlear statistical deformation model (SDM), which is a description of how a human cochlea deforms to represent the observed anatomical variability. The model is used for regularization of a non-rigid image registration procedure between a patient CT scan and a [Formula: see text]CT image, allowing us to estimate the detailed patient-specific cochlear shape. RESULTS We test the accuracy and precision of the predicted cochlear shape using both [Formula: see text]CT and CT images. The evaluation is based on classic generic metrics, where we achieve competitive accuracy with the state-of-the-art methods for the task. Additionally, we expand the evaluation with a few anatomically specific scores. CONCLUSIONS The paper presents the process of building and using the SDM of the cochlea. Compared to current best practice, we demonstrate competitive performance and some useful properties of our method

Highly accurate Facial Nerve Segmentation Refinement from CBCT/CT Imaging using a Super Resolution Classification Approach.

Facial nerve segmentation is of considerable importance for pre-operative planning of cochlear implantation. However, it is strongly influenced by the relatively low resolution of the cone-beam computed tomography (CBCT) images used in clinical practice. In this paper, we propose a super-resolution classification method, which refines a given initial segmentation of the facial nerve to a sub-voxel classification level from CBCT/CT images. The super-resolution classification method learns the mapping from low-resolution CBCT/CT images to high-resolution facial nerve label images, obtained from manual segmentation on micro-CT images. We present preliminary results on dataset, 15 ex-vivo samples scanned including pairs of CBCT/CT scans and high-resolution micro-CT scans, with a Leave-One-Out (LOO) evaluation, and manual segmentations on micro-CT images as ground truth. Our experiments achieved a segmentation accuracy with a Dice coefficient of 0.818 ±0.052 , surface-to-surface distance of 0.121 ±0.030mm and Hausdorff distance of 0.715 ±0.169mm . We compared the proposed technique to two other semi-automated segmentation software tools, ITK-SNAP and GeoS, and show the ability of the proposed approach to yield sub-voxel levels of accuracy in delineating the facial nerve

Facial Nerve Image Enhancement from CBCT using Supervised Learning Technique

Facial nerve segmentation plays an important role in surgical planning of cochlear implantation. Clinically available CBCT images are used for surgical planning. However, its relatively low resolution renders the identification of the facial nerve difficult. In this work, we present a supervised learning approach to enhance facial nerve image information from CBCT. A supervised learning approach based on multi-output random forest was employed to learn the mapping between CBCT and micro-CT images. Evaluation was performed qualitatively and quantitatively by using the predicted image as input for a previously published dedicated facial nerve segmentation, and cochlear implantation surgical planning software, OtoPlan. Results show the potential of the proposed approach to improve facial nerve image quality as imaged by CBCT and to leverage its segmentation using OtoPlan

Cochlear finite element modelling, Mesh quality under SSM-Driven deformations

Combining a high resolution cochlear finite element model with a/npatient low resolution CT scan could provide benefits for the use and implantation/nof cochlear implants. In order to do so requires a cochlear statistical shape/nmodel to drive the deformation fitting process. In this study we explore what/nhappens with the finite element mesh quality under these deformations. We/nsearch for a way of sanity checking the geometry of the mesh prior to running/nfinite element simulations.The research leading to HEAR-EU results has received funding from the European/nUnion Seventh Frame Programme (FP7/2007-2013) under grant agreement/nnº304857

Cochlear finite element modelling, Mesh quality under SSM-Driven deformations

Combining a high resolution cochlear finite element model with a/npatient low resolution CT scan could provide benefits for the use and implantation/nof cochlear implants. In order to do so requires a cochlear statistical shape/nmodel to drive the deformation fitting process. In this study we explore what/nhappens with the finite element mesh quality under these deformations. We/nsearch for a way of sanity checking the geometry of the mesh prior to running/nfinite element simulations.The research leading to HEAR-EU results has received funding from the European/nUnion Seventh Frame Programme (FP7/2007-2013) under grant agreement/nnº304857

Finite element model for patient-specific functional simulations of cochlear implants

We present an innovative image analyisis pipeline to perform/npatient-speci c biomechanical and functional simulations of the inner human/near. A high-resolution, cadaveric, mCT volumetric image portraying/nthe detailed geometry of the cochlea is converted into a mesh in order to/nbuild a Finite Element Method (FEM). The constitutive model for the/nFEM is based on a Navier-Stokes formulation for compressible Newtonian/n/nuid, coupled with an elastic solid model. The simulation includes/n/nuid-structure interactions. Further to this, the FEM mesh is deformed/nto a patient-speci c low-resolution Cone Beam CT (CBCT) dataset to/npropagate functional information to the speci c anatomy of the patient./nIllustrative results of how the FE-model responds to various acoustic/nstimuli are shown by analyzing the tonotopic mapping of the cochlear/nmembrane vibration.The research leading to HEAR-EU results has received funding from the European/nUnion Seventh Frame Programme (FP7/2007-2013) under grant agreement/nno. 30485

Z zdravjem povezani vidiki spolnega vedenja ljudi v Sloveniji, ki se prek interneta dogovarjajo za zmenke

Background: The article presents the results of the first sociological study in Slovenia on sexual behaviour of internet daters, with a particular focus on health-related aspects of sexual behaviour. Methods: The sample consists of people who use (have used) Internet dating services. Snow-ball sampling was done through e-mail alerts and by posting banners on Internet dating sites. The data were collected in January and February 2007. The final sample consists of 1349 respondents. Results: The majority of our respondents had either no (44.2%) or few (1 to 5 - 48%) sexual contacts with persons they got to know over the internet. Depending on their sexual orientation, 15 to 40% of men had sex on the first date compared to 7 to 18% of women. One third of heterosexual men and women did not use a condom during their first sexual intercourse with the last person met online. Homosexual men are far more likely to use condoms, as only 17% stated that they did not use a condom, in comparison with heterosexual and bisexual men. Conclusions: Results of the survey show that the time that passes between first on-line contact and first sexual intercourse represents an important indicator of potentially risky sexual behaviour as far as sexual health is concerned. Our data show that this is the case especially for bisexual males. Data on condom use show that the "AIDS era" left a strong impact on the population of homosexual men, who far more often use a condom in comparison with heterosexual and bisexual respondents.Izhodišča: V članku predstavljamo izsledke prve sociološke raziskave o spolnem vedenju uporabnikov interneta za internetne zmenke v Sloveniji s posebnim poudarkom na z zdravjem povezanih vidikih spolnega vedenja ljudi, ki se za zmenke dogovarjajo prek interneta. Metode: Vzorec predstavljajo uporabniki internetnih strani za spoznavanje partnerjev. Uporabili smo vzorčenje po metodi snežne kepe prek elektronske pošte in z objavo oglasa na portalih za spoznavanje partnerjev prek interneta. Podatki so bili zbrani v januarju in februarju 2007. Končni vzorec sestavlja 1.349 anketirancev. Rezultati: Večina anketirancev ni imela (44,2%) ali pa je imela majhno število spolnih partnerjev, ki so jih spoznali prek interneta (od 1 do 5 - 48%). Glede na spolno usmerjenost je imelo spolni odnos na prvem zmenku z osebo z interneta od 15 do 40% moških v primerjavi z od 7 do 18% žensk. Tretjina heteroseksualnih moških in žensk pri prvem spolnem odnosu z zadnjo osebo z interneta ni uporabila kondoma. Med uporabniki kondoma pri prvem spolnem odnosu z zadnjo osebo z interneta je največ homoseksualnih moških. Med njimi jih je 17% navedlo, da kondoma niso uporabili. Zaključki: Izsledki raziskave kažejo, da je čas od prvega on-line stika do prvega spolnega odnosa pomemben pokazatelj za zdravje potencialno rizičnega spolnega vedenja. Naši podatki kažejo, da to velja še posebej za biseksualno usmerjene moške. Podatki o uporabi kondoma kažejo, da je "obdobje aidsa" pustilo močen pečat na populacijo homoseksualnih moških, ki v daleč največji meri uporabljajo kondom v primerjavi s heteroseksualno in z biseksualno usmerjenimi anketiranci