| 1. |
- Didziokas, Marius, et al.
(författare)
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BounTI (boundary-preserving threshold iteration): A user-friendly tool for automatic hard tissue segmentation
- 2024
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Ingår i: JOURNAL OF ANATOMY. - 0021-8782 .- 1469-7580.
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Tidskriftsartikel (refereegranskat)abstract
- X-ray Computed Tomography (CT) images are widely used in various fields of natural, physical, and biological sciences. 3D reconstruction of the images involves segmentation of the structures of interest. Manual segmentation has been widely used in the field of biological sciences for complex structures composed of several sub-parts and can be a time-consuming process. Many tools have been developed to automate the segmentation process, all with various limitations and advantages, however, multipart segmentation remains a largely manual process. The aim of this study was to develop an open-access and user-friendly tool for the automatic segmentation of calcified tissues, specifically focusing on craniofacial bones. Here we describe BounTI, a novel segmentation algorithm which preserves boundaries between separate segments through iterative thresholding. This study outlines the working principles behind this algorithm, investigates the effect of several input parameters on its outcome, and then tests its versatility on CT images of the craniofacial system from different species (e.g. a snake, a lizard, an amphibian, a mouse and a human skull) with various scan qualities. The case studies demonstrate that this algorithm can be effectively used to segment the craniofacial system of a range of species automatically. High-resolution microCT images resulted in more accurate boundary-preserved segmentation, nonetheless significantly lower-quality clinical images could still be segmented using the proposed algorithm. Methods for manual intervention are included in this tool when the scan quality is insufficient to achieve the desired segmentation results. While the focus here was on the craniofacial system, BounTI can be used to automatically segment any hard tissue. The tool presented here is available as an Avizo/Amira add-on, a stand-alone Windows executable, and a Python library. We believe this accessible and user-friendly segmentation tool can benefit the wider anatomical community.
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| 2. |
- Haber, Samer E., et al.
(författare)
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Secondary Le Fort III after Early Fronto-Facial Monobloc Normalizes Sleep Apnea in Faciocraniosynostosis : A Cohort Study
- 2022
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Ingår i: Journal of Plastic, Reconstructive & Aesthetic Surgery. - : Elsevier. - 1748-6815 .- 1878-0539. ; 75:8, s. 2706-2718
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study aims to assess the improvement of sleep apnea after sec-ondary Le Fort III facial advancement with distraction (LF3) in faciocraniosynostosis (FCS) pa-tients with sleep apnea who have previously undergone fronto-facial monobloc advancement (FFMBA) with distraction.Methods: Patients having undergone secondary LF3 were selected from a cohort of FCS pa-tients with documented sleep apnea who had previously undergone fronto-facial monobloc advancement. Patient charts and polysomnographic records were reviewed. Apnea-hypopnea index (AHI) was recorded before and at least 6 months after secondary LF3. The primary out-come was normalization of AHI (less than 5/h was considered normal). Hierarchical multilevel analysis was performed to predict postoperative AHI evolution.Results: Seventeen patients underwent a secondary LF3, 7.0 +/- 3.9 years after the primary FFMBA. The mean age was 9.6 +/- 3.9 years. A total of 15 patients (88%) normalized their AHI. Two of four patients were decannulated (50%). There was a statistically significant decrease in AHI (preoperative AHI 21.5/h vs. 3.9/h postoperatively, p = 0.003). Hierarchic multilevel mod-eling showed progressive AHI decrease postoperatively.Conclusion: Secondary LF3 improves residual or relapsing sleep apnea in FCS patients who have previously had FFMBA.
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| 3. |
- Khonsari, Roman H., et al.
(författare)
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Fronto-facial advancement and bipartition in Crouzon-Pfeiffer and Apert syndromes : Impact of fronto-facial surgery upon orbital and airway parameters in FGFR2 syndromes
- 2016
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : Elsevier BV. - 1010-5182 .- 1878-4119. ; 44:10, s. 1567-1575
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Tidskriftsartikel (refereegranskat)abstract
- A major concern in FGFR2 craniofaciosynostosis is oculo-orbital disproportion, such that orbital malformation provides poor accommodation and support for the orbital contents and peri-orbita, leading to insufficient eyelid closure, corneal exposure and eventually to functional visual impairment. Fronto-facial monobloc osteotomy followed by distraction osteogenesis aims to correct midfacial growth deficiencies in Crouzon–Pfeiffer syndrome patients. Fronto-facial bipartition osteotomy followed by distraction is a procedure of choice in Apert syndrome patients. These procedures modify the shape and volume of the orbit and tend to correct oculo-orbital disproportion. Little is known about the detailed 3D shape of the orbital phenotype in CPS and AS, and about how this is modified by fronto-facial surgery.Twenty-eight patients with CMS, 13 patients with AS and 40 control patients were included. CT scans were performed before and after fronto-facial surgery. Late post-operative scans were available for the Crouzon–Pfeiffer syndrome group. Orbital morphology was investigated using conventional three-dimensional cephalometry and shape analysis after mesh-based segmentation of the orbital contents.We characterized the 3D morphology of CPS and AS orbits and showed how orbital shape is modified by surgery. We showed that monobloc-distraction in CPS and bipartition-distraction in AS specifically address the morphological characteristics of the two syndromes.
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| 4. |
- Levasseur, Julie, et al.
(författare)
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Orbital volume and shape in Treacher Collins syndrome
- 2018
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : CHURCHILL LIVINGSTONE. - 1010-5182 .- 1878-4119. ; 46:2, s. 305-311
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Tidskriftsartikel (refereegranskat)abstract
- Orbito-palpebral reconstruction is a challenge in Treacher Collins syndrome (TCS). This study investigates orbital phenotypes in TCS using cephalometry and orbital shape analysis. Eighteen TCS and 52 control patients were included in this study, using the Dr Warehouse database. Orbital cephalometry was based on 20 landmarks, 10 planes, 16 angles, and 22 distances. Orbits were segmented. Registration-based, age-specific mean models were generated using semi-automatic segmentation, and aligned and compared using color-coded distance maps - mean absolute distance (MAD), Hausdorff distance (HD), and Dice similarity coefficient (DSC). Symmetry was assessed by mirroring and DSC computing. Central orbital depth ( COD) and medial orbital depth ( MOD) allowed 100% of orbits to be classified. COD and lateral orbital depth (LOD) were different from the controls. Average MAD between TCS and controls was <= 1.5 mm, while for HD it was > 1.5 mm, and for DSC <1. TCS orbits were more asymmetrical than controls, and orbital volumes were smaller when age was considered as a confounding factor, and had a trend for normalization with age. This report emphasizes the importance of combining different morphometric approaches in the phenotype characterization of non-trivial structures such as the orbit, and supports composite skeletal and soft-tissue strategies for the management of the peri-orbital region.
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