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Khaled Khairy, William Lemon, Fernando Amat, Philipp J Keller
Mechanics plays a key role in the development of higher organisms. However, understanding this relationship is complicated by the difficulty of modeling the link between local forces generated at the subcellular level and deformations observed at the tissue and whole-embryo levels. Here we propose an approach first developed for lipid bilayers and cell membranes, in which force-generation by cytoskeletal elements enters a continuum mechanics formulation for the full system in the form of local changes in preferred curvature...
January 23, 2018: Biophysical Journal
Ece Durmusoglu, Onur Ugurlu, Sebnem Akan, Fatma Simsek, Gozde Kizilates, Omer Kitis, Burcu Aksoy Ozkul, Cagdas Eker, Kerry L Coburn, Ali Saffet Gonul
BACKGROUND: Although reduced hippocampal volume (HCV) is a common finding in depression, it is unclear whether the structural alterations leading to reduction of HCV are pre-existing risk factors before the onset of clinical symptoms or a cumulative process that begins with the onset of clinical symptoms. The aim of the present study was to understand the anatomical status of the hippocampus prior to the clinical symptoms in subjects with high familial risk for depression. METHODS: Twenty-seven young women (mean age: 22...
April 2018: Comprehensive Psychiatry
L R Gomes, L H Cevidanes, M R Gomes, A C Ruellas, D P Ryan, B Paniagua, L M Wolford, J R Gonçalves
This study investigated predictive risk factors of condylar remodeling changes after counterclockwise maxillomandibular advancement (CCW-MMA) and disc repositioning surgery. Forty-one female patients (75 condyles) treated with CCW-MMA and disc repositioning had cone beam computed tomography (CBCT) scans taken pre-surgery, immediately after surgery, and at an average 16 months post-surgery. Pre- and post-surgical three-dimensional models were superimposed using automated voxel-based registration on the cranial base to evaluate condylar displacements after surgery...
December 2017: International Journal of Oral and Maxillofacial Surgery
Sabrina B Sholts, Joseph A M Gingerich, Stefan Schlager, Dennis J Stanford, Sebastian K T S Wärmländer
Stone tools, often the sole remnant of prehistoric hunter-gatherer behavior, are frequently used as evidence of ancient human mobility, resource use, and environmental adaptation. In North America, studies of morphological variation in projectile points have provided important insights into migration and interactions of human groups as early as 12-13 kya. Using new approaches to 3D imaging and morphometric analysis, we here quantify bifacial asymmetry among early North American projectile point styles to better understand changes in knapping technique and cultural transmission...
2017: PloS One
Jinke Wang, Changfa Shi
BACKGROUND: In the active shape model framework, principal component analysis (PCA) based statistical shape models (SSMs) are widely employed to incorporate high-level a priori shape knowledge of the structure to be segmented to achieve robustness. A crucial component of building SSMs is to establish shape correspondence between all training shapes, which is a very challenging task, especially in three dimensions. METHODS: We propose a novel mesh-to-volume registration based shape correspondence establishment method to improve the accuracy and reduce the computational cost...
April 24, 2017: Biomedical Engineering Online
Richard Rios, Renaud De Crevoisier, Juan D Ospina, Frederic Commandeur, Caroline Lafond, Antoine Simon, Pascal Haigron, Jairo Espinosa, Oscar Acosta
In radiotherapy for prostate cancer irradiation of neighboring organs at risk may lead to undesirable side-effects. Given this setting, the bladder presents the largest inter-fraction shape variations hampering the computation of the actual delivered dose vs. planned dose. This paper proposes a population model, based on longitudinal data, able to estimate the probability of bladder presence during treatment, using only the planning computed tomography (CT) scan as input information. As in previously-proposed principal component analysis (PCA) population-based models, we have used the data to obtain the dominant eigenmodes that describe bladder geometric variations between fractions...
May 2017: Medical Image Analysis
Fatemeh Abdolali, Reza Aghaeizadeh Zoroofi, Yoshito Otake, Yoshinobu Sato
BACKGROUND AND OBJECTIVE: Accurate detection of maxillofacial cysts is an essential step for diagnosis, monitoring and planning therapeutic intervention. Cysts can be of various sizes and shapes and existing detection methods lead to poor results. Customizing automatic detection systems to gain sufficient accuracy in clinical practice is highly challenging. For this purpose, integrating the engineering knowledge in efficient feature extraction is essential. METHODS: This paper presents a novel framework for maxillofacial cysts detection...
February 2017: Computer Methods and Programs in Biomedicine
Hosung Kim, Ji-Hoon Kim, Katherine L Possin, Joseph Winer, Michael D Geschwind, Duan Xu, Christopher P Hess
In patients with premotor Huntington's disease (pmHD), literature has reported decreases in caudate volume. However, the regional vulnerability of the caudate nucleus to pmHD remains to be clarified. We aimed to determine whether regional structural damage of the caudate nucleus was present in pmHD and was correlated with clinical profile using a surface-based morphometric technique applied to T1-weighted MRI. The study cohort consisted of 14 volunteers with genetically confirmed pmHD (6 males; 41.8 ± 13...
October 2017: Brain Imaging and Behavior
Tung Nguyen, Ceib Phillips, Beatriz Paniagua
OBJECTIVE: To introduce new 3-D imaging techniques to characterize shape and volume changes of the oropharyngeal space after bilateral sagittal split osteotomy (BSSO) advancement. MATERIALS AND METHODS: Longitudinal cone-beam computed tomography (CBCT) scans were obtained for 20 patients undergoing BSSO advancement at three time points (T1 = presurgery, T2 = splint removal, and T3 = 1 year after surgery). Segmentation of the airway was performed using the following boundaries: hard palate/posterior nasal spine superiorly and lower border of C3 to the base of the epiglottis inferiorly...
November 2016: Angle Orthodontist
Liliane Rosas Gomes, Marcelo Regis Gomes, João Roberto Gonçalves, Antônio Carlos O Ruellas, Larry M Wolford, Beatriz Paniagua, Erika Benavides, Lúcia Helena Soares Cevidanes
OBJECTIVE: To quantitatively compare condylar morphology using cone beam computed tomography (CBCT) and multislice spiral computed tomography (MSCT) virtual three-dimensional surface models. STUDY DESIGN: The sample consisted of secondary data analyses of CBCT and MSCT scans obtained for clinical purposes from 74 patients treated with condylar resection and prosthetic joint replacement. Three-dimensional surface models of 146 condyles were constructed from each scan modality...
January 2016: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Alexandra Kammen, Meng Law, Bosco S Tjan, Arthur W Toga, Yonggang Shi
Diffusion MRI tractography provides a non-invasive modality to examine the human retinofugal projection, which consists of the optic nerves, optic chiasm, optic tracts, the lateral geniculate nuclei (LGN) and the optic radiations. However, the pathway has several anatomic features that make it particularly challenging to study with tractography, including its location near blood vessels and bone-air interface at the base of the cerebrum, crossing fibers at the chiasm, somewhat-tortuous course around the temporal horn via Meyer's Loop, and multiple closely neighboring fiber bundles...
January 15, 2016: NeuroImage
Aline M da S Braga, Elaine K Fujisao, Roberto C Verdade, Rômulo P Paschoalato, Ricardo P Paschoalato, Seizo Yamashita, Luiz E Betting
OBJECTIVE: Studies using quantitative neuroimaging have shown subtle abnormalities in patients with idiopathic generalized epilepsy (IGE). These findings have several locations, but the midline parasagittal structures are most commonly implicated. The cingulate cortex is related and may be involved. The objective of the current investigation was to perform a comprehensive analysis of the cingulate cortex using multiple quantitative structural neuroimaging techniques. METHODS: Thirty-two patients (18 women, 30 ± 10 years) and 36 controls (18 women, 32 ± 11 years) were imaged by 3 Tesla magnetic resonance imaging (MRI)...
November 2015: Epilepsia
Liliane R Gomes, Marcelo Gomes, Bryan Jung, Beatriz Paniagua, Antonio C Ruellas, João Roberto Gonçalves, Martin A Styner, Larry Wolford, Lucia Cevidanes
This study aimed to investigate imaging statistical approaches for classifying three-dimensional (3-D) osteoarthritic morphological variations among 169 temporomandibular joint (TMJ) condyles. Cone-beam computed tomography scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA), 15 subjects at initial diagnosis of OA, and 7 healthy controls. Three-dimensional surface models of the condyles were constructed and SPHARM-PDM established correspondent points on each model. Multivariate analysis of covariance and direction-projection-permutation (DiProPerm) were used for testing statistical significance of the differences between the groups determined by clinical and radiographic diagnoses...
July 2015: Journal of Medical Imaging
Matthew D Macfarlane, David Jakabek, Mark Walterfang, Susanna Vestberg, Dennis Velakoulis, Fiona A Wilkes, Christer Nilsson, Danielle van Westen, Jeffrey C L Looi, Alexander Frizell Santillo
INTRODUCTION: Behavioural variant frontotemporal dementia (bvFTD) is associated with changes in dorsal striatal parts of the basal ganglia (caudate nucleus and putamen), related to dysfunction in the cortico-striato-thalamic circuits which help mediate executive and motor functions. We aimed to determine whether the size and shape of striatal structures correlated with diagnosis of bvFTD, and measures of clinical severity, behaviour and cognition. MATERIALS AND METHODS: Magnetic resonance imaging scans from 28 patients with bvFTD and 26 healthy controls were manually traced using image analysis software (ITK-SNAP)...
2015: PloS One
A Pasha Hosseinbor, Moo K Chung, Cheng Guan Koay, Stacey M Schaefer, Carien M van Reekum, Lara Peschke Schmitz, Matt Sutterer, Andrew L Alexander, Richard J Davidson
Image-based parcellation of the brain often leads to multiple disconnected anatomical structures, which pose significant challenges for analyses of morphological shapes. Existing shape models, such as the widely used spherical harmonic (SPHARM) representation, assume topological invariance, so are unable to simultaneously parameterize multiple disjoint structures. In such a situation, SPHARM has to be applied separately to each individual structure. We present a novel surface parameterization technique using 4D hyperspherical harmonics in representing multiple disjoint objects as a single analytic function, terming it HyperSPHARM...
May 2015: Medical Image Analysis
Rosita Shishegar, Joanne M Britto, Leigh A Johnston
The cerebral cortex is folded into gyri and sulci in the brains of higher mammals. Quantitative study of the process by which the cortex folds during brain development is critical to a complete understanding of normal brain development and neuro-developmental disorders. In this work, we propose a new method by which to localise nonlinearities in the cortical folding process, and thereby identify regions of differential growth across the cortex. Our method is based on spherical harmonic (SPHARM) representation of the cortical surface...
2014: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Jaeil Kim, Maria Del C Valdes-Hernandez, Natalie A Royle, Jinah Park
Accurately recovering the hippocampal shapes against rough and noisy segmentations is as challenging as achieving good anatomical correspondence between the individual shapes. To address these issues, we propose a mesh-to-volume registration approach, characterized by a progressive model deformation. Our model implements flexible weighting scheme for model rigidity under a multi-level neighborhood for vertex connectivity. This method induces a large-to-small scale deformation of a template surface to build the pairwise correspondence by minimizing geometric distortion while robustly restoring the individuals' shape characteristics...
June 2015: IEEE Transactions on Medical Imaging
Shan Cong, Maher Rizkalla, Eliza Y Du, John West, Shannon Risacher, Andrew Saykin, Li Shen
The hippocampus is widely studied with neuroimaging techniques given its importance in learning and memory and its potential as a biomarker for brain disorders such as Alzheimer's disease and epilepsy. However, its complex folding anatomy often presents analytical challenges. In particular, the critical hippocampal subfield information is usually ignored by hippocampal registration in detailed morphometric studies. Such an approach is thus inadequate to accurately characterize hippocampal morphometry and effectively identify hippocampal structural changes related to different conditions...
August 2014: ... Midwest Symposium on Circuits and Systems Conference Proceedings: MWSCAS
Francesco Ciompi, Colin Jacobs, Ernst Th Scholten, Mathilde M W Wille, Pim A de Jong, Mathias Prokop, Bram van Ginneken
We present a novel descriptor for the characterization of pulmonary nodules in computed tomography (CT) images. The descriptor encodes information on nodule morphology and has scale-invariant and rotation-invariant properties. Information on nodule morphology is captured by sampling intensity profiles along circular patterns on spherical surfaces centered on the nodule, in a multi-scale fashion. Each intensity profile is interpreted as a periodic signal, where the Fourier transform is applied, obtaining a spectrum...
April 2015: IEEE Transactions on Medical Imaging
Ameer Pasha Hosseinbor, Won Hwa Kim, Nagesh Adluru, Amit Acharya, Houri K Vorperian, Moo K Chung
Recently, the HyperSPHARM algorithm was proposed to parameterize multiple disjoint objects in a holistic manner using the 4D hyperspherical harmonics. The HyperSPHARM coefficients are global; they cannot be used to directly infer localized variations in signal. In this paper, we present a unified wavelet framework that links Hyper-SPHARM to the diffusion wavelet transform. Specifically, we will show that the HyperSPHARM basis forms a subset of a wavelet-based multiscale representation of surface-based signals...
2014: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
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