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Computed Tomography Based Rigidity Analysis

Vimal Chandran, Mauricio Reyes, Philippe Zysset
Osteoporosis leads to hip fractures in aging populations and is diagnosed by modern medical imaging techniques such as quantitative computed tomography (QCT). Hip fracture sites involve trabecular bone, whose strength is determined by volume fraction and orientation, known as fabric. However, bone fabric cannot be reliably assessed in clinical QCT images of proximal femur. Accordingly, we propose a novel registration-based estimation of bone fabric designed to preserve tensor properties of bone fabric and to map bone fabric by a global and local decomposition of the gradient of a non-rigid image registration transformation...
2017: PloS One
Ki-Sun Lee, Sang-Wan Shin, Sang-Pyo Lee, Jong-Eun Kim, Jee-Hwan Kim, Jeong-Yol Lee
PURPOSE: The purpose of this pilot study was to evaluate and compare polyetherketoneketone (PEKK) with different framework materials for implant-supported prostheses by means of a three-dimensional finite element analysis (3D-FEA) based on cone beam computed tomography (CBCT) and computer-aided design (CAD) data. MATERIALS AND METHODS: A geometric model that consisted of four maxillary implants supporting a prosthesis framework was constructed from CBCT and CAD data of a treated patient...
November 2017: International Journal of Prosthodontics
Louis M Metcalf, Enrico Dall'Ara, Margaret A Paggiosi, John R Rochester, Nicolas Vilayphiou, Graham J Kemp, Eugene V McCloskey
OBJECTIVE: Assessment of calcaneus microstructure using high-resolution peripheral quantitative computed tomography (HR-pQCT) might be used to improve fracture risk predictions or to assess responses to pharmacological and physical interventions. To develop a standard clinical protocol for the calcaneus, we validated calcaneus trabecular microstructure measured by HR-pQCT against 'gold-standard' micro-CT measurements. METHODS: Ten human cadaveric feet were scanned in situ using HR-pQCT (isotropic 82μm voxel size) at 100, 150 and 200ms integration times, and at 100ms integration time following removal of the calcaneus from the foot (ex vivo)...
October 3, 2017: Bone
Masafumi Kidoh, Daisuke Utsunomiya, Yoshinori Funama, Hiroshi Ashikaga, Takeshi Nakaura, Seitaro Oda, Hideaki Yuki, Kenichiro Hirata, Yuji Iyama, Yasunori Nagayama, Toshihiro Fukui, Yasuyuki Yamashita, Katsuyuki Taguchi
BACKGROUND: Cardiac computed tomography (CT) has the potential for fully four-dimensional (4D for 3D plus time) motion analysis of the heart. We aimed at developing a method for assessment and presentation of the 4D motion for multi-phase, contrast-enhanced cardiac CT data sets and demonstrating its clinical applicability. METHODS: Four patients with normal cardiac function, old myocardial infarction (OMI), takotsubo cardiomyopathy, and hypertrophic cardiomyopathy (HCM) underwent contrast-enhanced cardiac CT for one heartbeat using a 320-row CT scanner with no tube current modulation...
November 2017: Journal of Cardiovascular Computed Tomography
E Šťastný, T Trč, J Frýdl, Z Kopečný, T Philippou, J Lisý
INTRODUCTION The purpose of our paper is to evaluate the mid-term to long-term results and to confirm the basic criteria of a high-quality revision implant: safe bridging of bone defects, achievement of reliable primary fixation of revision acetabular cup, achievement of good secondary stability with documentable osteointegration of cup and demonstration of remodelling of transplanted bone tissue in the area of defects and in spaces between the implant ribs. MATERIAL AND METHODS Altogether 36 patients (38 cups) were evaluated who had undergone revision hip arthroplasty in the period from 2004 to 2010...
2017: Acta Chirurgiae Orthopaedicae et Traumatologiae Cechoslovaca
Eleni Metaxa, Konstantinos Tzirakis, Nikolaos Kontopodis, Christos V Ioannou, Yannis Papaharilaou
BACKGROUND: The natural history of abdominal aortic aneurysm (AAA) can be investigated through longitudinal evaluation of localized aneurysm characteristics exploiting clinical images. The major challenge is to identify corresponding regions between follow-ups. We have recently developed an algorithm (VascForm) based on nonrigid registration that can obtain surface correspondence and quantify surface growth distribution. METHODS: A ruptured AAA with an initial computed tomography scan 2 years ago was studied...
January 2018: Annals of Vascular Surgery
Johannes Müller, Christian Neubert, Cläre von Neubeck, Michael Baumann, Mechthild Krause, Wolfgang Enghardt, Rebecca Bütof, Antje Dietrich, Armin Lühr
INTRODUCTION: As proton therapy becomes increasingly well established, there is a need for high-quality clinically relevant in vivo data to gain better insight into the radiobiological effects of proton irradiation on both healthy and tumor tissue. This requires the development of easily applicable setups that allow for efficient, fractionated, image-guided proton irradiation of small animals, the most widely used pre-clinical model. MATERIAL AND METHODS: Here, a method is proposed to perform dual-energy proton radiography for inline positioning verification and treatment planning...
November 2017: Acta Oncologica
Delia Ciardo, Barbara Alicja Jereczek-Fossa, Giuseppe Petralia, Giorgia Timon, Dario Zerini, Raffaella Cambria, Elena Rondi, Federica Cattani, Alessia Bazani, Rosalinda Ricotti, Maria Garioni, Davide Maestri, Giulia Marvaso, Paola Romanelli, Marco Riboldi, Guido Baroni, Roberto Orecchia
PURPOSE: The integration of CT and multiparametric MRI (mpMRI) is a challenging task in high-precision radiotherapy for prostate cancer. A simple methodology for multimodal deformable image registration (DIR) of prostate cancer patients is presented. METHODS: CT and mpMRI of 10 patients were considered. Organs at risk and prostate were contoured on both scans. The dominant intraprostatic lesion was additionally delineated on MRI. After a preliminary rigid image registration, the voxel intensity of all the segmented structures in both scans except the prostate was increased by a specific amount (a constant additional value, A), in order to enhance the contrast of the main organs influencing its position and shape...
November 2017: British Journal of Radiology
Joost J A de Jong, Patrik Christen, Ryan M Plett, Roland Chapurlat, Piet P Geusens, Joop P W van den Bergh, Ralph Müller, Bert van Rietbergen
For accurate analysis of bone formation and resorption during fracture healing, correct registration of follow-up onto baseline image is required. A per-fragment approach could improve alignment compared to standard registration based on the whole fractured region. In this exploratory study, we tested the effect of fragment size and displacement on a per-fragment registration, and compared the results of this per-fragment registration to the results of the standard registration in two stable fractures and one unstable fracture...
2017: PloS One
Gaetano Barbagallo, Maria Eugenia Caligiuri, Gennarina Arabia, Andrea Cherubini, Angela Lupo, Rita Nisticò, Maria Salsone, Fabiana Novellino, Maurizio Morelli, Giuseppe Lucio Cascini, Domenico Galea, Aldo Quattrone
Motor phenotypes of Parkinson's disease (PD) are recognized to have different prognosis and therapeutic response, but the neural basis for this clinical heterogeneity remains largely unknown. The main aim of this study was to compare differences in structural connectivity metrics of the main motor network between tremor-dominant and nontremor PD phenotypes (TD-PD and NT-PD, respectively) using probabilistic tractography-based network analysis. A total of 63 PD patients (35 TD-PD patients and 28 NT-PD patients) and 30 healthy controls underwent a 3 T MRI...
September 2017: Human Brain Mapping
Yuan Zhang, Liyi Zhang, Yunshan Sun
BACKGROUND: It is often unrealistic to assume that the subject remains stationary during a computed tomography (CT) imaging scan. A patient rigid motion can be decomposed into a translation and a rotation around an origin. How to minimize the motion impact on image quality is important. OBJECTIVE: To eliminate artifacts caused by patient rigid motion during a CT scan, this study investigated a new method based on frequency domain analysis to estimate and compensate motion impact...
2017: Journal of X-ray Science and Technology
Hojin Kim, Josephine Chen, Justin Phillips, Jason Pukala, Sue S Yom, Neil Kirby
Deformable image registration is a powerful tool for mapping information, such as radiation therapy dose calculations, from one computed tomography image to another. However, deformable image registration is susceptible to mapping errors. Recently, an automated deformable image registration evaluation of confidence tool was proposed to predict voxel-specific deformable image registration dose mapping errors on a patient-by-patient basis. The purpose of this work is to conduct an extensive analysis of automated deformable image registration evaluation of confidence tool to show its effectiveness in estimating dose mapping errors...
January 1, 2017: Technology in Cancer Research & Treatment
Sieun Lee, Morgan Heisler, Paul J Mackenzie, Marinko V Sarunic, Mirza Faisal Beg
PURPOSE: To assess within-subject variability of retinal nerve fiber layer (RNFL) and choroidal layer thickness in longitudinal repeat optical coherence tomography (OCT) images with point-to-point measurement comparison made using nonrigid surface registration. METHODS: Nine repeat peripapillary OCT images were acquired over 3 weeks from 12 eyes of 6 young, healthy subjects using a 1060-nm prototype swept-source device. The RNFL, choroid and the Bruch's membrane opening (BMO) were segmented, and point-wise layer thicknesses and BMO dimensions were measured...
February 2017: Translational Vision Science & Technology
F Guerreiro, N Burgos, A Dunlop, K Wong, I Petkar, C Nutting, K Harrington, S Bhide, K Newbold, D Dearnaley, N M deSouza, V A Morgan, J McClelland, S Nill, M J Cardoso, S Ourselin, U Oelfke, A C Knopf
BACKGROUND AND PURPOSE: Computed tomography (CT) imaging is the current gold standard for radiotherapy treatment planning (RTP). The establishment of a magnetic resonance imaging (MRI) only RTP workflow requires the generation of a synthetic CT (sCT) for dose calculation. This study evaluates the feasibility of using a multi-atlas sCT synthesis approach (sCTa) for head and neck and prostate patients. MATERIAL AND METHODS: The multi-atlas method was based on pairs of non-rigidly aligned MR and CT images...
March 2017: Physica Medica: PM
Dominique Mathieu, Marie-Pierre Campeau, Stéphane Bedwani, David Roberge, Robert Doucet, Karim Zerouali, Houda Bahig, Toni Vu, Louise Lambert, Laura Masucci, Edith Filion
INTRODUCTION: The purpose of this study is quantify intrafraction motion (IFM) during lung volumetric-modulated arc therapy (VMAT) and evaluate the impact of mid-treatment cone beam computed tomography (CBCT)-guided patient repositioning on target coverage. METHOD: This analysis included lung tumours treated with VMAT to 50-60 Gy in 3-5 fractions. Treatment planning was based on four-dimensional CT scans from which internal tumour volumes (ITV) were derived. An isotropic 5 mm margin was added to obtain the final planning target volume (PTV)...
August 2017: Journal of Medical Imaging and Radiation Oncology
John E Gillam, Georgios I Angelis, Andre Z Kyme, Steven R Meikle
In emission tomographic imaging, the stochastic origin ensembles algorithm provides unique information regarding the detected counts given the measured data. Precision in both voxel and region-wise parameters may be determined for a single data set based on the posterior distribution of the count density allowing uncertainty estimates to be allocated to quantitative measures. Uncertainty estimates are of particular importance in awake animal neurological and behavioral studies for which head motion, unique for each acquired data set, perturbs the measured data...
February 7, 2017: Physics in Medicine and Biology
J Matney, J Hammers, O Kaidar-Person, A Wang, R Chen, S Das, L Marks, P Mavroidis
PURPOSE: To compute daily dose delivered during radiotherapy, deformable registration needs to be relatively fast, automated, and accurate. The aim of this study was to evaluate the performance of commercial deformable registration software for deforming between two modalities: planning computed tomography (pCT) images acquired for treatment planning and cone beam (CB) CT images acquired prior to each fraction of prostate cancer radiotherapy. METHODS: A workflow was designed using MIM Software™ that aligned and deformed pCT into daily CBCT images in two steps: (1) rigid shifts applied after daily CBCT imaging to align patient anatomy to the pCT and (2) normalized intensity-based deformable registration to account for interfractional anatomical variations...
June 2016: Medical Physics
M Cardenas, T Mazur, H Li, S Mutic, J Bradley, C Tsien, O Green
PURPOSE: To quantify inter-fraction esophagus-variation. METHODS: Computed tomography and daily on-treatment 0.3-T MRI data sets for 7 patients were analyzed using a novel Matlab-based (Mathworks, Natick, MA) rapid computational method. Rigid registration was performed from the cricoid to the gastro-esophageal junction. CT and MR-based contours were compared at slice intervals of 3mm. Variation was quantified by "expansion," defined as additional length in any radial direction from CT contour to MR contour...
June 2016: Medical Physics
R Oftadeh, Z Karimi, J Villa-Camacho, E Tanck, N Verdonschot, R Goebel, B D Snyder, H N Hashemi, A Vaziri, A Nazarian
In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections...
September 2, 2016: Scientific Reports
M Rapani, C Rapani, L Ricci
Perforation of the Schneiderian membrane is a common complication of sinus augmentation. The aim of this retrospective study was to assess the associations between the lateral wall technique and the ridge approach and the risk of perforation, together with the relations between the thickness of the membrane and the risk of perforation. We studied 200 patients (103 men and 97 women) who had cone-beam computed tomography (CT) before a sinus lift with either a lateral wall technique (n=100) or the rigid approach (n=100) for insertion of prosthetic implants...
December 2016: British Journal of Oral & Maxillofacial Surgery
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