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Computed Tomography Based Rigidity Analysis

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https://www.readbyqxmd.com/read/27585495/curved-beam-computed-tomography-based-structural-rigidity-analysis-of-bones-with-simulated-lytic-defect-a-comparative-study-with-finite-element-analysis
#1
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
https://www.readbyqxmd.com/read/27577868/schneider-membrane-thickness-classification-evaluated-by-cone-beam-computed-tomography-and-its-importance-in-the-predictability-of-perforation-retrospective-analysis-of-200-patients
#2
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...
August 27, 2016: British Journal of Oral & Maxillofacial Surgery
https://www.readbyqxmd.com/read/27389943/a-comparison-of-accuracy-of-image-versus-hardware-based-tracking-technologies-in-3d-fusion-in-aortic-endografting
#3
COMMENT
A E Rolls, B Maurel, M Davis, J Constantinou, G Hamilton, T M Mastracci
OBJECTIVES: Fusion of three-dimensional (3D) computed tomography and intraoperative two-dimensional imaging in endovascular surgery relies on manual rigid co-registration of bony landmarks and tracking of hardware to provide a 3D overlay (hardware-based tracking, HWT). An alternative technique (image-based tracking, IMT) uses image recognition to register and place the fusion mask. We present preliminary experience with an agnostic fusion technology that uses IMT, with the aim of comparing the accuracy of overlay for this technology with HWT...
September 2016: European Journal of Vascular and Endovascular Surgery
https://www.readbyqxmd.com/read/27260559/noninvasive-failure-load-prediction-of-vertebrae-with-simulated-lytic-defects-and-biomaterial-augmentation
#4
Hugo Giambini, Zhong Fang, Heng Zeng, Jon J Camp, Michael J Yaszemski, Lichun Lu
The spine is the most common site for secondary bone metastases, and clinical management for fractures is based on size and geometry of the defect. About 75% of the bone needs to be damaged before lesions are detectable, so clinical tools should measure changes in both geometry and material properties. We have developed an automated, user-friendly, Spine Cancer Assessment (SCA) image-based analysis method that builds on a platform designed for clinical practice providing failure characteristics of vertebrae...
August 2016: Tissue Engineering. Part C, Methods
https://www.readbyqxmd.com/read/27209500/image-guided-radiation-therapy-using-synthetic-computed-tomography-images-in-brain-cancer
#5
Ryan G Price, Joshua P Kim, Weili Zheng, Indrin J Chetty, Carri Glide-Hurst
PURPOSE: The development of synthetic computed tomography (CT) (synCT) derived from magnetic resonance (MR) images supports MR-only treatment planning. We evaluated the accuracy of synCT and synCT-generated digitally reconstructed radiographs (DRRs) relative to CT and determined their performance for image guided radiation therapy (IGRT). METHODS AND MATERIALS: Magnetic resonance simulation (MR-SIM) and CT simulation (CT-SIM) images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases...
July 15, 2016: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/27195001/brain-perfusion-in-corticobasal-syndrome-with-progressive-aphasia
#6
Yoshitake Abe, Noriyuki Kimura, Megumi Goto, Yasuhiro Aso, Etsuro Matsubara
BACKGROUND: Brain perfusion may differ between patients with corticobasal syndrome (CBS) with and without aphasia. METHODS: Twenty-six (9 males and 17 females; mean age 76 ± 5.3 years) patients with CBS were enrolled in the study. Brain MRI and single-photon emission computed tomography were performed in all subjects. Language was evaluated using the Standard Language Test of Aphasia. The patients were divided into two subgroups according to the presence or absence of progressive aphasia...
January 2016: Dementia and Geriatric Cognitive Disorders Extra
https://www.readbyqxmd.com/read/27178768/predictors-of-reduction-loss-in-tibial-plateau-fracture-surgery-focusing-on-posterior-coronal-fractures
#7
Chang-Wan Kim, Chang-Rack Lee, Ki-Chan An, Heui-Chul Gwak, Jung-Han Kim, Lih Wang, Dong-Gil Yoon
INTRODUCTION: Some studies have reported that fracture pattern was associated with reduction loss after surgery. The purpose of this study was to evaluate various factors that can influence reduction loss, including fracture patterns in unicondylar and bicondylar tibial plateau fractures. MATERIALS AND METHODS: A total of 138 tibial plateau fractures that underwent open reduction and internal fixation using plates were retrospectively reviewed. The OTA/AO classification, fracture pattern, degree of comminution, and existence of reduction loss were evaluated based on simple radiographs and computed tomography...
July 2016: Injury
https://www.readbyqxmd.com/read/27061797/analysis-of-the-setup-errors-of-medical-image-registration-based-cone-beam-ct-for-lung-cancer
#8
Jun Li, Xiao-Bin Tang, Xi-Zhi Zhang, Xian-Wen Zhang, Yun Ge, Da Chen, Lei Chai
PURPOSE: This study aimed to investigate the feasibility of efficiently using a rigid image registration (RIR) algorithm or a deformable image registration (DIR) algorithm to match medical images and evaluate the impact of setup errors on intensity modulated radiation therapy of lung cancer patients. METHODS: Ten lung cancer patients were chosen randomly each day and were subjected to image-guided radiotherapy. The clinical registration between cone-beam computed tomography (CBCT) images and treatment planning system CT images was performed by applying both RIR and DIR; the clinical registration was evaluated on the basis of the contour index, including dice similarity coefficient, sensitivity, and positive predictive value; the optimal scheme of image registration was selected to ensure that the actual irradiation isocenter was consistent with the treatment planning isocenter...
April 7, 2016: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/26911571/a-ct-method-for-following-patients-with-both-prosthetic-replacement-and-implanted-tantalum-beads-preliminary-analysis-with-a-pelvic-model-and-in-seven-patients
#9
Henrik Olivecrona, Gerald Q Maguire, Marilyn E Noz, Michael P Zeleznik, Uldis Kesteris, Lars Weidenhielm
BACKGROUND: Radiostereometric analysis (RSA) is often used for evaluating implanted devices over time. Following patients who have had tantalum beads implanted as markers in conjunction with joint replacements is important for longitudinal evaluation of these patients and for those with similar implants. As doing traditional RSA imaging is exacting and limited to specialized centers, it is important to consider alternative techniques for this ongoing evaluation. This paper studies the use of computed tomography (CT) to evaluate over time tantalum beads which have been implanted as markers...
2016: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/26785845/3d-finite-element-model-of-the-chinchilla-ear-for-characterizing-middle-ear-functions
#10
Xuelin Wang, Rong Z Gan
Chinchilla is a commonly used animal model for research of sound transmission through the ear. Experimental measurements of the middle ear transfer function in chinchillas have shown that the middle ear cavity greatly affects the tympanic membrane (TM) and stapes footplate (FP) displacements. However, there is no finite element (FE) model of the chinchilla ear available in the literature to characterize the middle ear functions with the anatomical features of the chinchilla ear. This paper reports a recently completed 3D FE model of the chinchilla ear based on X-ray micro-computed tomography images of a chinchilla bulla...
October 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/26717197/geometric-validation-of-mv-topograms-for-patient-localization-on-tomotherapy
#11
Janid P Blanco Kiely, Benjamin M White, Daniel A Low, Sharon X Qi
Our goal was to geometrically validate the use of mega-voltage orthogonal scout images (MV topograms) as a fast and low-dose alternative to mega-voltage computed tomography (MVCT) for daily patient localization on the TomoTherapy system. To achieve this, anthropomorphic head and pelvis phantoms were imaged on a 16-slice kilo-voltage computed tomography (kVCT) scanner to synthesize kilo-voltage digitally reconstructed topograms (kV-DRT) in the Tomotherapy detector geometry. MV topograms were generated for couch speeds of 1-4 cm s(-1) in 1 cm s(-1) increments with static gantry angles in the anterior-posterior and left-lateral directions...
January 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/26531324/sensitivity-of-tumor-motion-simulation-accuracy-to-lung-biomechanical-modeling-approaches-and-parameters
#12
Joubin Nasehi Tehrani, Yin Yang, Rene Werner, Wei Lu, Daniel Low, Xiaohu Guo, Jing Wang
Finite element analysis (FEA)-based biomechanical modeling can be used to predict lung respiratory motion. In this technique, elastic models and biomechanical parameters are two important factors that determine modeling accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical modeling approaches and related parameters to improve the accuracy of motion simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT)...
November 21, 2015: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/26503671/hepatic-reaction-dose-for-parenchymal-changes-on-gd-eob-dtpa-enhanced-magnetic-resonance-images-after-stereotactic-body-radiation-therapy-for-hepatocellular-carcinoma
#13
Jinhong Jung, Sang Min Yoon, Byungchul Cho, Young Eun Choi, Jungwon Kwak, So Yeon Kim, Sang-Wook Lee, Seung Do Ahn, Eun Kyung Choi, Jong Hoon Kim
INTRODUCTION: The present study evaluated the threshold dose for hepatic parenchymal changes on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images after stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC). METHODS: Twenty patients with available data of follow-up MR images acquired 2-4 months after completion of SBRT were selected among the registered patients. SBRT was performed using multiple coplanar and non-coplanar beams with energies of 6 or 15 MV...
February 2016: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/26441413/improving-the-accuracy-of-registration-based-biomechanical-analysis-a-finite-element-approach-to-lung-regional-strain-quantification
#14
Daniel E Hurtado, Nicolas Villarroel, Jaime Retamal, Guillermo Bugedo, Alejandro Bruhn
Tissue deformation plays an important role in lung physiology, as lung parenchyma largely deforms during spontaneous ventilation. However, excessive regional deformation may lead to lung injury, as observed in patients undergoing mechanical ventilation. Thus, the accurate estimation of regional strain has recently received great attention in the intensive care community. In this work, we assess the accuracy of regional strain maps computed from direct differentiation of B-Spline (BS) interpolations, a popular technique employed in non-rigid registration of lung computed tomography (CT) images...
February 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/26364886/tumour-delineation-in-oesophageal-cancer-a-prospective-study-of-delineation-in-pet-and-ct-with-and-without-endoscopically-placed-clip-markers
#15
Lena Thomas, Constatin Lapa, Ralph Alexander Bundschuh, Bülent Polat, Jan-Jakob Sonke, Matthias Guckenberger
PURPOSE: The objective was to analyse the value of F-18-fluorodesoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) for delineation of the Gross Tumour Volumes (GTVs) in primary radiotherapy of oesophageal cancer. METHOD: 20 consecutive and prospective patients (13 men, 7 women) underwent FDG-PET/CT for initial staging and radiation treatment planning. After endoscopy-guided clipping of the tumour another CT study was acquired. The CT and the FDG-PET/CT were registered with a rigid and a non-rigid registration algorithm to compare the overlap between GTV contours defined with the following methods: manual GTV definition in (1) the CT image of the FDG-PET/CT, (2) the PET image of the FDG-PET/CT, (3) the CT study based on endoscopic clips (CT clip), and (4) in the PET-data using different semi-automatic PET segmentation algorithms including a gradient-based algorithm...
August 2015: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/26171793/evaluation-of-occipitocervical-arthrodesis-rates-with-screw-based-fixation-and-osteoinductive-fusion-adjuncts
#16
Jeremy G Stone, David M Panczykowski, Zachary J Tempel, Matthew Tormenti, Adam S Kanter, David O Okonkwo
Occipitocervical (OC) instability may be associated with neurologic impairment and even death. There is a paucity of research on the rate of arthrodesis utilizing modern screw-based constructs coupled with adjuvant osteoinductive agents. We reviewed our experience with OC constructs and compared the fusion rate, functional outcome, and rate of adverse events between recombinant human bone morphogenetic protein (BMP)-2, autologous iliac crest bone graft (ICBG), a combination of BMP and ICBG, and local bone autograft alone...
September 2015: Journal of Neurological Surgery. Part A, Central European Neurosurgery
https://www.readbyqxmd.com/read/25972933/quantitative-and-qualitative-analysis-of-the-working-area-obtained-by-endoscope-and-microscope-in-pterional-and-orbitozigomatic-approach-to-the-basilar-artery-bifurcation-using-computed-tomography-based-frameless-stereotaxy-a-cadaver-study
#17
Venko Filipce, Mario Ammirati
OBJECTIVE: Basilar aneurisms are one of the most complex and challenging pathologies for neurosurgeons to treat. Endoscopy is a recently rediscovered neurosurgical technique that could lend itself well to overcome some of the vascular visualization challenges associated with this pathology. The purpose of this study was to quantify and compare the basilar artery (BA) bifurcation (tip of the basilar) working area afforded by the microscope and the endoscope using different approaches and image guidance...
April 2015: Asian Journal of Neurosurgery
https://www.readbyqxmd.com/read/25890308/development-of-cbct-based-prostate-setup-correction-strategies-and-impact-of-rectal-distension
#18
Christine Boydev, Abdelmalik Taleb-Ahmed, Foued Derraz, Laurent Peyrodie, Jean-Philippe Thiran, David Pasquier
BACKGROUND: Cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT) systems are widely used tools to verify and correct the target position before each fraction, allowing to maximize treatment accuracy and precision. In this study, we evaluate automatic three-dimensional intensity-based rigid registration (RR) methods for prostate setup correction using CBCT scans and study the impact of rectal distension on registration quality. METHODS: We retrospectively analyzed 115 CBCT scans of 10 prostate patients...
April 10, 2015: Radiation Oncology
https://www.readbyqxmd.com/read/25881252/aortic-dissection-simulation-models-for-clinical-support-fluid-structure-interaction-vs-rigid-wall-models
#19
Mona Alimohammadi, Joseph M Sherwood, Morad Karimpour, Obiekezie Agu, Stavroula Balabani, Vanessa Díaz-Zuccarini
BACKGROUND: The management and prognosis of aortic dissection (AD) is often challenging and the use of personalised computational models is being explored as a tool to improve clinical outcome. Including vessel wall motion in such simulations can provide more realistic and potentially accurate results, but requires significant additional computational resources, as well as expertise. With clinical translation as the final aim, trade-offs between complexity, speed and accuracy are inevitable...
2015: Biomedical Engineering Online
https://www.readbyqxmd.com/read/25585851/assessment-of-operability-by-means-of-ctpa-and-perfusion-spect-in-patients-with-chronic-thromboembolic-pulmonary-hypertension
#20
Aleksandar Grgic, Florian Miodek, Hans-Joachim Schäfers, Matthias Held, Ralf Kaiser, Fadi Khreish, Arno Buecker, Robert Bals, Carl-Martin Kirsch, Heinrike Wilkens
BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) can potentially be cured by pulmonary thrombendarterectomy (PEA), the criteria for differentiation between operable and non-operable patients are not standardized. PURPOSE: To retrospectively evaluate the value of rigidly registered computed tomography pulmonary angiography (CTPA) and single photon emission CT (SPECT) in differentiating for PEA. MATERIAL AND METHODS: Forty-nine patients with CTEPH (21 men; age, 58 ± 13 years) were evaluated by an interdisciplinary expert board using all available diagnostic information and their consensus statement as gold standard...
January 2016: Acta Radiologica
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