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Computed Tomography Based Rigidity Analysis

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https://www.readbyqxmd.com/read/28506020/rigid-motion-artifact-reduction-in-ct-using-frequency-domain-analysis
#1
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...
May 6, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28490254/validating-dose-uncertainty-estimates-produced-by-autodirect-an-automated-program-to-evaluate-deformable-image-registration-accuracy
#2
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
https://www.readbyqxmd.com/read/28275526/quantifying-variability-in-longitudinal-peripapillary-rnfl-and-choroidal-layer-thickness-using-surface-based-registration-of-oct-images
#3
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
https://www.readbyqxmd.com/read/28242137/evaluation-of-a-multi-atlas-ct-synthesis-approach-for-mri-only-radiotherapy-treatment-planning
#4
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
https://www.readbyqxmd.com/read/28168813/the-impacts-of-mid-treatment-cbct-guided-patient-repositioning-on-target-coverage-during-lung-vmat
#5
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)...
February 7, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/28072574/motion-compensation-using-origin-ensembles-in-awake-small-animal-positron-emission-tomography
#6
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
https://www.readbyqxmd.com/read/28048870/su-f-j-81-evaluation-of-automated-deformable-registration-between-planning-computed-tomography-ct-and-daily-cone-beam-ct-images-over-the-course-of-prostate-cancer-radiotherapy
#7
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
https://www.readbyqxmd.com/read/28048110/su-f-j-102-lower-esophagus-margin-implications-based-on-rapid-computational-algorithm-for-sbrt
#8
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
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
#9
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
#10
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
https://www.readbyqxmd.com/read/27389943/a-comparison-of-accuracy-of-image-versus-hardware-based-tracking-technologies-in-3d-fusion-in-aortic-endografting
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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...
February 24, 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
#18
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
#19
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
#20
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
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