keyword
MENU ▼
Read by QxMD icon Read
search

4D CT

keyword
https://www.readbyqxmd.com/read/29772057/a-4d-global-respiratory-motion-model-of-the-thorax-based-on-ct-images-a-proof-of-concept
#1
H Fayad, M Gilles, T Pan, D Visvikis
PURPOSE: Respiratory motion reduces the sensitivity and specificity of medical images especially in the thoracic and abdominal areas. It may affect applications such as cancer diagnostic imaging and/or radiation therapy (RT). Solutions to this issue include modelling of the respiratory motion in order to optimize both diagnostic and therapeutic protocols. Personalised motion modeling required patient specific four dimensional (4D) imaging which in the case of 4D computed tomography (4D CT) acquisition is associated with an increased dose...
May 17, 2018: Medical Physics
https://www.readbyqxmd.com/read/29769576/motion-compensated-micro-ct-reconstruction-for-in-situ-analysis-of-dynamic-processes
#2
Thomas De Schryver, Manuel Dierick, Marjolein Heyndrickx, Jeroen Van Stappen, Marijn A Boone, Luc Van Hoorebeke, Matthieu N Boone
This work presents a framework to exploit the synergy between Digital Volume Correlation (DVC) and iterative CT reconstruction to enhance the quality of high-resolution dynamic X-ray CT (4D-µCT) and obtain quantitative results from the acquired dataset in the form of 3D strain maps which can be directly correlated to the material properties. Furthermore, we show that the developed framework is capable of strongly reducing motion artifacts even in a dataset containing a single 360° rotation.
May 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29763951/dynamic-4d-ct-angiography-for-guiding-transarterial-chemoembolization-impact-on-the-reduction-of-contrast-material-operator-radiation-exposure-catheter-consumption-and-diagnostic-confidence
#3
Moritz H Albrecht, Thomas J Vogl, Julian L Wichmann, Simon S Martin, Jan-Erik Scholtz, Sebastian Fischer, Renate M Hammerstingl, Marc Harth, Nour-Eldin A Nour-Eldin, Axel Thalhammer, Stephan Zangos, Ralf W Bauer
PURPOSE:  This study was carried out to investigate the impact of abdominal dynamic four-dimensional CT angiography (4D-CTA) for guiding transarterial chemoembolization (TACE) on the amount of contrast material used, operator radiation exposure, catheter consumption, and diagnostic confidence. MATERIALS AND METHODS:  Written consent was waived for this IRB-approved retrospective study. 29 patients (20 men; mean age: 65.7 ± 11.5 years) with malignant liver lesions underwent 4D-CTA, prior to initial TACE...
June 2018: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
https://www.readbyqxmd.com/read/29761989/-super-resolution-reconstruction-for-lung-four-dimensional-computed-tomography-images-using-multi-model-gaussian-process-regression
#4
Shiting Fang, Tao Zhong, Jin Chen, Yu Zhang
Lung four dimensional computed tomography (4D-CT) can lead to accurate radiotherapy. However, for the safety of patients, the scan spacing of 4D-CT cannot be too small so that the inter-slice resolution of lung 4D-CT is low, and thus the coronal and sagittal images need to be interpolated to obtain high-resolution images. This paper presents a super-resolution reconstruction technique based on multi-model Gaussian process regression. We use the high-resolution transversal images and the corresponding low-resolution images as the training sets...
December 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
https://www.readbyqxmd.com/read/29757473/iterative-inversion-of-deformation-vector-fields-with-feedback-control
#5
Abhishek Kumar Dubey, Alexandros-Stavros Iliopoulos, Xiaobai Sun, Fang-Fang Yin, Lei Ren
PURPOSE: Often, the inverse deformation vector field (DVF) is needed together with the corresponding forward DVF in 4D reconstruction and dose calculation, adaptive radiation therapy, and simultaneous deformable registration. This study aims at improving both accuracy and efficiency of iterative algorithms for DVF inversion, and advancing our understanding of divergence and latency conditions. METHOD: We introduce a framework of fixed-point iteration algorithms with active feedback control for DVF inversion...
May 14, 2018: Medical Physics
https://www.readbyqxmd.com/read/29757471/image-based-retrospective-4d-mri-in-external-beam-radiotherapy-a-comparative-study-with-a-digital-phantom
#6
Chiara Paganelli, John Kipritidis, Danny Lee, Guido Baroni, Paul Keall, Marco Riboldi
PURPOSE: Several image-based retrospective sorting methods of 4D Magnetic Resonance Imaging (4D MRI) have been proposed for respiratory motion reconstruction in external beam radiotherapy. However, the optimal strategy for providing accurate and artefact-free 4D MRI, ideally corresponding to an average breathing cycle, is not yet defined. This study presents a proactive comparison of three published image-based sorting methods, to define a groundwork for benchmarking in 4D MRI. METHODS: Three published 4D MRI methods were selected for image retrospective sorting; body area, mutual information and navigator slice...
May 14, 2018: Medical Physics
https://www.readbyqxmd.com/read/29753549/respiratory-motion-resolved-self-gated-4d-mri-using-rotating-cartesian-k-space-rock-initial-clinical-experience-on-an-mri-guided-radiotherapy-system
#7
Fei Han, Ziwu Zhou, Dongsu Du, Yu Gao, Shams Rashid, Minsong Cao, Narek Shaverdian, John V Hegde, Michael Steinberg, Percy Lee, Ann Raldow, Daniel A Low, Ke Sheng, Yingli Yang, Peng Hu
PURPOSE: To optimize and evaluate the respiratory motion-resolved, self-gated 4D-MRI using Rotating Cartesian K-space (ROCK-4D-MRI) method in a 0.35 T MRI-guided radiotherapy (MRgRT) system. METHODS AND MATERIALS: The study included seven patients with abdominal tumors treated on the MRgRT system. ROCK-4D-MRI and 2D-CINE, was performed immediately after one of the treatment fractions. Motion quantification based on 4D-MRI was compared with those based on 2D-CINE...
May 9, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29729075/relationship-between-size-specific-dose-estimates-and-image-quality-in-computed-tomography-depending-on-patient-size
#8
Hiroki Kawashima, Katsuhiro Ichikawa, Shinsuke Hanaoka, Kosuke Matsubara, Tadanori Takata
This study investigates the relationship between contrast-to-noise ratio (CNR) and size-specific dose estimate (SSDE) in computed tomography (CT) depending on patient size. In addition, the relationship to the auto exposure control (AEC) techniques is examined. A tissue-equivalent material having human-liver energy dependence is developed and used to evaluate these relationships. Three exposure dose levels (constant CT dose index, constant SSDE, and with AEC) are tested using four different phantom sizes (diameter: 15, 20, 25 and 30 cm) in two different CT scanners (SOMATOM Definition Flash, Siemens, and LightSpeed VCT, GE)...
May 4, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29700954/influence-of-respiratory-motion-management-technique-on-radiation-pneumonitis-risk-with-robotic-stereotactic-body-radiation-therapy
#9
Christopher H Chapman, Christopher McGuinness, Alexander R Gottschalk, Sue S Yom, Adam A Garsa, Mekhail Anwar, Steve E Braunstein, Atchar Sudhyadhom, Paul Keall, Martina Descovich
PURPOSE/OBJECTIVES: For lung stereotactic body radiation therapy (SBRT), real-time tumor tracking (RTT) allows for less radiation to normal lung compared to the internal target volume (ITV) method of respiratory motion management. To quantify the advantage of RTT, we examined the difference in radiation pneumonitis risk between these two techniques using a normal tissue complication probability (NTCP) model. MATERIALS/METHOD: 20 lung SBRT treatment plans using RTT were replanned with the ITV method using respiratory motion information from a 4D-CT image acquired at the original simulation...
April 26, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29684782/evaluation-of-normal-lung-tissue-complication-probability-in-gated-and-conventional-radiotherapy-using-the-4d-xcat-digital-phantom
#10
Sara Shahzadeh, Somayeh Gholami, Seyed Mahmood Reza Aghamiri, Hojjat Mahani, Mansoure Nabavi, Faraz Kalantari
PURPOSE: The present study was conducted to investigate normal lung tissue complication probability in gated and conventional radiotherapy (RT) as a function of diaphragm motion, lesion size, and its location using 4D-XCAT digital phantom in a simulation study. MATERIALS AND METHODS: Different time series of 3D-CT images were generated using the 4D-XCAT digital phantom. The binary data obtained from this phantom were then converted to the digital imaging and communication in medicine (DICOM) format using an in-house MATLAB-based program to be compatible with our treatment planning system (TPS)...
April 12, 2018: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/29676240/motion-management-in-pet-ct-technological-solutions
#11
Elena De Ponti, Sabrina Morzenti, Cinzia Crivellaro, Federica Elisei, Andrea Crespi, Luca Guerra
BACKGROUND: Motion due to patient's breathing can introduce heavy bias in PET/CT, both in image quality and quantification. AIM: To review technical aspects of the main solutions available to manage movement in PET/CT studies. METHODS: The following tools were described: Respiratory Gated (RG), Motion Free (MF), End Expiration (EE), Banana Artefact Management (BAM) and Data Driven Gating (DDG). RESULTS: The most diffused solutions (RG, MF, EE) are based on LIST mode acquisition of a PET Field of View (4D FOV), centered on the anatomical region of interest; to link PET data not only to time and to spatial position but also to the corresponding breathing phase, the synchronized acquisition of the patient's breathing curve is performed by an external tracking device...
April 19, 2018: Current Radiopharmaceuticals
https://www.readbyqxmd.com/read/29659023/a-dynamic-model-based-approach-to-motion-and-deformation-tracking-of-prosthetic-valves-from-biplane-x-ray-images
#12
Martin G Wagner, Charles R Hatt, David A P Dunkerley, Lindsay E Bodart, Amish N Raval, Michael A Speidel
PURPOSE: Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure in which a prosthetic heart valve is placed and expanded within a defective aortic valve. The device placement is commonly performed using two-dimensional fluoroscopic imaging. Within this work, we propose a novel technique to track the motion and deformation of the prosthetic valve in three dimensions based on biplane fluoroscopic image sequences. METHODS: The tracking approach uses a parameterized point cloud model of the valve stent which can undergo rigid 3D transformation and different modes of expansion...
April 16, 2018: Medical Physics
https://www.readbyqxmd.com/read/29656552/better-performance-of-four-dimension-computed-tomography-as-a-localization-procedure-in-normocalcemic-primary-hyperparathyroidism
#13
Phelipe Cunha-Bezerra, Ricardo Vieira, Fernando Amaral, Henrique Cartaxo, Túlio Lima, Ulisses Montarroyos, Francisco Bandeira
INTRODUCTION: The multi-phase or four-dimensional computed tomography (4D CT) has emerged as a promising technique for preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism (PHPT), but little is known about its accuracy in patients with normocalcemic primary hyperparathyroidism (NPHPT). METHODS: A total of 18 patients diagnosed with PHPT underwent three methods of preoperative localization (4D CT, TC-99-Sestamibi scintigraphy and ultrasonography)...
April 15, 2018: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/29644227/pathologic-confirmation-of-valve-thrombosis-detected-by-four-dimensional-computed-tomography-following-valve-in-valve-transcatheter-aortic-valve-replacement
#14
Ambarish Gopal, Nathalia Ribeiro, John J Squiers, Elizabeth M Holper, Michael Black, Deepika Gopal, Molly Szerlip, Katherine B Harrington, Srinivas Potluri, J Michael DiMaio, David L Brown, Paul A Grayburn, Michael J Mack, William T Brinkman
A major concern regarding transcatheter aortic valve replacement (TAVR) is leaflet thrombosis. Four-dimensional computed tomography (4D-CT) is the preferred imaging modality to evaluate patients with suspected valve thrombosis. To date, the abnormal findings visualized by 4D-CT suggestive of leaflet thrombosis have lacked pathologic confirmation from a surgically explanted valve in a surviving patient. Herein, we provide pathologic confirmation of thrombus formation following surgical explantation of a thrombosed TAVR prosthesis that was initially identified by 4D-CT...
June 30, 2017: Global Cardiology Science & Practice
https://www.readbyqxmd.com/read/29616984/effectiveness-of-different-rescanning-techniques-for-scanned-proton-radiotherapy-in-lung-cancer-patients
#15
Erik Engwall, Lars Glimelius, Elin Hynning
Non-
 small cell lung cancer (NSCLC) is a tumour type thought to be well-suited for
 proton radiotherapy. However, the lung region poses many problems related to organ
 motion and can for actively scanned beams induce severe interplay effects. In this study we investigate four mitigating rescanning techniques: (1) volumetric rescanning, (2) layered rescanning, (3) breath-sampled (BS) layered rescanning, and (4) continuous breath-sampled (CBS) layered rescanning. The breath-sampled methods will spread the layer rescans over a full breathing cycle, resulting in an improved averaging effect at the expense of longer treatment times...
April 4, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29606523/influence-of-deformable-image-registration-on-4d-dose-simulation-for-extracranial-sbrt-a-multi-registration-framework-study
#16
Nik Mogadas, Thilo Sothmann, Tobias Knopp, Tobias Gauer, Cordula Petersen, René Werner
BACKGROUND AND PURPOSE: To evaluate the influence of deformable image registration approaches on correspondence model-based 4D dose simulation in extracranial SBRT by means of open source deformable image registration (DIR) frameworks. MATERIAL AND METHODS: Established DIR algorithms of six different open source DIR frameworks were considered and registration accuracy evaluated using freely available 4D image data. Furthermore, correspondence models (regression-based correlation of external breathing signal measurements and internal structure motion field) were built and model accuracy evaluated...
March 29, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29603002/computer-tomographic-analysis-of-organ-motion-caused-by-respiration-and-intraoperative-pneumoperitoneum-in-a-porcine-model-for-navigated-minimally-invasive-esophagectomy
#17
Felix Nickel, Hannes G Kenngott, Jochen Neuhaus, Nathanael Andrews, Carly Garrow, Johannes Kast, Christof M Sommer, Tobias Gehrig, Carsten N Gutt, Hans-Peter Meinzer, Beat P Müller-Stich
BACKGROUND: Navigation systems have the potential to facilitate intraoperative orientation and recognition of anatomical structures. Intraoperative accuracy of navigation in thoracoabdominal surgery depends on soft tissue deformation. We evaluated esophageal motion caused by respiration and pneumoperitoneum in a porcine model for minimally invasive esophagectomy. METHODS: In ten pigs (20-34 kg) under general anesthesia, gastroscopic hemoclips were applied to the cervical (CE), high (T1), middle (T2), and lower thoracic (T3) level, and to the gastroesophageal junction (GEJ) of the esophagus...
March 30, 2018: Surgical Endoscopy
https://www.readbyqxmd.com/read/29571904/assessment-of-dosimetric-errors-induced-by-deformable-image-registration-methods-in-4d-pencil-beam-scanned-proton-treatment-planning-for-liver-tumours
#18
Cássia O Ribeiro, Antje Knopf, Johannes A Langendijk, Damien C Weber, Antony J Lomax, Ye Zhang
PURPOSE: Respiratory impacts in pencil beam scanned proton therapy (PBS-PT) are accounted by extensive 4D dose calculations, where deformable image registration (DIR) is necessary for estimating deformation vector fields (DVFs). We aim here to evaluate the dosimetric errors induced by different DIR algorithms in their resulting 4D dose calculations by using ground truth(GT)-DVFs from 4DMRI. MATERIALS AND METHODS: Six DIR methods: ANACONDA, Morfeus, B-splines, Demons, CT Deformable, and Total Variation, were respectively applied to nine 4DCT-MRI liver data sets...
March 20, 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29562567/a-fast-4d-cone-beam-ct-reconstruction-method-based-on-the-osc-tv-algorithm
#19
Julia Mascolo-Fortin, Dmitri Matenine, Louis Archambault, Philippe Després
BACKGROUND: Four-dimensional cone beam computed tomography allows for temporally resolved imaging with useful applications in radiotherapy, but raises particular challenges in terms of image quality and computation time. OBJECTIVE: The purpose of this work is to develop a fast and accurate 4D algorithm by adapting a GPU-accelerated ordered subsets convex algorithm (OSC), combined with the total variation minimization regularization technique (TV). METHODS: Different initialization schemes were studied to adapt the OSC-TV algorithm to 4D reconstruction: each respiratory phase was initialized either with a 3D reconstruction or a blank image...
March 15, 2018: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/29547711/left-atrial-appendage-segmentation-and-quantitative-assisted-diagnosis-of-atrial-fibrillation-based-on-fusion-of-temporal-spatial-information
#20
Cheng Jin, Jianjiang Feng, Lei Wang, Heng Yu, Jiang Liu, Jiwen Lu, Jie Zhou
In this paper, we present an approach for left atrial appendage (LAA) multi-phase fast segmentation and quantitative assisted diagnosis of atrial fibrillation (AF) based on 4D-CT data. We take full advantage of the temporal dimension information to segment the living, flailed LAA based on a parametric max-flow method and graph-cut approach to build 3-D model of each phase. To assist the diagnosis of AF, we calculate the volumes of 3-D models, and then generate a "volume-phase" curve to calculate the important dynamic metrics: ejection fraction, filling flux, and emptying flux of the LAA's blood by volume...
March 9, 2018: Computers in Biology and Medicine
keyword
keyword
92855
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"