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4D CT

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https://www.readbyqxmd.com/read/29142240/robust-segmentation-of-the-full-cerebral-vasculature-in-4d-ct-of-suspected-stroke-patients
#1
Midas Meijs, Ajay Patel, Sil C van de Leemput, Mathias Prokop, Ewoud J van Dijk, Frank-Erik de Leeuw, Frederick J A Meijer, Bram van Ginneken, Rashindra Manniesing
A robust method is presented for the segmentation of the full cerebral vasculature in 4-dimensional (4D) computed tomography (CT). The method consists of candidate vessel selection, feature extraction, random forest classification and postprocessing. Image features include among others the weighted temporal variance image and parameters, including entropy, of an intensity histogram in a local region at different scales. These histogram parameters revealed to be a strong feature in the detection of vessels regardless of shape and size...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29136282/principal-component-reconstruction-pcr-for-cine-cbct-with-motion-learning-from-2d-fluoroscopy
#2
Hao Gao, Yawei Zhang, Lei Ren, Fang-Fang Yin
PURPOSE: This work aims to generate cine CT images (i.e., 4D images with high temporal resolution) based on a novel principal component reconstruction (PCR) technique with motion learning from 2D fluoroscopic training images. METHODS: In the proposed PCR method, the matrix factorization is utilized as an explicit low-rank regularization of 4D images that are represented as a product of spatial principal components and temporal motion coefficients. The key hypothesis of PCR is that temporal coefficients from 4D images can be reasonably approximated by temporal coefficients learned from 2D fluoroscopic training projections...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29134472/real-time-wireless-tumor-tracking-during-breast-conserving-surgery
#3
Natasja Janssen, Roeland Eppenga, Marie-Jeanne Vrancken Peeters, Frederieke van Duijnhoven, Hester Oldenburg, Jos van der Hage, Emiel Rutgers, Jan-Jakob Sonke, Koert Kuhlmann, Theo Ruers, Jasper Nijkamp
PURPOSE: To evaluate a novel surgical navigation system for breast conserving surgery (BCS), based on real-time tumor tracking using the Calypso[Formula: see text] 4D Localization System (Varian Medical Systems Inc., USA). Navigation-guided breast conserving surgery (Nav-BCS) was compared to conventional iodine seed-guided BCS ([Formula: see text]I-BCS). METHODS: Two breast phantom types were produced, containing spherical and complex tumors in which wireless transponders (Nav-BCS) or a iodine seed ([Formula: see text]I-BCS) were implanted...
November 13, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/29127775/four-dimensional-computed-tomography-evaluation-of-condylar-movement-in-a-patient-with-temporomandibular-joint-osteoarthritis
#4
Masaya Akashi, Takumi Hasegawa, Satoru Takahashi, Takahide Komori
Temporomandibular joint (TMJ) osteoarthritis (OA) is a disease of the bone, cartilage, and supporting tissues of the joint. Patients with advanced TMJ-OA often have symptoms such as pain, swelling, and joint dysfunction, and they sometimes require surgical intervention when conservative treatment is not effective. The etiology of TMJ-OA remains elusive. The usefulness of 4-dimensional (4D) computed tomography (CT) in motion analysis of various joints has recently been reported. This article introduces a novel imaging technique of 4D CT that aims to identify kinematic features that may be associated with the etiology of TMJ-OA...
October 16, 2017: Journal of Oral and Maxillofacial Surgery
https://www.readbyqxmd.com/read/29122361/ventilation-measured-on-clinical-4d-cbct-increased-ventilation-accuracy-through-improved-image-quality
#5
Kasper R Jensen, Carsten Brink, Olfred Hansen, Uffe Bernchou
BACKGROUND AND PURPOSE: Ventilation measured on 4D cone-beam computed tomography (CBCT) using deformable image registration (DIR) may predict specific radiation sensitivity, but the measurement is affected by the current image quality. With 4D computed tomography (CT) measured ventilation acting as a gold standard the current study investigates if image improvements increase the accuracy of 4D-CBCT measured ventilation. MATERIAL AND METHODS: The study consists of 4D-CBCT and 4D-CT scans of 20 non-small-cell lung cancer patients...
November 6, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29072320/technical-note-correction-for-the-effect-of-breathing-variations-in-ct-pulmonary-ventilation-imaging
#6
Tokihiro Yamamoto, Sven Kabus
PURPOSE: The accuracy and precision of computed tomography (CT) pulmonary ventilation imaging with conventional CT scanners are limited by breathing variations. We propose a method to correct for the effect of breathing variations in CT ventilation imaging based on external respiratory signals acquired throughout a scan. METHODS: The proposed method is based on: (1) calculating voxel-by-voxel abdominal surface motion ranges using four-dimensional (4D) CT image datasets spatiotemporally correlated with external respiratory monitor data, and (2) applying the correction factor, which is defined as the ratio of the overall mean of the abdominal surface motion range in the lungs to that of each voxel, to the CT ventilation value...
October 26, 2017: Medical Physics
https://www.readbyqxmd.com/read/29060628/volumetric-analysis-of-respiratory-gated-whole-lung-and-liver-ct-data-with-motion-constrained-graph-cuts-segmentation
#7
Jung Won Cha, M Mehdi Farhangi, Neal Dunlap, Amir Amini
The conventional graph cuts technique has been widely used for image segmentation due to its ability to find the global minimum and its ease of implementation. However, it is an intensity-based technique and as a result is limited to segmentation applications where there is significant contrast between the object and the background. We modified the conventional graph cuts method by adding shape prior and motion information. Active shape models (ASM) with signed distance functions were used to capture the shape prior information, preventing unwanted surrounding tissue from becoming part of the segmented object...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/29059054/correspondence-model-based-4d-vmat-dose-simulation-for-analysis-of-local-metastasis-recurrence-after-extracranial-sbrt
#8
Thilo Sothmann, Tobias Gauer, Matthias Wilms, René Werner
The purpose of this study is to introduce a novel approach to incorporate patient-specific breathing variability information into 4D dose simulation of volumetric arc therapy (VMAT)-based stereotactic body radiotherapy (SBRT) of extracranial metastases. Feasibility of the approach is illustrated by application to treatment planning and motion data of lung and liver metastasis patients. The novel 4D dose simulation approach makes use of a regression-based correspondence model that allows representing patient motion variability by breathing signal-steered interpolation and extrapolation of deformable image registration motion fields...
October 23, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29045239/contour-propagation-for-lung-tumor-delineation-in-4d-ct-using-tensor-product-surface-of-uniform-and-non-uniform-closed-cubic-b-splines
#9
Renchao Jin, Yongchuan Liu, Mi Chen, Sheng Zhang, Enmin Song
A robust contour propagation method is proposed to help physicians delineate lung tumors on all phase images of four-dimensional computer tomography (4D-CT) by only manually delineating the contours on a reference phase. The proposed method models the trajectory surface swept by a contour in a respiratory cycle as a tensor-product surface of two closed cubic B-spline curves: a non-uniform B-spline curve which models the contour and a uniform B-spline curve which models the trajectory of a point on the contour...
October 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29041117/movit-a-tomographic-reconstruction-framework-for-4d-ct
#10
Vincent Van Nieuwenhove, Jan De Beenhouwer, Jelle Vlassenbroeck, Mark Brennan, Jan Sijbers
4D computed tomography (4D-CT) aims to visualise the temporal dynamics of a 3D sample with a sufficiently high temporal and spatial resolution. Successive time frames are typically obtained by sequential scanning, followed by independent reconstruction of each 3D dataset. Such an approach requires a large number of projections for each scan to obtain images with sufficient quality (in terms of artefacts and SNR). Hence, there is a clear trade-off between the rotation speed of the gantry (i.e. time resolution) and the quality of the reconstructed images...
August 7, 2017: Optics Express
https://www.readbyqxmd.com/read/29037025/gross-tumor-volume-dependency-on-phase-sorting-methods-of-four-dimensional-computed-tomography-images-for-lung-cancer
#11
Soo Yong Lee, Sangwook Lim, Sun Young Ma, Jesang Yu
PURPOSE: To see the gross tumor volume (GTV) dependency according to the phase selection and reconstruction methods, we measured and analyzed the changes of tumor volume and motion at each phase in 20 cases with lung cancer patients who underwent image-guided radiotherapy. MATERIALS AND METHODS: We retrospectively analyzed four-dimensional computed tomography (4D-CT) images in 20 cases of 19 patients who underwent image-guided radiotherapy. The 4D-CT images were reconstructed by the maximum intensity projection (MIP) and the minimum intensity projection (Min-IP) method after sorting phase as 40%-60%, 30%-70%, and 0%-90%...
September 2017: Radiation Oncology Journal
https://www.readbyqxmd.com/read/29036875/three-novel-accurate-pixel-driven-projection-methods-for-2d-ct-and-3d-epr-imaging
#12
Zhiwei Qiao, Gage Redler, Zhiguo Gui, Yuhua Qian, Boris Epel, Howard Halpern
OBJECTIVES: This work aims to explore more accurate pixel-driven projection methods for iterative image reconstructions in order to reduce high-frequency artifacts in the generated projection image. METHODS: Three new pixel-driven projection methods namely, small-pixel-large-detector (SPLD), linear interpolation based (LIB) and distance anterpolation based (DAB), were proposed and applied to reconstruct images. The performance of these methods was evaluated in both two-dimensional (2D) computed tomography (CT) images via the modified FORBILD phantom and three-dimensional (3D) electron paramagnetic resonance (EPR) images via the 6-spheres phantom...
October 10, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/29023143/changes-of-emphysema-parameters-over-the-respiratory-cycle-during-free-breathing-preliminary-results-using-respiratory-gated-4d-ct
#13
Julia Ley-Zaporozhan, Sebastian Ley, Jürgen Mews, Oliver Weinheimer, Sonja Kandel, Patrik Rogalla
The purpose of this research was to evaluate respiratory gated CT of the lung in patients with COPD for analysis of parenchymal characteristics who were potential candidates for volume reduction surgery. Eleven patients with clinically known emphysematous disease underwent a respiratory gated, free-breathing 64-multislice-CT (Aquilion 64, Toshiba). Retrospective image reconstruction was performed similar to cardiac CT at every 10% of the respiratory loop, resulting in 10 complete volumetric datasets at 10 equidistant time points...
October 12, 2017: COPD
https://www.readbyqxmd.com/read/28992962/the-long-and-short-term-variability-of-breathing-induced-tumor-motion-in-lung-and-liver-over-the-course-of-a-radiotherapy-treatment
#14
Jennifer Dhont, Jef Vandemeulebroucke, Manuela Burghelea, Kenneth Poels, Tom Depuydt, Robbe Van Den Begin, Cyril Jaudet, Christine Collen, Benedikt Engels, Truus Reynders, Marlies Boussaer, Thierry Gevaert, Mark De Ridder, Dirk Verellen
PURPOSE: To evaluate the short and long-term variability of breathing induced tumor motion. MATERIALS AND METHODS: 3D tumor motion of 19 lung and 18 liver lesions captured over the course of an SBRT treatment were evaluated and compared to the motion on 4D-CT. An implanted fiducial could be used for unambiguous motion information. Fast orthogonal fluoroscopy (FF) sequences, included in the treatment workflow, were used to evaluate motion during treatment. Several motion parameters were compared between different FF sequences from the same fraction to evaluate the intrafraction variability...
October 6, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28992047/preliminary-comparison-of-the-registration-effect-of-4d-cbct-and-3d-cbct-in-image-guided-radiotherapy-of-stage-ia-non-small-cell-lung-cancer
#15
Zhibo Tan, Chuanyao Liu, Ying Zhou, Weixi Shen
In this study, we compared the registration effectiveness of 4D cone-beam computed tomography (CBCT) and 3D-CBCT for image-guided radiotherapy in 20 Stage IA non-small-cell lung cancer (NSCLC) patients. Patients underwent 4D-CBCT and 3D-CBCT immediately before radiotherapy, and the X-ray Volume Imaging software system was used for image registration. We performed automatic bone registration and soft tissue registration between 4D-CBCT or 3D-CBCT and 4D-CT images; the regions of interest (ROIs) were the vertebral body on the layer corresponding to the tumor and the internal target volume region...
July 15, 2017: Journal of Radiation Research
https://www.readbyqxmd.com/read/28987702/the-diagnostic-accuracy-of-neck-ultrasound-4d-computed-tomographyand-sestamibi-imaging-in-parathyroid-carcinoma
#16
Ioannis Christakis, Thinh Vu, Hubert H Chuang, Bryan Fellman, Angelica M Silva Figueroa, Michelle D Williams, Naifa L Busaidy, Nancy D Perrier
INTRODUCTION: Our aim was to investigate the accuracy of available imaging modalities for parathyroid carcinoma (PC) in our institution and to identify which imaging modality, or combination thereof, is optimal in preoperative determination of precise tumor location. METHODS: All operated PC patients in our institution between 2000 and 2015 that had at least one of the following in-house preoperative scans: neck ultrasonography (US), neck 4D-Computed Tomography (4DCT) and 99mTc Sestamibi SPECT/CT (MIBI)...
October 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28980395/improved-vessel-tissue-contrast-and-image-quality-in-3d-radial-sampling-based-4d-mri
#17
Zixin Deng, Wensha Yang, Jianing Pang, Xiaoming Bi, Richard Tuli, Debiao Li, Zhaoyang Fan
PURPOSE: In radiation treatment planning for thoracic and abdominal tumors, 4D-MRI has shown promise in respiratory motion characterization with improved soft-tissue contrast compared to clinical standard, 4D computed tomography (4D-CT). This study aimed to further improve vessel-tissue contrast and overall image quality in 3D radial sampling-based 4D-MRI using a slab-selective (SS) excitation approach. METHODS: The technique was implemented in a 3D radial sampling with self-gating-based k-space sorting sequence...
October 4, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28978306/respiratory-gated-4d-contrast-enhanced-fdg-pet-ct-for-radiotherapy-planning-of-lower-oesophageal-carcinoma-feasibility-and-impact-on-planning-target-volume
#18
Andrew Scarsbrook, Gillian Ward, Patrick Murray, Rebecca Goody, Karen Marshall, Garry McDermott, Robin Prestwich, Ganesh Radhakrishna
BACKGROUND: To assess the feasibility and potential impact on target delineation of respiratory-gated (4D) contrast-enhanced (18)Fluorine fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT), in the treatment planning position, for a prospective cohort of patients with lower third oesophageal cancer. METHODS: Fifteen patients were recruited into the study. Imaging included 4D PET-CT, 3D PET-CT, endoscopic ultrasound and planning 4D CT...
October 4, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28970037/a-novel-method-for-evaluating-regional-rv-function-in-the-adult-congenital-heart-with-low-dose-ct-and-squeez-processing
#19
Francisco J Contijoch, Daniel W Groves, Zhennong Chen, Marcus Y Chen, Elliot R McVeigh
BACKGROUND: Measuring local RV function in adult congenital heart disease (ACHD) with echocardiography or MRI is challenging because of the complex geometry and existing pacing devices. Visual assessment of ventricular function via low-dose cardiac CT has been recently performed. This pilot study assessed whether low-dose 4D cine CT combined with automatic measurement of regional shortening could quantify right-ventricular function in ACHD patients. METHODS: Seven patients with Tetralogy of Fallot either contraindicated for MRI or assessed for coronary artery disease and seven non-congenital patients were imaged with ECG-gated cardiac CT utilizing a 320-detector row scanner...
December 15, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28967574/vectors-through-a-cross-sectional-image-vci-a-visualization-method-for-four-dimensional-motion-analysis-for-cardiac-computed-tomography
#20
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...
September 23, 2017: Journal of Cardiovascular Computed Tomography
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