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4D CT

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https://www.readbyqxmd.com/read/27917312/a-4d-ct-digital-phantom-of-an-individual-human-brain-for-perfusion-analysis
#1
Rashindra Manniesing, Christoph Brune, Bram van Ginneken, Mathias Prokop
Brain perfusion is of key importance to assess brain function. Modern CT scanners can acquire perfusion maps of the cerebral parenchyma in vivo at submillimeter resolution. These perfusion maps give insights into the hemodynamics of the cerebral parenchyma and are critical for example for treatment decisions in acute stroke. However, the relations between acquisition parameters, tissue attenuation curves, and perfusion values are still poorly understood and cannot be unraveled by studies involving humans because of ethical concerns...
2016: PeerJ
https://www.readbyqxmd.com/read/27894001/multiresolution-extended-free-form-deformations-xffd-for-non-rigid-registration-with-discontinuous-transforms
#2
Rui Hua, Jose M Pozo, Zeike A Taylor, Alejandro F Frangi
Image registration is an essential technique to obtain point correspondences between anatomical structures from different images. Conventional non-rigid registration methods assume a continuous and smooth deformation field throughout the image. However, the deformation field at the interface of different organs is not necessarily continuous, since the organs may slide over or separate from each other. Therefore, imposing continuity and smoothness ubiquitously would lead to artifacts and increased errors near the discontinuity interface...
November 9, 2016: Medical Image Analysis
https://www.readbyqxmd.com/read/27891248/synchrotron-4-dimensional-imaging-of-two-phase-flow-through-porous-media
#3
F H Kim, D Penumadu, P Patel, X Xiao, E J Garboczi, S P Moylan, M A Donmez
Near real-time visualization of complex two-phase flow in a porous medium was demonstrated with dynamic 4-dimensional (4D) (3D + time) imaging at the 2-BM beam line of the Advanced Photon Source (APS) at Argonne National Laboratory. Advancing fluid fronts through tortuous flow paths and their interactions with sand grains were clearly captured, and formations of air bubbles and capillary bridges were visualized. The intense X-ray photon flux of the synchrotron facility made 4D imaging possible, capturing the dynamic evolution of both solid and fluid phases...
2016: MRS Adv
https://www.readbyqxmd.com/read/27887983/method-of-evaluating-respiratory-induced-organ-motion-by-vector-volume-histogram
#4
Hideharu Miura, Shuichi Ozawa, Hideo Kawabata, Yoshiko Doi, Masahiro Kenjou, Kengo Furukawa, Minoru Nakao, Yasushi Nagata
PURPOSE: Published organ motion data have been collected from measurements of a limited number of points within the organ, the centroid, or the edge of the organ. These are derived from the spatial characteristics of respiratory induced motion; however, this approach does not consider non-rigid organ deformation. We propose a novel quantitative method for evaluating respiratory induced organ motion using Deformable Image Registration (DIR). METHOD: Two phases from a 4-dimensional computed tomography (4D CT) dataset at maximum inspiration and expiration were each taken from five patients...
November 22, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27879289/remote-multifocal-bleeding-points-producing-a-sylvian-subpial-hematoma-during-endovascular-coiling-of-an-acutely-ruptured-cerebral-aneurysm
#5
Christopher Alan Hilditch, Hemant Sonwalkar, Siddhartha Wuppalapati
Subpial hematoma is a rare type of intracranial hemorrhage with a poor prognosis. A new mechanism to explain subpial Sylvian hematoma formation in acute post-aneurysmal subarachnoid hemorrhage (SAH) was observed during coiling of a posterior communicating artery aneurysm. Multiple small bleeding points from pial branches of the left middle cerebral artery, which were remote from the ruptured aneurysm, were observed on conventional angiography. This bleeding led to the formation of a large expanding subpial Sylvian hematoma...
November 22, 2016: Journal of Neurointerventional Surgery
https://www.readbyqxmd.com/read/27862910/dynamic-updating-atlas-for-heart-segmentation-with-a-nonlinear-field-based-model
#6
Ken Cai, Rongqian Yang, Hongwei Yue, Lihua Li, Shanxing Ou, Feng Liu
BACKGROUND: Segmentation of cardiac computed tomography (CT) images is an effective method for assessing the dynamic function of the heart and lungs. In the atlas-based heart segmentation approach, the quality of segmentation usually relies upon atlas images, and the selection of those reference images is a key step. The optimal goal in this selection process is to have the reference images as close to the target image as possible. METHODS: This study proposes an atlas dynamic update algorithm using a scheme of nonlinear deformation field...
November 9, 2016: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/27856529/remote-multifocal-bleeding-points-producing-a-sylvian-subpial-hematoma-during-endovascular-coiling-of-an-acutely-ruptured-cerebral-aneurysm
#7
Christopher Alan Hilditch, Hemant Sonwalkar, Siddhartha Wuppalapati
Subpial hematoma is a rare type of intracranial hemorrhage with a poor prognosis. A new mechanism to explain subpial Sylvian hematoma formation in acute post-aneurysmal subarachnoid hemorrhage (SAH) was observed during coiling of a posterior communicating artery aneurysm. Multiple small bleeding points from pial branches of the left middle cerebral artery, which were remote from the ruptured aneurysm, were observed on conventional angiography. This bleeding led to the formation of a large expanding subpial Sylvian hematoma...
November 17, 2016: BMJ Case Reports
https://www.readbyqxmd.com/read/27846916/intrafractional-dose-variation-and-beam-configuration-in-carbon-ion-radiotherapy-for-esophageal-cancer
#8
M F Haefner, F Sterzing, D Krug, S A Koerber, O Jaekel, J Debus, M M Haertig
BACKGROUND: In carbon ion radiotherapy (CIR) for esophageal cancer, organ and target motion is a major challenge for treatment planning due to potential range deviations. This study intends to analyze the impact of intrafractional variations on dosimetric parameters and to identify favourable settings for robust treatment plans. METHODS: We contoured esophageal boost volumes in different organ localizations for four patients and calculated CIR-plans with 13 different beam geometries on a free-breathing CT...
November 15, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27832419/temporal-averaging-for-analysis-of-four-dimensional-whole-heart-computed-tomography-perfusion-of-the-myocardium-proof-of-concept-study
#9
S Feger, A Shaban, S Lukas, C Kendziorra, M Rief, E Zimmermann, M Dewey
To assess the feasibility of four-dimensional (4D) whole-heart computed tomography perfusion (CTP) of the myocardium and the added value of temporal averaging of consecutive 3D datasets from different heartbeats for analysis. We included 30 patients with suspected or known coronary artery disease (CAD) who underwent 320-row coronary CT angiography (CTA) and myocardial CTP. Out of these, 15 patients underwent magnetic resonance myocardial perfusion imaging (MR MPI). All CTP examinations were initiated after 3 min of intravenous infusion of adenosine (140 µg/kg/min) and were performed dynamically covering the entire heart every heart beat over a period of 20 ± 3 heart beats...
November 10, 2016: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/27815727/initial-experiments-with-gel-water-towards-mri-linac-dosimetry-and-imaging
#10
Sarah J Alnaghy, Maegan Gargett, Gary Liney, Marco Petasecca, Jarrad Begg, Anthony Espinoza, Matthew K Newall, Mitchell Duncan, Lois Holloway, Michael L F Lerch, Mircea Lazea, Anatoly B Rosenfeld, Peter Metcalfe
Tracking the position of a moving radiation detector in time and space during data acquisition can replicate 4D image-guided radiotherapy (4DIGRT). Magnetic resonance imaging (MRI)-linacs need MRI-visible detectors to achieve this, however, imaging solid phantoms is an issue. Hence, gel-water, a material that provides signal for MRI-visibility, and which will in future work, replace solid water for an MRI-linac 4DIGRT quality assurance tool, is discussed. MR and CT images of gel-water were acquired for visualisation and electron density verification...
November 4, 2016: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/27811397/is-there-an-ideal-set-of-prospective-scan-acquisition-phases-for-fast-helical-based-4d-ct
#11
D H Thomas, D Ruan, P Williams, J Lamb, B M White, T Dou, D O'Connell, P Lee, D A Low
The article aims to determine if a prospective acquisition algorithm can be used to find the ideal set of free-breathing phases for fast-helical model-based 4D-CT. A retrospective five-patient dataset that consisted of 25 repeated free breathing CT scans per patient was used. The sum of the square root amplitude difference between all the breathing phases was defined as an objective function to determine the optimality of sets of breathing phases. The objective function was intended to determine if a specific set of breathing phases would yield a motion model that could accurately predict the motion in all 25 CT scans...
December 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27809555/quantitative-analysis-of-subtalar-joint-motion-with-4d-ct-proof-of-concept-with-cadaveric-and-healthy-subject-evaluation
#12
Pedro Augusto Gondim Teixeira, Anne-Sophie Formery, Adrien Jacquot, Guillaume Lux, Isabelle Loiret, Manuela Perez, Alain Blum
OBJECTIVE: The purpose of this study was to show the application of quantitative 4D CT for subtalar joint evaluation in healthy volunteers and cadavers. MATERIALS AND METHODS: Fifteen healthy volunteers with no history of subtalar joint trauma and three cadavers were prospectively evaluated with dynamic CT. The subtalar joint was evaluated during a pronosupination cycle. All acquisitions (cadavers and healthy volunteers) were performed using intermittent sequential mode with a 320-MDCT scanner...
November 3, 2016: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/27806580/robotic-intrafractional-us-guidance-for-liver-sabr-system-design-beam-avoidance-and-clinical-imaging
#13
Jeffrey Schlosser, Ren Hui Gong, Ralf Bruder, Achim Schweikard, Sungjune Jang, John Henrie, Aya Kamaya, Albert Koong, Daniel T Chang, Dimitre Hristov
PURPOSE: To present a system for robotic 4D ultrasound (US) imaging concurrent with radiotherapy beam delivery and estimate the proportion of liver stereotactic ablative body radiotherapy (SABR) cases in which robotic US image guidance can be deployed without interfering with clinically used VMAT beam configurations. METHODS: The image guidance hardware comprises a 4D US machine, an optical tracking system for measuring US probe pose, and a custom-designed robot for acquiring hands-free US volumes...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27803968/preoperative-3d-and-4d-ct-imaging-using-640-multislice-ct-640-msct-in-diagnosis-of-female-urethral-diverticulum
#14
Yong-Xian Zhao, Jia-Ping Wang, Jiong-Ming Li, Tao Chen, Cong-Wen Mao, Jian-He Liu, Yun-Shan Su, Ke-Wei Fang
OBJECTIVE: To determine the sensitivity and specificity of 640-Multislice CT (640-MSCT) in diagnosing the female UD. MATERIALS AND METHODS: We investigated 16 patients with symptomatic UDs preoperatively in our hospital from August 2010 to March 2016. The patients' average age was 38.8 years. All patients were performed 640-MSCT of pelvis; then, 3D and 4D images were reconstructed preoperatively. RESULTS: In 3D and 4D-CT images, out of 16 patients, thirteen patients had one ostium, two had 2 ostia and one had 3 ostia...
November 1, 2016: World Journal of Urology
https://www.readbyqxmd.com/read/27782722/simultaneous-4d-cbct-reconstruction-with-sliding-motion-constraint
#15
Jun Dang, Fang-Fang Yin, Tao You, Chunhua Dai, Deyu Chen, Jing Wang
PURPOSE: Current approaches using deformable vector field (DVF) for motion-compensated 4D-cone beam CT (CBCT) reconstruction typically utilize an isotropically smoothed DVF between different respiration phases. Such isotropically smoothed DVF does not work well if sliding motion exists between neighboring organs. This study investigated an anisotropic motion modeling scheme by extracting organ boundary local motions (e.g., sliding) and incorporated them into 4D-CBCT reconstruction to optimize the motion modeling and reconstruction methods...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27782714/lung-surface-deformation-prediction-from-spirometry-measurement-and-chest-wall-surface-motion
#16
Joubin Nasehi Tehrani, Alistair McEwan, Jing Wang
PURPOSE: The authors have developed and evaluated a method to predict lung surface motion based on spirometry measurements, and chest and abdomen motion at selected locations. METHODS: A patient-specific 3D triangular surface mesh of the lung region was obtained at the end expiratory phase by the threshold-based segmentation method. Lung flow volume changes were recorded with a spirometer for each patient. A total of 192 selected points at a regular spacing of 2 × 2 cm matrix points were used to detect chest wall motion over a total area of 32 × 24 cm covering the chest and abdomen surfaces...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27782710/individually-optimized-contrast-enhanced-4d-ct-for-radiotherapy-simulation-in-pancreatic-ductal-adenocarcinoma
#17
Wookjin Choi, Ming Xue, Barton F Lane, Min Kyu Kang, Kruti Patel, William F Regine, Paul Klahr, Jiahui Wang, Shifeng Chen, Warren D'Souza, Wei Lu
PURPOSE: To develop an individually optimized contrast-enhanced (CE) 4D-computed tomography (CT) for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA). METHODS: Ten PDA patients were enrolled. Each underwent three CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT using test injection. Three physicians contoured the tumor and pancreatic tissues. Image quality scores, tumor volume, motion, tumor-to-pancreas contrast, and contrast-to-noise ratio (CNR) were compared in the three CTs...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27777822/the-role-of-dynamic-4d-ct-in-the-detection-of-scapholunate-ligament-injury
#18
Sanjeev Kakar, Ryan E Breighner, Shuai Leng, Cynthia H McCollough, Steven L Moran, Richard A Berger, Kristin D Zhao
Background Scapholunate (SL) interosseus ligament injuries detected at an early stage could allow the surgeon to prevent progression through the spectrum of injury that leads to instability, and eventually osteoarthritis. We contend that early instability following injury can be detected by visualizing the relative motions and distances between the involved carpal bones (scaphoid and lunate) during wrist movement in vivo. The purpose of this study is to demonstrate the utility of dynamic CT (i.e., 4DCT) in diagnosing SL interosseus ligament injuries in two patients with clinical suspicion of SL interosseus ligament injury during flexion-extension (FE), radial-ulnar (RU) deviation, and dart thrower's (DT) motions...
November 2016: Journal of Wrist Surgery
https://www.readbyqxmd.com/read/27765913/an-in-vitro-3d-bone-metastasis-model-by-using-a-human-bone-tissue-culture-and-human-sex-related-cancer-cells
#19
Francesca Salamanna, Veronica Borsari, Silvia Brogini, Gianluca Giavaresi, Annapaola Parrilli, Simona Cepollaro, Matteo Cadossi, Lucia Martini, Antonio Mazzotti, Milena Fini
One of the main limitations, when studying cancer-bone metastasis, is the complex nature of the native bone environment and the lack of reliable, simple, inexpensive models that closely mimic the biological processes occurring in patients and allowing the correct translation of results. To enhance the understanding of the mechanisms underlying human bone metastases and in order to find new therapies, we developed an in vitro three-dimensional (3D) cancer-bone metastasis model by culturing human breast or prostate cancer cells with human bone tissue isolated from female and male patients, respectively...
October 19, 2016: Oncotarget
https://www.readbyqxmd.com/read/27762065/32-years-of-experience-with-co2-laser-assisted-treatment-for-zenker-s-diverticulum-an-update-of-227-patients-treated-in-kiel
#20
M Hoffmann, A Fazel, K-G Mews, P Ambrosch
OBJECTIVES: To underline the value of the microendoscopic CO2 -LASER-assisted treatment (MEDCO2 ) for Zenker's diverticulum by investigating a large patient cohort treated in a single medical centre. DESIGN: Retrospective cohort study of consecutive patients. SETTING: Department of Otorhinolaryngology, Head and Neck Surgery, Christian-Albrechts-University Kiel, Germany. PARTICIPANTS: A total of 227 patients with Zenker's diverticulum were treated by MEDCO2 , and the results were compared with those reported in the literature for the open transcervical approach (OTA) and the endoscopic staple-assisted oesophagodiverticulostomy (ESED)...
October 19, 2016: Clinical Otolaryngology
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