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4D Flow

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https://www.readbyqxmd.com/read/28226737/4d-lung-tumor-segmentation-via-shape-prior-and-motion-cues
#1
Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini, Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini, Jung Won Cha, Amir Amini, Neal Dunlap, Mohammad M Farhangi
Lung tumor segmentation is important for therapy in the radiation treatment of patients with thoracic malignancies. In this paper, we describe a 4D image segmentation method based on graph-cuts optimization, shape prior and optical flow. Due to small size, the location, and low contrast between the tumor and the surrounding tissue, tumor segmentation in 3D+t is challenging. We performed 4D lung tumor segmentation in 5 patients, and in each case compared the results with the expert-delineated lung nodules. In each case, 4D image segmentation took approximately ten minutes on a PC with AMD Phenom II and 32GB of memory for segmenting tumor in five phases of lung CT data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225577/image-based-background-phase-error-correction-in-4d-flow-mri-revisited
#2
Julia Busch, Daniel Giese, Sebastian Kozerke
PURPOSE: To correct background phase errors in phase-contrast magnetic resonance imaging (MRI), image-based correction by referencing through stationary tissue is widely used. The aim of the present study was a detailed assessment of background phase errors in 4D Flow MRI and limitations of image-based correction. MATERIALS AND METHODS: In a phantom study, 4D Flow MRI data were acquired for typical settings on two clinical 3T MR systems. Background errors were analyzed with respect to their spatial order and minimum requirements regarding the signal-to-noise ratio (SNR) and the amount of stationary tissue for image-based correction were assessed...
February 22, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28185475/4d-flow-magnetic-resonance-imaging-role-in-pediatric-congenital-heart-disease
#3
Claire M Lawley, Kathryn M Broadhouse, Fraser M Callaghan, David S Winlaw, Gemma A Figtree, Stuart M Grieve
Imaging-based evaluation of cardiac structure and function remains paramount in the diagnosis and monitoring of congenital heart disease in childhood. Accurate measurements of intra- and extracardiac hemodynamics are required to inform decision making, allowing planned timing of interventions prior to deterioration of cardiac function. Four-dimensional flow magnetic resonance imaging is a nonionizing noninvasive technology that allows accurate and reproducible delineation of blood flow at any anatomical location within the imaging volume of interest, and also permits derivation of physiological parameters such as kinetic energy and wall shear stress...
January 1, 2017: Asian Cardiovascular & Thoracic Annals
https://www.readbyqxmd.com/read/28184976/decreased-diastolic-ventricular-kinetic-energy-in-young-patients-with-fontan-circulation-demonstrated-by-four-dimensional-cardiac-magnetic-resonance-imaging
#4
Pia Sjöberg, Einar Heiberg, Pär Wingren, Jens Ramgren Johansson, Torsten Malm, Håkan Arheden, Petru Liuba, Marcus Carlsson
Four-dimensional (4D) flow magnetic resonance imaging (MRI) enables quantification of kinetic energy (KE) in intraventricular blood flow. This provides a novel way to understand the cardiovascular physiology of the Fontan circulation. In this study, we aimed to quantify the KE in functional single ventricles. 4D flow MRI was acquired in eleven patients with Fontan circulation (median age 12 years, range 3-29) and eight healthy volunteers (median age 26 years, range 23-36). Follow-up MRI after surgical or percutaneous intervention was performed in 3 patients...
February 10, 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/28174322/4d-microvascular-analysis-reveals-that-regenerative-angiogenesis-in-ischemic-muscle-produces-a-flawed-microcirculation
#5
John-Michael Arpino, Zengxuan Nong, Fuyan Li, Hao Yin, Nour W Ghonaim, Stephanie Milkovich, Brittany Balint, Caroline O'Neil, Graham M Fraser, Daniel Goldman, Christopher G Ellis, J G Pickering
RATIONALE: Angiogenesis occurs following ischemic injury to skeletal muscle and enhancing this response has been a therapeutic goal. However, to appropriately deliver oxygen, a precisely organized and exquisitely responsive microcirculation must form. Whether these network attributes exist in a regenerated microcirculation is unknown and methodologies for answering this have been lacking. OBJECTIVE: To develop 4D methodologies for elucidating microarchitecture and function of the reconstructed microcirculation in skeletal muscle...
February 7, 2017: Circulation Research
https://www.readbyqxmd.com/read/28152259/four-dimensional-phase-contrast-vastly-undersampled-isotropic-projection-reconstruction-4d-pc-vipr-mr-evaluation-of-the-renal-arteries-in-transplant-recipients-preliminary-results
#6
Daisuke Motoyama, Yasuo Ishii, Yasuo Takehara, Masataka Sugiyama, Wang Yang, Hatsuko Nasu, Takasuke Ushio, Yuko Hirose, Naoki Ohishi, Tetsuya Wakayama, Hiroyuki Kabasawa, Kevin Johnson, Oliver Wieben, Harumi Sakahara, Seiichiro Ozono
PURPOSE: To assess the performance of four-dimensional phase-contrast vastly undersampled isotropic projection reconstruction (4D PC-VIPR) at 3.0T in depicting intrarenal arteries compared with computed tomography angiography (CTA), and its correlation with arterial flowmetry in comparison with Doppler ultrasonography (DUS). MATERIALS AND METHODS: In our prospective single-arm study, subjects were 25 patients who underwent renal transplant-related surgery at our hospital between July 2011 and June 2015...
February 2, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28152256/accelerated-dual-venc-4d-flow-mri-for-neurovascular-applications
#7
Susanne Schnell, Sameer A Ansari, Can Wu, Julio Garcia, Ian G Murphy, Ozair A Rahman, Amir A Rahsepar, Maria Aristova, Jeremy D Collins, James C Carr, Michael Markl
PURPOSE: To improve velocity-to-noise ratio (VNR) and dynamic velocity range of 4D flow magnetic resonance imaging (MRI) by using dual-velocity encoding (dual-venc) with k-t generalized autocalibrating partially parallel acquisition (GRAPPA) acceleration. MATERIALS AND METHODS: A dual-venc 4D flow MRI sequence with k-t GRAPPA acceleration was developed using a shared reference scan followed by three-directional low- and high-venc scans (repetition time / echo time / flip angle = 6...
February 2, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28148318/utility-of-4d-flow-mapping-in-eisenmenger-syndrome-with-pulmonary-atresia
#8
Soha Romeih, Heba Aguib, Magdi Yacoub
Management of patients with Eisenmenger syndrome with pulmonary atresia is challenging because of the complexity of the structure-function relationship of the components of the syndrome. Multi-modality imaging including cardiac magnetic resonance (CMR) 4D Flow offers unprecedented opportunities to unravel, at least in part, some of these components, and thus help in the management of these patients. In this study, we describe the use of these integrated methods with particular reference to CMR 4D Flow in a patient with Eisenmenger syndrome and pulmonary atresia and outline both the utility and the limitations...
December 2016: Cardiology in the Young
https://www.readbyqxmd.com/read/28144400/cutting-edge-clinical-applications-in-cardiovascular-magnetic-resonance
#9
EDITORIAL
Carlo N De Cecco, Giuseppe Muscogiuri, Akos Varga-Szemes, U Joseph Schoepf
Today, the use of cardiovascular magnetic resonance (CMR) is widespread in clinical practice. The increased need to evaluate of subtle myocardial changes, coronary artery anatomy, and hemodynamic assessment has prompted the development of novel CMR techniques including T1 and T2 mapping, non-contrast angiography and four dimensional (4D) flow. T1 mapping is suitable for diagnosing pathologies affecting extracellular volume such as myocarditis, diffuse myocardial fibrosis and amyloidosis, and is a promising diagnostic tool for patients with iron overload and Fabry disease...
January 28, 2017: World Journal of Radiology
https://www.readbyqxmd.com/read/28113417/enhancing-the-velocity-data-from-4d-flow-mr-images-by-reducing-its-divergence
#10
Joaquin Mura, A Matias Pino, Julio Sotelo, Israel Valverde, Cristian Tejos, Marcelo Andia, Pablo Irarrazaval, Sergio Uribe
Velocity measurements from 4D flow MRI are prone to be affected by several imperfections of the MR system. Assuming that blood is incompressible, we propose a novel method for enhancing the velocity field by reducing its divergence. To enhance the velocity data, we added a corrector velocity to each voxel such that the divergence is minimized. The method was validated using an analytical Womersley flow model for different settings of resolution and noise levels. The performance of the proposed method was also assessed in volunteers and patients...
May 18, 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28074541/comparison-of-respiratory-motion-suppression-techniques-for-4d-flow-mri
#11
Petter Dyverfeldt, Tino Ebbers
PURPOSE: The purpose of this work was to assess the impact of respiratory motion and to compare methods for suppression of respiratory motion artifacts in 4D Flow MRI. METHODS: A numerical 3D aorta phantom was designed based on an aorta velocity field obtained by computational fluid mechanics. Motion-distorted 4D Flow MRI measurements were simulated and several different motion-suppression techniques were evaluated: Gating with fixed acceptance window size, gating with different window sizes in inner and outer k-space, and k-space reordering...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28057635/in-vivo-assessment-of-the-impact-of-regional-intracranial-atherosclerotic-lesions-on-brain-arterial-3d-hemodynamics
#12
C Wu, S Schnell, P Vakil, A R Honarmand, S A Ansari, J Carr, M Markl, S Prabhakaran
BACKGROUND AND PURPOSE: Intracranial atherosclerosis induces hemodynamic disturbance, which is not well-characterized, particularly in cerebral flow redistribution. We aimed to characterize the impact of regional stenotic lesions on intracranial hemodynamics by using 4D flow MR imaging. MATERIALS AND METHODS: 4D flow MR imaging was performed in 22 symptomatic patients (mean age, 68.4 ± 14.2 years) with intracranial stenosis (ICA, n = 7; MCA, n = 9; basilar artery, n = 6) and 10 age-appropriate healthy volunteers (mean age, 60...
January 5, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28048777/mo-e-brb-00-panel-discussion-sbrt-srs-case-studies-lung
#13
Stanley Benedict
: In this interactive session, lung SBRT patient cases will be presented to highlight real-world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss challenges specific to lung SBRT including patient selection, patient immobilization techniques, 4D CT simulation and respiratory motion management, target delineation for treatment planning, online treatment alignment, and established prescription regimens and OAR dose limits. Practical examples of cases, including the patient flow thought the clinical process are presented and audience participation will be encouraged...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048757/mo-e-brb-01-panel-member
#14
S Benedict
: In this interactive session, lung SBRT patient cases will be presented to highlight real-world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss challenges specific to lung SBRT including patient selection, patient immobilization techniques, 4D CT simulation and respiratory motion management, target delineation for treatment planning, online treatment alignment, and established prescription regimens and OAR dose limits. Practical examples of cases, including the patient flow thought the clinical process are presented and audience participation will be encouraged...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048100/su-f-t-91-development-of-real-time-abdominal-compression-force-acf-monitoring-system
#15
T Kim, S Kim, D Kim, S Kang, M Cho, K Kim, D Shin, Y Noh, T Suh
PURPOSE: Hard-plate based abdominal compression is known to be effective, but no explicit method exists to quantify abdominal compression force (ACF) and maintain the proper ACF through the whole procedure. In addition, even with compression, it is necessary to do 4D CT to manage residual motion but, 4D CT is often not possible due to reduced surrogating sensitivity. In this study, we developed and evaluated a system that both monitors ACF in real time and provides surrogating signal even under compression...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048099/mo-e-brb-02-panel-member
#16
J Larner
: In this interactive session, lung SBRT patient cases will be presented to highlight real-world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss challenges specific to lung SBRT including patient selection, patient immobilization techniques, 4D CT simulation and respiratory motion management, target delineation for treatment planning, online treatment alignment, and established prescription regimens and OAR dose limits. Practical examples of cases, including the patient flow thought the clinical process are presented and audience participation will be encouraged...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048061/mo-fg-campus-jep2-01-4d-mri-with-3d-radial-sampling-and-self-gating-based-k-space-sorting-image-quality-improvement-by-slab-selective-excitation
#17
Z Deng, W Yang, J Pang, R Tuli, X Bi, B Hakimian, B Fraass, D Li, Z Fan
PURPOSE: A recent 4D MRI technique based on 3D radial sampling and self-gating-based K-space sorting has shown promising results in characterizing respiratory motion. However due to continuous acquisition and potentially drastic k-space undersampling resultant images could suffer from low blood-to-tissue contrast and streaking artifacts. In this study 3D radial sampling with slab-selective excitation (SS) was proposed in attempt to enhance blood-to-tissue contrast by exploiting the in-flow effect and to suppress the excess signal from the peripheral structures particularly in the superior-inferior direction...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047932/tu-h-campus-iep3-02-neurovascular-4d-parametric-imaging-using-co-registration-of-biplane-dsa-sequences-with-3d-vascular-geometry-obtained-from-cone-beam-ct
#18
A Balasubramoniam, D Bednarek, S Rudin, C Ionita
PURPOSE: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). METHODS: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047708/th-cd-207a-05-lung-surface-deformation-vector-fields-prediction-by-monitoring-respiratory-surrogate-signals
#19
J Nasehi Tehrani, A McEwan, J Wang
PURPOSE: In this study, we developed and evaluated a method for predicting lung surface deformation vector fields (SDVFs) based on surrogate signals such as chest and abdomen motion at selected locations and spirometry measurements. METHODS: A Patient-specific 3D triangular surface mesh of the lung region at end-expiration (EE) phase was obtained by threshold-based segmentation method. For each patient, a spirometer recorded the flow volume changes of the lungs; and 192 selected points at a regular spacing of 2cm X 2cm matrix points over a total area of 34cm X 24cm on the surface of chest and abdomen was used to detect chest wall motions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047441/mo-e-brb-03-panel-member
#20
B Salter
: In this interactive session, lung SBRT patient cases will be presented to highlight real-world considerations for ensuring safe and accurate treatment delivery. An expert panel of speakers will discuss challenges specific to lung SBRT including patient selection, patient immobilization techniques, 4D CT simulation and respiratory motion management, target delineation for treatment planning, online treatment alignment, and established prescription regimens and OAR dose limits. Practical examples of cases, including the patient flow thought the clinical process are presented and audience participation will be encouraged...
June 2016: Medical Physics
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