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4D Flow

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https://www.readbyqxmd.com/read/28425452/estimating-the-irreversible-pressure-drop-across-a-stenosis-by-quantifying-turbulence-production-using-4d-flow-mri
#1
Hojin Ha, Jonas Lantz, Magnus Ziegler, Belen Casas, Matts Karlsson, Petter Dyverfeldt, Tino Ebbers
The pressure drop across a stenotic vessel is an important parameter in medicine, providing a commonly used and intuitive metric for evaluating the severity of the stenosis. However, non-invasive estimation of the pressure drop under pathological conditions has remained difficult. This study demonstrates a novel method to quantify the irreversible pressure drop across a stenosis using 4D Flow MRI by calculating the total turbulence production of the flow. Simulation MRI acquisitions showed that the energy lost to turbulence production can be accurately quantified with 4D Flow MRI within a range of practical spatial resolutions (1-3 mm; regression slope = 0...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28416516/semaphorin-4d-inhibits-neutrophil-activation-and-is-involved-in-the-pathogenesis-of-neutrophil-mediated-autoimmune-vasculitis
#2
Masayuki Nishide, Satoshi Nojima, Daisuke Ito, Hyota Takamatsu, Shohei Koyama, Sujin Kang, Tetsuya Kimura, Keiko Morimoto, Takashi Hosokawa, Yoshitomo Hayama, Yuhei Kinehara, Yasuhiro Kato, Takeshi Nakatani, Yoshimitsu Nakanishi, Takeshi Tsuda, Jeong Hoon Park, Toru Hirano, Yoshihito Shima, Masashi Narazaki, Eiichi Morii, Atsushi Kumanogoh
OBJECTIVES: Inappropriate activation of neutrophils plays a pathological role in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The aim of this study was to investigate the functions of semaphorin 4D (SEMA4D) in regulation of neutrophil activation, and its involvement in AAV pathogenesis. METHODS: Serum levels of soluble SEMA4D were evaluated by ELISA. Blood cell-surface expression of membrane SEMA4D was evaluated by flow cytometry. To determine the functional interactions between neutrophil membrane SEMA4D and endothelial plexin B2, wild-type and SEMA4D(-/-) mice neutrophils were cultured with an endothelial cell line (MS1) stained with SYTOX green, and subjected to neutrophil extracellular trap (NET) formation assays...
April 17, 2017: Annals of the Rheumatic Diseases
https://www.readbyqxmd.com/read/28401632/role-of-four-dimensional-echocardiography-with-high-definition-flow-imaging-and-spatiotemporal-image-correlation-in-detecting-fetal-pulmonary-veins
#3
Xue Sun, Ying Zhang, Miao Fan, Yu Wang, Meilian Wang, Faiza Amber Siddiqui, Wei Sun, Feifei Sun, Dongyu Zhang, Wenjia Lei, Guyue Hu
BACKGROUND: Prenatal diagnosis of fetal total anomalous pulmonary vein connection (TAPVC) remains challenging for most screening sonographers. The purpose of this study was to evaluate the use of four-dimensional echocardiography with high-definition flow imaging and spatiotemporal image correlation (4D-HDFI) in identifying pulmonary veins in normal and TAPVC fetuses. MATERIAL & METHODS: We retrospectively reviewed and performed 4D-HDFI in 204 normal and 12 fetuses with confirmed diagnosis of TAPVC...
April 12, 2017: Echocardiography
https://www.readbyqxmd.com/read/28386716/importance-of-variants-in-cerebrovascular-anatomy-for-potential-retrograde-embolization-in-cryptogenic-stroke
#4
Michael Markl, Edouard Semaan, LeRoy Stromberg, James Carr, Shyam Prabhakaran, Jeremy Collins
OBJECTIVES: To test the hypothesis that variants in cerebrovascular anatomy will affect the number of patients demonstrating a plausible retrograde embolization mechanism from plaques in the descending aorta (DAo). METHODS: Thirty-five patients (aged 63 ± 17 years) with cryptogenic stroke underwent 4D flow MRI for the assessment of aortic 3D blood flow and MR angiography for the evaluation of circle of Willis, posterior circulation, and aortic arch architecture...
April 6, 2017: European Radiology
https://www.readbyqxmd.com/read/28367905/4d-flow-mr-imaging-of-ophthalmic-artery-flow-in-patients-with-internal-carotid-artery-stenosis
#5
Tetsuro Sekine, Ryo Takagi, Yasuo Amano, Yasuo Murai, Erika Orita, Yoshimitsu Fukushima, Yoshio Matsumura, Shin-Ichiro Kumita
BACKGROUND AND PURPOSE: To assess the clinical feasibility of time-resolved three-dimensional phase contrast (4D Flow) magnetic resonance imaging (MRI) assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS). MATERIALS AND METHODS: Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28366753/the-position-and-role-of-4d-cta-in-the-diagnosis-and-treatment-of-spinal-arteriovenous-fistulas
#6
Satoshi Yamaguchi, Kohei Takemoto, Masaaki Takeda, Yosuke Kajihara, Takafumi Mitsuhara, Manish Kolakshyapati, Kazutoshi Mukada, Kaoru Kurisu
BACKGROUND: Localization of the arteriovenous fistula (AVF) is a crucial step in the diagnosis and treatment of spinal vascular malformations (VMs). Non-invasive angiographic techniques such as dynamic magnetic resonance angiography (MRA) and 3-dimensional computed tomography angiography (3D-CTA) have been used as standard modalities to localize AVF. With the increasing prevalence of high-spec CT scanner, 4D-CTA is being increasingly utilized in the evaluation of cerebrovascular disorders...
March 30, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28366054/advanced-imaging-in-acute-ischemic-stroke
#7
Craig Kilburg, J Scott McNally, Adam de Havenon, Philipp Taussky, M Yashar S Kalani, Min S Park
The evaluation and management of acute ischemic stroke has primarily relied on the use of conventional CT and MRI techniques as well as lumen imaging sequences such as CT angiography (CTA) and MR angiography (MRA). Several newer or less-established imaging modalities, including vessel wall MRI, transcranial Doppler ultrasonography, and 4D CTA and MRA, are being developed to complement conventional CT and MRI techniques. Vessel wall MRI provides high-resolution analysis of both extracranial and intracranial vasculature to help identify previously occult lesions or characteristics of lesions that may portend a worse natural history...
April 2017: Neurosurgical Focus
https://www.readbyqxmd.com/read/28359292/cardiac-4d-phase-contrast-cmr-at-9-4%C3%A2-t-using-self-gated-ultra-short-echo-time-ute-imaging
#8
M Krämer, A G Motaal, K-H Herrmann, B Löffler, J R Reichenbach, G J Strijkers, V Hoerr
BACKGROUND: Time resolved 4D phase contrast (PC) cardiovascular magnetic resonance (CMR) in mice is challenging due to long scan times, small animal ECG-gating and the rapid blood flow and cardiac motion of small rodents. To overcome several of these technical challenges we implemented a retrospectively self-gated 4D PC radial ultra-short echo-time (UTE) acquisition scheme and assessed its performance in healthy mice by comparing the results with those obtained with an ECG-triggered 4D PC fast low angle shot (FLASH) sequence...
March 31, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28327193/longitudinal-evaluation-of-aortic-hemodynamics-in-marfan-syndrome-new-insights-from-a-4d-flow-cardiovascular-magnetic-resonance-multi-year-follow-up-study
#9
Julia Geiger, Daniel Hirtler, Kristina Gottfried, Ozair Rahman, Emilie Bollache, Alex J Barker, Michael Markl, Brigitte Stiller
BACKGROUND: The aim of this 4D flow cardiovascular magnetic resonance (CMR) follow-up study was to investigate longitudinal changes in aortic hemodynamics in adolescent patients with Marfan syndrome (MFS). METHODS: 4D flow CMR for the assessment of in-vivo 3D blood flow with full coverage of the thoracic aorta was performed twice (baseline scan t1/follow-up scan t2) in 19 adolescent MFS patients (age at t1: 12.7 ± 3.6 years, t2: 16.2 ± 4.3 years) with a mean follow-up duration of 3...
March 22, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28317480/novel-insights-into-complex-cardiovascular-pathologies-using-4d-flow-analysis-by-cardiovascular-magnetic-resonance-imaging
#10
Adam James Lewandowski, Betty Raman, Rajarshi Banerjee, Matteo Milanesi
BACKGROUND: It is essential that we are able to assess variations in blood flow in order to fully understand cardiovascular function in disease pathologies and for identification of individuals at long-term risk of cardiovascular disease development. Qualitative and quantitative assessments of blood flow by imaging modalities have been limited, and much of the accurate quantification has relied on invasive measures. METHODS: This review discusses how four-dimensional velocity cardiovascular magnetic resonance (4D flow CMR) offers increasing potential for the non-invasive assessment of blood flow in the heart and major blood vessels such as the aorta...
March 17, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28302143/altered-aortic-3d-hemodynamics-and-geometry-in-pediatric-marfan-syndrome-patients
#11
Roel L F van der Palen, Alex J Barker, Emilie Bollache, Julio Garcia, Michael J Rose, Pim van Ooij, Luciana T Young, Arno A W Roest, Michael Markl, Joshua D Robinson, Cynthia K Rigsby
BACKGROUND: Blood flow dynamics make it possible to better understand the development of aortopathy and cardiovascular events in patients with Marfan syndrome (MFS). Aortic 3D blood flow characteristics were investigated in relation to aortic geometry in children and adolescents with MFS. METHODS: Twenty-five MFS patients (age 15.6 ± 4.0 years; 11 females) and 21 healthy controls (age 16.0 ± 2.6 years; 12 females) underwent magnetic resonance angiography and 4D flow CMR for assessment of thoracic aortic size and 3D blood flow velocities...
March 17, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28295788/creating-hemodynamic-atlases-of-cardiac-4d-flow-mri
#12
Merih Cibis, Mariana Bustamante, Jonatan Eriksson, Carl-Johan Carlhäll, Tino Ebbers
PURPOSE: Hemodynamic atlases can add to the pathophysiological understanding of cardiac diseases. This study proposes a method to create hemodynamic atlases using 4D Flow magnetic resonance imaging (MRI). The method is demonstrated for kinetic energy (KE) and helicity density (Hd ). MATERIALS AND METHODS: Thirteen healthy subjects underwent 4D Flow MRI at 3T. Phase-contrast magnetic resonance cardioangiographies (PC-MRCAs) and an average heart were created and segmented...
March 13, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28282389/4d-flow-mri-assessment-of-right-atrial-flow-patterns-in-the-normal-heart-influence-of-caval-vein-arrangement-and-implications-for-the-patent-foramen-ovale
#13
Jehill D Parikh, Jayant Kakarla, Bernard Keavney, John J O'Sullivan, Gary A Ford, Andrew M Blamire, Kieren G Hollingsworth, Louise Coats
AIM: To investigate atrial flow patterns in the normal adult heart, to explore whether caval vein arrangement and patency of the foramen ovale (PFO) may be associated with flow pattern. MATERIALS AND METHODS: Time-resolved, three-dimensional velocity encoded magnetic resonance imaging (4D flow) was employed to assess atrial flow patterns in thirteen healthy subjects (6 male, 40 years, range 25-50) and thirteen subjects (6 male, 40 years, range 21-50) with cryptogenic stroke and patent foramen ovale (CS-PFO)...
2017: PloS One
https://www.readbyqxmd.com/read/28273332/comparison-between-model-predicted-tumor-oxygenation-dynamics-and-vascular-flow-related-doppler-indices
#14
Antonella Belfatto, Ailyn M Vidal Urbinati, Delia Ciardo, Dorella Franchi, Federica Cattani, Roberta Lazzari, Barbara A Jereczek-Fossa, Roberto Orecchia, Guido Baroni, Pietro Cerveri
PURPOSE: Mathematical modeling is a powerful and flexible method to investigate complex phenomena. It discloses the possibility of reproducing expensive as well as invasive experiments in a safe environment with limited costs. This makes it suitable to mimic tumor evolution and response to radiotherapy although the reliability of the results remains an issue. Complexity reduction is therefore a critical aspect in order to be able to compare model outcomes to clinical data. Among the factors affecting treatment efficacy, tumor oxygenation is known to play a key role in radiotherapy response...
March 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28271159/inflow-hemodynamics-evaluated-by-using-four-dimensional-flow-magnetic-resonance-imaging-and-the-size-ratio-of-unruptured-cerebral-aneurysms
#15
Kazuya Futami, Iku Nambu, Tomohiro Kitabayashi, Hiroki Sano, Kouichi Misaki, Naoyuki Uchiyama, Mitsutoshi Nakada
PURPOSE: Prediction of the rupture risk is critical for the identification of unruptured cerebral aneurysms (UCAs) eligible for invasive treatments. The size ratio (SR) is a strong morphological predictor for rupture. We investigated the relationship between the inflow hemodynamics evaluated on four-dimensional (4D) flow magnetic resonance (MR) imaging and the SR to identify specific characteristics related to UCA rupture. METHODS: We evaluated the inflow jet patterns and inflow hemodynamic parameters of 70 UCAs on 4D flow MR imaging and compared them among 23 aneurysms with an SR ≧2...
March 7, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28268560/4d-lung-tumor-segmentation-via-shape-prior-and-motion-cues
#16
Jung Won Cha, Mohammad M Farhangi, Neal Dunlap, Amir Amini
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/28266062/k-t-accelerated-aortic-4d-flow-mri-in-under-two-minutes-feasibility-and-impact-of-resolution-k-space-sampling-patterns-and-respiratory-navigator-gating-on-hemodynamic-measurements
#17
Emilie Bollache, Alex J Barker, Ryan Scott Dolan, James C Carr, Pim van Ooij, Rouzbeh Ahmadian, Alex Powell, Jeremy D Collins, Julia Geiger, Michael Markl
PURPOSE: To assess the performance of highly accelerated free-breathing aortic four-dimensional (4D) flow MRI acquired in under 2 minutes compared to conventional respiratory gated 4D flow. METHODS: Eight k-t accelerated nongated 4D flow MRI (parallel MRI with extended and averaged generalized autocalibrating partially parallel acquisition kernels [PEAK GRAPPA], R = 5, TRes = 67.2 ms) using four ky -kz Cartesian sampling patterns (linear, center-out, out-center-out, random) and two spatial resolutions (SRes1 = 3...
March 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28242061/patient-specific-in-vitro-models-for-hemodynamic-analysis-of-congenital-heart-disease-additive-manufacturing-approach
#18
Rafael Medero, Sylvana García-Rodríguez, Christopher J François, Alejandro Roldán-Alzate
Non-invasive hemodynamic assessment of total cavopulmonary connection (TCPC) is challenging due to the complex anatomy. Additive manufacturing (AM) is a suitable alternative for creating patient-specific in vitro models for flow measurements using four-dimensional (4D) Flow MRI. These in vitro systems have the potential to serve as validation for computational fluid dynamics (CFD), simulating different physiological conditions. This study investigated three different AM technologies, stereolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM), to determine differences in hemodynamics when measuring flow using 4D Flow MRI...
February 7, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28239641/macrovascular-and-microvascular-cerebral-blood-flow-in-adults-at-risk-for-alzheimer-s-disease
#19
Lindsay R Clark, Sara E Berman, Leonardo A Rivera-Rivera, Siobhan M Hoscheidt, Burcu F Darst, Corinne D Engelman, Howard A Rowley, Cynthia M Carlsson, Sanjay Asthana, Patrick Turski, Oliver Wieben, Sterling C Johnson
INTRODUCTION: Capillary hypoperfusion is reported in asymptomatic adults at-risk for Alzheimer's disease (AD), but the extent that can be explained by reduced flow in intracranial arteries is unknown. METHODS: One hundred fifty-five asymptomatic adults enriched for AD risk (mean age 61 years) completed arterial spin labeling (pcASL) and 4D-flow MRI sequences. Voxel-wise regression models investigated the relationship between mean flow in bilateral cerebral arteries and capillary perfusion, and tested potential moderators of this relationship...
2017: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring
https://www.readbyqxmd.com/read/28226737/4d-lung-tumor-segmentation-via-shape-prior-and-motion-cues
#20
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
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