scholarly journals k-t GRAPPA accelerated four-dimensional flow MRI in the aorta: Effect on scan time, image quality, and quantification of flow and wall shear stress

2013 ◽  
Vol 72 (2) ◽  
pp. 522-533 ◽  
Author(s):  
Susanne Schnell ◽  
Michael Markl ◽  
Pegah Entezari ◽  
Riti J. Mahadewia ◽  
Edouard Semaan ◽  
...  
Keyword(s):  
Shear Stress ◽  
Image Quality ◽  
Wall Shear Stress ◽  
Dimensional Flow ◽  
Scan Time ◽  
Flow Mri ◽  
Wall Shear ◽  
Time Image

scholarly journals A methodology to detect abnormal relative wall shear stress on the full surface of the thoracic aorta using four-dimensional flow MRI

2014 ◽  
Vol 73 (3) ◽  
pp. 1216-1227 ◽  
Author(s):  
Pim van Ooij ◽  
Wouter V. Potters ◽  
Aart J. Nederveen ◽  
Bradley D. Allen ◽  
Jeremy Collins ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Thoracic Aorta ◽  
Dimensional Flow ◽  
Flow Mri ◽  
Wall Shear

scholarly journals Two-Minute k-Space and Time–accelerated Aortic Four-dimensional Flow MRI: Dual-Center Study of Feasibility and Impact on Velocity and Wall Shear Stress Quantification

2019 ◽  
Vol 1 (2) ◽  
pp. e180008 ◽  
Author(s):  
Emilie Bollache ◽  
Kristopher D. Knott ◽  
Kelly Jarvis ◽  
Redha Boubertakh ◽  
Ryan Scott Dolan ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Dimensional Flow ◽  
Space And Time ◽  
Flow Mri ◽  
Wall Shear ◽  
Center Study

scholarly journals Normal patterns of thoracic aortic wall shear stress measured using four-dimensional flow MRI in a large population

2018 ◽  
Vol 315 (5) ◽  
pp. H1174-H1181 ◽  
Author(s):  
Fraser M. Callaghan ◽  
Stuart M. Grieve
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Temporal Variation ◽  
Aortic Arch ◽  
Anterior Wall ◽  
Spatial And Temporal Variation ◽  
Descending Aorta ◽  
Dimensional Flow ◽  
Flow Mri ◽  
Wall Shear

Wall shear stress (WSS) plays a governing role in vascular remodeling and a pathogenic role in vessel wall diseases. However, little is known of the normal WSS patterns in the aorta as there is currently no practical means to routinely measure WSS and no normal ranges derived from population data exist. WSS measurements were made on the aorta of 224 subjects with normal anatomy using four-dimensional flow MRI with multiple encoding velocities and an optimized postprocessing routine. The spatial and temporal variation in WSS and oscillatory shear index was analyzed using a flat map representation of the unfolded aorta. The influence of aortic shape and velocity on WSS was evaluated using regression analysis. WSS in the thoracic aorta is dominated by axial flow. Average peak systolic WSS was 1.79 ± 0.71 Pa in the aortic arch and was significantly higher at 2.23 ± 1.04 Pa in the descending aorta, with a strong negative correlation with advancing age. The spatial distribution of WSS is highly heterogeneous, with a localized region of elevated WSS along the length of the anterior wall seen across all individuals. Our data demonstrate that accurate four-dimensional flow-derived WSS measurement is feasible, and we further provide a standardized parametric approach for presentation and analysis. We present a normal range for WSS across the lifespan, demonstrating a decrease in WSS with advancing age as well as illustrating the high degree of spatial and temporal variation. NEW & NOTEWORTHY With the use of four-dimensional flow MRI and postprocessing, accurate direct measurement of wall shear stress (WSS) was performed in a population of normal thoracic aortas ( n = 224). WSS was higher in the descending aorta compared with the aortic arch and decreased with age. A heterogeneous pattern of elevated WSS along the length of the aorta anterior wall was consistent across the population. This work provides normal data across the adult age range, permitting comparison with pathology.

scholarly journals Comprehensive mechanical & metabolic imaging of abdominal aortic aneurysm with 4D flow/ FDG PET on an integrated PETMRI: a feasibility study

2021 ◽  
Vol 22 (Supplement_3) ◽  
Author(s):  
S Wan ◽  
J Steeden ◽  
M Rega ◽  
L Hoy ◽  
D Walls ◽  
...  
Keyword(s):  
Shear Stress ◽  
Abdominal Aortic Aneurysm ◽  
Image Quality ◽  
Aortic Aneurysm ◽  
Wall Shear Stress ◽  
Fdg Pet ◽  
Metabolic Imaging ◽  
Research Centre ◽  
Abdominal Aortic ◽  
Wall Shear

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): NIHR Biomedical Research Centre, University College London Hospitals. Background A number of non-invasive imaging derived parameters have been implicated in the development and progression of abdominal aortic aneurysm, although the mechanism, and relationships of many of these are yet to be precisely determined.  Mechanical parameters can now be studied using 4D phase contrast magnetic resonance (PCMR), and inflammatory cellular activity can be detected with FDG PET. Purpose It may be postulated that inflammation of the aortic wall may be the intermediary at the tissue level linking mechanical wall shear stress (WSS) to aneurysm progression. It may be feasible to study 4D PCMR and FDG PET at the same patient visit on a PETMRI platform, with the potential to enhance temporal and spatial co-registration and improving the understanding of any relationship between these two parameters.  Our study aims to assess feasibility of studying these on an integrated PETMRI system. Methods 7 patients with known aortic aneurysm were recruited in a vascular ultrasound screening follow up clinic.  During a single visit following 6 hours fasting, all patients underwent FDG injection and 60 minutes uptake period.  With quiet breathing, list mode PET acquisition and concurrent 4D PCMR was acquired using stacks of spiral acquisition, with ECG trace information for retrospective gating.  Images from the 4D PCMR and FDG PET were assessed qualitatively for image quality and visual matching. Results All 7 patients completed the study.  Overall image quality was adequate to good.  There is qualitatively a good concordance with impression of positive correlation between wall shear stress and inflammatory signal (see attached image). Conclusion We have demonstrated feasibility of combined assessment of mechanical and metabolic imaging parameters using an integrated PETMRI system.  Initial findings show there to be a broad concordance of wall shear stress and inflammatory signal in the abdominal aneurysm.

scholarly journals Volumetric segmentation-free method for rapid visualization of vascular wall shear stress using 4D flow MRI

2018 ◽  
Vol 80 (2) ◽  
pp. 748-755 ◽  
Author(s):  
Evan M. Masutani ◽  
Francisco Contijoch ◽  
Espoir Kyubwa ◽  
Joseph Cheng ◽  
Marcus T. Alley ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Vascular Wall ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri ◽  
Wall Shear ◽  
Volumetric Segmentation

scholarly journals 4-D flow MRI aortic 3-D hemodynamics and wall shear stress remain stable over short-term follow-up in pediatric and young adult patients with bicuspid aortic valve

2018 ◽  
Vol 49 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Michael J. Rose ◽  
Cynthia K. Rigsby ◽  
Haben Berhane ◽  
Emilie Bollache ◽  
Kelly Jarvis ◽  
...  
Keyword(s):  
Shear Stress ◽  
Young Adult ◽  
Aortic Valve ◽  
Wall Shear Stress ◽  
Bicuspid Aortic Valve ◽  
Adult Patients ◽  
Short Term ◽  
Flow Mri ◽  
Wall Shear

scholarly journals On the ‘cusp’ of clinical feasibility: aortic wall shear stress derived non-invasively with 4D flow MRI

2019 ◽  
Vol 11 (7) ◽  
pp. E96-E97
Author(s):  
Emilie Bollache ◽  
Paul W. M. Fedak ◽  
Michael Markl ◽  
Alex J. Barker
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Aortic Wall ◽  
4D Flow Mri ◽  
4D Flow ◽  
Flow Mri ◽  
Wall Shear

Abstract 14689: Regional Aortic Wall Shear Stress Mapping Implicates Hemodynamics in Human Bicuspid Aortopathy

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
David G Guzzardi ◽  
Pim van Ooij ◽  
Alex J Barker ◽  
Giampaolo Martufi ◽  
Katherine E Olsen ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Aortic Wall ◽  
Transforming Growth Factor ◽  
Patient Specific ◽  
4D Flow Mri ◽  
4D Flow ◽  
Hemodynamic Assessment ◽  
Flow Mri ◽  
Wall Shear

Introduction: A suspected genetic cause for bicuspid aortic valve (BAV) aortopathy has led to aggressive resection strategies. Using 4D flow MRI, we documented increased regional wall shear stress (WSS) in BAV patients. Local hemodynamics may exacerbate extracellular matrix (ECM) degradation leading to disease progression. If validated, preoperative regional hemodynamic assessment could be used to guide more targeted patient-specific aortic resection. For the first time, we correlated regional WSS with aortic tissue remodeling in BAV patients. Methods & Results: BAV patients (N=11) undergoing ascending aortic resection received preoperative 4D flow MRI with regional WSS differences mapped. Paired aortic wall samples (from same-patient with elevated WSS paired to normal WSS regions) were collected during surgery and compared using histology (pentachrome), biomechanics (biaxial mechanical testing), and ECM regulation (protein expression). Patient mean age: 49±18 years; mean aortic diameter: 4.6±0.7cm (range: 3.6 - 6.3cm); 55% had R+L fusion pattern; 36% had severe aortic stenosis. All patients had heterogeneous WSS patterns with regions of elevated WSS adjacent to those of normal WSS. By histology, regions of increased WSS showed greater medial elastin fragmentation, fibrosis, and cystic medial necrosis compared to adjacent areas of normal WSS. Regions of increased WSS showed increased elastic modulus (fold change±SD: 1.53±0.68; P=0.06, N=5) and collagen stiffness (1.37±0.49; P=0.07, N=5) compared to normal WSS regions suggesting altered distensibility. Multiplex protein analyses of ECM regulatory molecules revealed an increase in transforming growth factor β-1 (1.49±0.71, P=0.02), MMP-1 (1.62±0.84; P=0.01), MMP-2 (1.49±1.00; P=0.06), MMP-3 (1.23±0.36; P=0.02), MMP-7 (1.57±0.75; P=0.02), and TIMP-2 (1.26±0.33; P=0.01) in elevated WSS regions suggesting ECM dysregulation consistent with aortic remodeling. Conclusions: In BAV aorta, regional WSS corresponds with local histologic abnormalities, altered biomechanics, and ECM dysregulation. These novel data strongly implicate local hemodynamics as a mediator of BAV aortopathy. With further validation, 4D flow MRI could be used to guide personalized resection strategies.

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