Enhancement of cerebrovascular 4D flow MRI velocity fields using machine learning and computational fluid dynamics simulation data

AbstractBlood flow metrics obtained with four-dimensional (4D) flow phase contrast (PC) magnetic resonance imaging (MRI) can be of great value in clinical and experimental cerebrovascular analysis. However, limitations in both quantitative and qualitative analyses can result from errors inherent to PC MRI. One method that excels in creating low-error, physics-based, velocity fields is computational fluid dynamics (CFD). Augmentation of cerebral 4D flow MRI data with CFD-informed neural networks may provide a method to produce highly accurate physiological flow fields. In this preliminary study, the potential utility of such a method was demonstrated by using high resolution patient-specific CFD data to train a convolutional neural network, and then using the trained network to enhance MRI-derived velocity fields in cerebral blood vessel data sets. Through testing on simulated images, phantom data, and cerebrovascular 4D flow data from 20 patients, the trained network successfully de-noised flow images, decreased velocity error, and enhanced near-vessel-wall velocity quantification and visualization. Such image enhancement can improve experimental and clinical qualitative and quantitative cerebrovascular PC MRI analysis.

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Multi-modality cerebral aneurysm haemodynamic analysis: in vivo 4D flow MRI, in vitro volumetric particle velocimetry and in silico computational fluid dynamics

Journal of The Royal Society Interface ◽

10.1098/rsif.2019.0465 ◽

2019 ◽

Vol 16 (158) ◽

pp. 20190465 ◽

Cited By ~ 3

Author(s):

Melissa C. Brindise ◽

Sean Rothenberger ◽

Benjamin Dickerhoff ◽

Susanne Schnell ◽

Michael Markl ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Cerebral Aneurysm ◽

Patient Specific ◽

4D Flow Mri ◽

4D Flow ◽

Relative Residence Time ◽

Flow Mri

Typical approaches to patient-specific haemodynamic studies of cerebral aneurysms use image-based computational fluid dynamics (CFD) and seek to statistically correlate parameters such as wall shear stress (WSS) and oscillatory shear index (OSI) to risk of growth and rupture. However, such studies have reported contradictory results, emphasizing the need for in-depth multi-modality haemodynamic metric evaluation. In this work, we used in vivo 4D flow MRI data to inform in vitro particle velocimetry and CFD modalities in two patient-specific cerebral aneurysm models (basilar tip and internal carotid artery). Pulsatile volumetric particle velocimetry experiments were conducted, and the particle images were processed using Shake-the-Box, a particle tracking method. Distributions of normalized WSS and relative residence time were shown to be highly yet inconsistently affected by minor flow field and spatial resolution variations across modalities, and specific relationships among these should be explored in future work. Conversely, OSI, a non-dimensional parameter, was shown to be more robust to the varying assumptions, limitations and spatial resolutions of each subject and modality. These results suggest a need for further multi-modality analysis as well as development of non-dimensional haemodynamic parameters and correlation of such metrics to aneurysm risk of growth and rupture.

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Hemodynamic Study of a Patient-Specific Intracranial Aneurysm: Comparative Assessment of Tomographic PIV, Stereoscopic PIV, In Vivo MRI and Computational Fluid Dynamics

Cardiovascular Engineering and Technology ◽

10.1007/s13239-021-00583-2 ◽

2021 ◽

Author(s):

Xiaolin Wu ◽

Stefanie Gürzing ◽

Christiaan Schinkel ◽

Merel Toussaint ◽

Romana Perinajová ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Intracranial Aneurysm ◽

Comparative Assessment ◽

Patient Specific ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri

Abstract Introduction Wall shear stress (WSS) is associated with the growth and rupture of an intracranial aneurysm. To reveal their underlying connections, many image-based computational fluid dynamics (CFD) studies have been conducted. However, the methodological validations using both in vivo medical imaging and in vitro optical flow measurements were rarely accompanied in such studies. Methods In the present study, we performed a comparative assessment on the hemodynamics of a patient-specific intracranial saccular aneurysm using in vivo 4D Flow MRI, in silico CFD, in vitro stereoscopic and tomographic particle imaging velocimetry (Stereo-PIV and Tomo-PIV) techniques. PIV experiments and CFD were conducted under steady state corresponding to the peak systole of 4D Flow MRI. Results The results showed that all modalities provided similar flow features and overall surface distribution of WSS. However, a large variation in the absolute WSS values was found. 4D Flow MRI estimated a 2- to 4-fold lower peak WSS (3.99 Pa) and a 1.6- to 2-fold lower mean WSS (0.94 Pa) than Tomo-PIV, Stereo-PIV, and CFD. Bland-Altman plots of WSS showed that the differences between PIV-/CFD-based WSS and 4D Flow MRI-based WSS increase with higher WSS magnitude. Such proportional trend was absent in the Bland-Altman comparison of velocity where the resolutions of PIV and CFD datasets were matched to 4D Flow MRI. We also found that because of superior resolution in the out-of-plane direction, WSS estimation by Tomo-PIV was higher than Stereo-PIV. Conclusions Our results indicated that the differences in spatial resolution could be the main contributor to the discrepancies between each modality. The findings of this study suggest that with current techniques, care should be taken when using absolute WSS values to perform a quantitative risk analysis of aneurysm rupture.

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Thoracic aortic aneurysm: 4D flow MRI and computational fluid dynamics model

Computer Methods in Biomechanics & Biomedical Engineering ◽

10.1080/10255842.2015.1069559 ◽

2015 ◽

Vol 18 (sup1) ◽

pp. 1894-1895 ◽

Cited By ~ 15

Author(s):

F. M. Callaghan ◽

J. Karkouri ◽

K. Broadhouse ◽

M. Evin ◽

D. F. Fletcher ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Aortic Aneurysm ◽

Thoracic Aortic Aneurysm ◽

Dynamics Model ◽

4D Flow Mri ◽

4D Flow ◽

Computational Fluid Dynamics Model ◽

Flow Mri

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The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics

Journal of Biomechanics ◽

10.1016/j.jbiomech.2015.07.039 ◽

2015 ◽

Vol 48 (12) ◽

pp. 2984-2989 ◽

Cited By ~ 24

Author(s):

Merih Cibis ◽

Kelly Jarvis ◽

Michael Markl ◽

Michael Rose ◽

Cynthia Rigsby ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Viscous Dissipation ◽

Fontan Circulation ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri

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4DFlowNet: Super-Resolution 4D Flow MRI Using Deep Learning and Computational Fluid Dynamics

Frontiers in Physics ◽

10.3389/fphy.2020.00138 ◽

2020 ◽

Vol 8 ◽

Cited By ~ 1

Author(s):

Edward Ferdian ◽

Avan Suinesiaputra ◽

David J. Dubowitz ◽

Debbie Zhao ◽

Alan Wang ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Deep Learning ◽

Super Resolution ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri

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Fluid–structure interaction simulations outperform computational fluid dynamics in the description of thoracic aorta haemodynamics and in the differentiation of progressive dilation in Marfan syndrome patients

Royal Society Open Science ◽

10.1098/rsos.191752 ◽

2020 ◽

Vol 7 (2) ◽

pp. 191752

Author(s):

R. Pons ◽

A. Guala ◽

J. F. Rodríguez-Palomares ◽

J. C. Cajas ◽

L. Dux-Santoy ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Maximum Velocity ◽

Ascending Aorta ◽

4D Flow Mri ◽

4D Flow ◽

Cfd Simulations ◽

Structure Interaction ◽

Flow Displacement ◽

Flow Mri

Abnormal fluid dynamics at the ascending aorta may be at the origin of aortic aneurysms. This study was aimed at comparing the performance of computational fluid dynamics (CFD) and fluid–structure interaction (FSI) simulations against four-dimensional (4D) flow magnetic resonance imaging (MRI) data; and to assess the capacity of advanced fluid dynamics markers to stratify aneurysm progression risk. Eight Marfan syndrome (MFS) patients, four with stable and four with dilating aneurysms of the proximal aorta, and four healthy controls were studied. FSI and CFD simulations were performed with MRI-derived geometry, inlet velocity field and Young's modulus. Flow displacement, jet angle and maximum velocity evaluated from FSI and CFD simulations were compared to 4D flow MRI data. A dimensionless parameter, the shear stress ratio (SSR), was evaluated from FSI and CFD simulations and assessed as potential correlate of aneurysm progression. FSI simulations successfully matched MRI data regarding descending to ascending aorta flow rates ( R 2 = 0.92) and pulse wave velocity ( R 2 = 0.99). Compared to CFD, FSI simulations showed significantly lower percentage errors in ascending and descending aorta in flow displacement (−46% ascending, −41% descending), jet angle (−28% ascending, −50% descending) and maximum velocity (−37% ascending, −34% descending) with respect to 4D flow MRI. FSI- but not CFD-derived SSR differentiated between stable and dilating MFS patients. Fluid dynamic simulations of the thoracic aorta require fluid–solid interaction to properly reproduce complex haemodynamics. FSI- but not CFD-derived SSR could help stratifying MFS patients.

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