Cross‐modality and in‐vivo validation of 4D flow MRI evaluation of uterine artery blood flow in human pregnancy

Background: Retrograde diastolic blood flow in the proximal descending aorta (DAo), which connects plaques ≥4 mm thickness with brain-supplying arteries, has previously been identified as a possible source of brain embolism. Currently, only 4D flow MRI is able to visualize and quantify potential retrograde embolization pathways in the DAo in-vivo. Hence, it was our aim to test if the extent of retrograde flow could be estimated by routine 2D transesophageal echocardiography (TEE). Methods: Forty-eight acute stroke patients were prospectively included and they underwent Doppler examinations of the transition zone between the aortic arch and the DAo using a 20 mm 2D sample volume in longitudinal section at 90-140° Doppler angle during routine TEE. Velocity-time-integrals (VTI) were studied for antegrade and retrograde velocities and the ratio (VTIratio) was calculated and correlated with the length of retrograde pathlines at that site, which were visualized using 4D flow MRI at 3-Tesla. A receiver operating characteristic (ROC) curve was used to evaluate a threshold value of VTIratio in differentiating large (≥3 cm) from small (<3 cm) retrograde flow extent. Results: At the TEE measurement site, the mean VTIratio was 0.53 ± 0.16 and the mean length of retrograde pathlines reaching back into the aortic arch was 3.1 ± 1.4 cm. VTIratio was an independent predictor of retrograde pathline length (r = 0.44; p = 0.002). ROC analysis identified a VTIratio threshold value of 0.6012 with a sensitivity of 0.5, a specificity of 0.92, and positive and negative predictive values of 0.84 and 0.68, respectively. Accordingly, 11 (22.91%) patients had a VTIratio cutoff value ≥0.6012 and corresponding retrograde pathline length ≥3 cm in 4D flow MRI. Conclusions: TEE allows predicting the length of retrograde pathlines. Hence, it may offer a cost-effective way to investigate independent predictors of DAo flow reversal in large-scale studies. However, TEE is only of limited value as a screening tool for high retrograde flow in a clinical setting, as only ∼23% of patients can be spared 4D flow MRI, which remains indispensable for the exact assessment of individual embolization pathways from plaques of the DAo in-vivo.

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Accuracy of blood flow assessment in cerebral arteries with 4D flow MRI: Evaluation with three segmentation methods

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.26641 ◽

2019 ◽

Vol 50 (2) ◽

pp. 511-518 ◽

Cited By ~ 9

Author(s):

Tora Dunås ◽

Madelene Holmgren ◽

Anders Wåhlin ◽

Jan Malm ◽

Anders Eklund

Keyword(s):

Blood Flow ◽

Cerebral Arteries ◽

4D Flow Mri ◽

4D Flow ◽

Segmentation Methods ◽

Flow Mri ◽

Mri Evaluation

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In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.23906 ◽

2012 ◽

Vol 37 (5) ◽

pp. 1100-1108 ◽

Cited By ~ 60

Author(s):

Alejandro Roldán-Alzate ◽

Alex Frydrychowicz ◽

Eric Niespodzany ◽

Ben R. Landgraf ◽

Kevin M. Johnson ◽

...

Keyword(s):

Portal Hypertension ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri ◽

In Vivo Validation

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Four-Dimensional Flow Magnetic Resonance Imaging and Applications in Cardiology

10.5772/intechopen.99362 ◽

2021 ◽

Author(s):

Patrick Geeraert ◽

Hansuk Kim ◽

Safia Ihsan Ali ◽

Ashifa Hudani ◽

Shirin Aliabadi ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Blood Flow ◽

Magnetic Resonance ◽

Resonance Imaging ◽

4D Flow Mri ◽

4D Flow ◽

Great Vessels ◽

Flow Mri ◽

Magnetic Resonance Imaging Mri

Blood flow through the heart and great vessels moves in three dimensions (3D) throughout time. However, the assessment of its 3D nature has been limited in the human body. Recent advances in magnetic resonance imaging (MRI) allow for the comprehensive visualization and quantification of in-vivo flow dynamics using four-dimensional (4D) flow MRI. In addition, this technique provides the opportunity to obtain advanced hemodynamic biomarkers such as vorticity, helicity, wall shear stress (WSS), pressure gradients, viscous energy loss (EL), and turbulent kinetic energy (TKE). This chapter will introduce 4D flow MRI which is currently used for blood flow visualization and advanced quantification of cardiac hemodynamic biomarkers. We will discuss its advantages relative to other in-vivo flow imaging techniques and describe its potential clinical applications in cardiology.

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In-vitro and In-Vivo Assessment of 4D Flow MRI Reynolds Stress Mapping for Pulsatile Blood Flow

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.774954 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hojin Ha ◽

Hyung Kyu Huh ◽

Kyung Jin Park ◽

Petter Dyverfeldt ◽

Tino Ebbers ◽

...

Keyword(s):

Blood Flow ◽

Reynolds Stress ◽

Normal Subjects ◽

Interventional Treatment ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri ◽

Turbulence Analysis

Imaging hemodynamics play an important role in the diagnosis of abnormal blood flow due to vascular and valvular diseases as well as in monitoring the recovery of normal blood flow after surgical or interventional treatment. Recently, characterization of turbulent blood flow using 4D flow magnetic resonance imaging (MRI) has been demonstrated by utilizing the changes in signal magnitude depending on intravoxel spin distribution. The imaging sequence was extended with a six-directional icosahedral (ICOSA6) flow-encoding to characterize all elements of the Reynolds stress tensor (RST) in turbulent blood flow. In the present study, we aimed to demonstrate the feasibility of full RST analysis using ICOSA6 4D flow MRI under physiological conditions. First, the turbulence analysis was performed through in vitro experiments with a physiological pulsatile flow condition. Second, a total of 12 normal subjects and one patient with severe aortic stenosis were analyzed using the same sequence. The in-vitro study showed that total turbulent kinetic energy (TKE) was less affected by the signal-to-noise ratio (SNR), however, maximum principal turbulence shear stress (MPTSS) and total turbulence production (TP) had a noise-induced bias. Smaller degree of the bias was observed for TP compared to MPTSS. In-vivo study showed that the subject-variability on turbulence quantification was relatively low for the consistent scan protocol. The in vivo demonstration of the stenosis patient showed that the turbulence analysis could clearly distinguish the difference in all turbulence parameters as they were at least an order of magnitude larger than those from the normal subjects.

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Associations between haemodynamics and wall enhancement of intracranial aneurysm

Stroke and Vascular Neurology ◽

10.1136/svn-2020-000636 ◽

2021 ◽

pp. svn-2020-000636

Author(s):

Miaoqi Zhang ◽

Fei Peng ◽

Xin Tong ◽

Xin Feng ◽

Yunduo Li ◽

...

Keyword(s):

Blood Flow ◽

High Resolution ◽

Ordinal Regression ◽

Parent Artery ◽

Black Blood ◽

4D Flow Mri ◽

4D Flow ◽

Unruptured Intracranial Aneurysms ◽

Black Blood Mri ◽

Flow Mri

Background and purposePrevious studies have reported about inflammation processes (IPs) that play important roles in aneurysm formation and rupture, which could be driven by blood flow. IPs can be identified using aneurysmal wall enhancement (AWE) on high-resolution black-blood MRI (BB-MRI) and blood flow haemodynamics can be demonstrated by four-dimensional-flow MRI (4D-flow MRI). Thus, this study investigated the associations between AWE and haemodynamics in unruptured intracranial aneurysms (IA) by combining 4D-flow MRI and high-resolution BB-MRI.Materials and methodsBetween April 2014 and October 2017, 48 patients with 49 unruptured IA who underwent both 4D-flow MRI and high-resolution BB-MRI were retrospectively included in this study. The haemodynamic parameters demonstrated using 4D-flow MRI were compared between different AWE patterns using the Kruskal-Wallis test and ordinal regression.ResultsThe results of Kruskal-Wallis test showed that the average wall shear stress in the IA (WSSavg-IA), maximum through-plane velocity in the adjacent parent artery, inflow jet patterns and the average vorticity in IA (vorticityavg-IA) were significantly associated with the AWE patterns. Ordinal regression analysis identified WSSavg-IA (p=0.002) and vorticityavg-IA (p=0.033) as independent predictors of AWE patterns.ConclusionA low WSS and low average vorticity were independently associated with a high AWE grade for IAs larger than 4 mm. Therefore, WSS and average vorticity could predict AWE and circumferential AWE.

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