A pilot study investigating the use of 4D flow MRI for the assessment of splanchnic flow in patients suspected of mesenteric ischaemia

AbstractThe most common cause of chronic mesenteric ischaemia is atherosclerosis which results in limitation of blood flow to the gastrointestinal tract. This pilot study aimed to evaluate 4D flow MRI as a potential tool for the analysis of blood flow changes post-prandial within the mesenteric vessels. The mesenteric vessels of twelve people were scanned; patients and healthy volunteers. A baseline MRI scan was performed after 6 h of fasting followed by a post-meal scan. Two 4D flow datasets were acquired, over the superior mesenteric artery (SMA) and the main portal venous vessels. Standard 2D time-resolved PC-MRI slices were also obtained across the aorta above the coeliac trunk, superior mesenteric vein, splenic vein and portal vein (PV). In the volunteer cohort there was a marked increase in blood flow post-meal within the PV (p = 0.028), not seen in the patient cohort (p = 0.116). Similarly, there were significant flow changes within the SMA of volunteers (p = 0.028) but not for the patient group (p = 0.116). Our pilot data has shown that there is a significant haemodynamic response to meal challenge in the PV and SMA in normal subjects compared to clinically apparent CMI patients. Therefore, the interrogation of mesenteric venous vessels exclusively is a feasible method to measure post-prandial flow changes in CMI patients.

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Blood flow characteristics in the ascending aorta after aortic valve replacement—a pilot study using 4D-flow MRI

International Journal of Cardiology ◽

10.1016/j.ijcard.2013.11.034 ◽

2014 ◽

Vol 170 (3) ◽

pp. 426-433 ◽

Cited By ~ 45

Author(s):

Florian von Knobelsdorff-Brenkenhoff ◽

Ralf F. Trauzeddel ◽

Alex J. Barker ◽

Henriette Gruettner ◽

Michael Markl ◽

...

Keyword(s):

Blood Flow ◽

Pilot Study ◽

Aortic Valve ◽

Aortic Valve Replacement ◽

Valve Replacement ◽

Flow Characteristics ◽

Ascending Aorta ◽

4D Flow Mri ◽

4D Flow ◽

Flow Mri

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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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Four-Dimensional Flow MRI of Abdominal Veins: A Systematic Review

Diagnostics ◽

10.3390/diagnostics11050767 ◽

2021 ◽

Vol 11 (5) ◽

pp. 767

Author(s):

Simon O. Haarbye ◽

Michael B. Nielsen ◽

Adam E. Hansen ◽

Carsten A. Lauridsen

Keyword(s):

Systematic Review ◽

Blood Flow ◽

Portal Hypertension ◽

Healthy Subjects ◽

Visual Quality ◽

Sampling Strategies ◽

4D Flow Mri ◽

4D Flow ◽

Dimensional Flow ◽

Flow Mri

The aim of this systematic review is to provide an overview of the use of Four-Dimensional Magnetic Resonance Imaging of vector blood flow (4D Flow MRI) in the abdominal veins. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in MEDLINE, Cochrane Library, EMBASE, and Web of Science. Quality assessment of the included studies was performed using the QUADAS-2 tool. The initial search yielded 781 studies and 21 studies were included. All studies successfully applied 4D Flow MRI in abdominal veins. Four-Dimensional Flow MRI was capable of discerning between healthy subjects and patients with cirrhosis and/or portal hypertension. The visual quality and inter-observer agreement of 4D Flow MRI were rated as excellent and good to excellent, respectively, and the studies utilized several different MRI data sampling strategies. By applying spiral sampling with compressed sensing to 4D Flow MRI, the blood flow of several abdominal veins could be imaged simultaneously in 18–25 s, without a significant loss of visual quality. Four-Dimensional Flow MRI might be a useful alternative to Doppler sonography for the diagnosis of cirrhosis and portal hypertension. Further clinical studies need to establish consensus regarding MRI sampling strategies in patients and healthy subjects.

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