Clinical Applications of 4D Flow MRI in the Portal Venous System

Oechtering, T; Roberts, Grant S.; Panagiotopoulos, Nikolaos; Wieben, Oliver; Reeder, Scott B.; Roldán‐Alzate, Alejandro

doi:10.2463/mrms.rev.2021-0105

Cited by 15 publications

(10 citation statements)

References 84 publications

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“…Finally, our pressure calculations assume Poiseuille flow and do not account for the non-Newtonian nature of blood, nor do they capture any minor resistive losses. Future simulations could incorporate more realistic scaling laws for resistance through microvasculature and perhaps utilize results of 3D direct numerical simulations and/or 4D magnetic resonance imaging (MRI) to improve blood flow modeling in the largest vessels (63, 64).…”

Section: Discussionmentioning

confidence: 99%

Lumped Parameter Liver Simulation to Predict Acute Hemodynamic Alterations Following Partial Resections

Tithof

Pruett

Rao

2022

Preprint

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Partial liver resections are routinely performed in living donor liver transplantation and to debulk tumors in liver malignancies. Due to the complexity of the interconnected hepatic vasculature, pre- and intra-operative decisions on vessel reconstruction for adequate inflow and outflow are challenging. Pre-operative evaluation of hepatic vasculature has predominantly been limited to radiological imaging and has failed to account for post-resection hepatic hemodynamic alterations. Substantial evidence suggests post-surgical increase in local volume flow rate enhances shear stress, signaling hepatic regeneration that is critical for hepatic volume restoration. However, excessive shear stress from extensive hepatic volume reduction has been postulated to result in small for size syndrome and liver failure. Predicting alterations in shear stress, flow velocity, and speed throughout the liver is particularly challenging due to the dendritic architecture of the portal and arterial vasculature that spans several orders of magnitude in diameter. Therefore, we developed a mathematical lumped parameter model implementing realistic heterogeneities in hepatic inflow/outflow of the human liver to simulate surgical resection alterations in perfusion across all hepatic segments. Our model is parameterized based on clinical measurements, relies on only a single free parameter, and accurately captures established blood perfusion characteristics. We quantify changes in volume flow rate, average blood flow velocity, and wall shear stress following variable, realistic liver resections and make comparisons to the intact liver. Our numerical model runs on a laptop in minutes and can be adapted to individualized patient-specific anatomy, providing a substantial advancement towards a novel computational tool for assisting pre- and intra-operative surgical decisions for liver resections.

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Section: Discussionmentioning

confidence: 99%

Lumped Parameter Liver Simulation to Predict Acute Hemodynamic Alterations Following Partial Resections

Tithof

Pruett

Rao

2022

Preprint

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“…[6][7][8][9][10][11] Such biomarkers are clinically validated in various investigations and used in many cardiovascular studies, as discussed in this special issue. [12][13][14][15][16][17] Current Limitations of 4D Flow MRI Although 4D Flow MRI has many advantages, some shortcomings need to be addressed. The current limitations and their potential solutions are as follows:…”

Section: Various Physiologically Relevant Indices Of Hemodynamics Can...mentioning

confidence: 99%

Why 4D Flow MRI? Real Advantages

2022

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This special issue of Magnetic Resonance in Medical Sciences features the most recent reviews on 4D Flow MRI. These reviews deal with the current status of the emerging technique of 4D Flow MRI facilitated in various areas that are difficult to obtain with conventional flowmetry. MR signals inherently contain flow velocity information. In previous decades, in vivo blood flow measurement was traditionally performed by 2D methods, such as Doppler ultrasonography and 2D phase-contrast MRI, which have long been regarded as mature techniques in hemodynamic flowmetry. Although 2D velocimetries have many advantages over 4D Flow MRI in terms of cost and accessibility, and provide excellent temporal and in-plane spatial resolutions, they also have some disadvantages. The emerging technology of 4D Flow MRI can overcome the shortcomings of conventional 2D imaging. In recent years, hemodynamic analysis has witnessed significant progress that is primarily attributable to advances in 4D Flow MRI.

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“…Sex (male, female) 12,13,[27][28][29] The 4D flow MRI technique offers a wide scan range to cover portosystemic shunt, 18 but requires a long scan time to obtain flow data and anatomical data. 30 CT has significant advantages over MRI in terms of short scan time and providing planning data for operative procedures, understanding of the complicated anatomy of the portosystemic shunt, determining statistics regarding catheterization, and deciding which vein among multiple portosystemic shunts should be embolized before IR treatment. 19 Radiation exposure is one of the drawbacks of 4DCT.…”

Section: Reversed Flow (N = 17) Pmentioning

confidence: 99%

Identification of reversed portal flow on 4DCT and of factors contributing to reversed portal flow in patients with liver cirrhosis and portosystemic shunt before interventional radiology procedures

Kageyama¹,

Yamamoto²,

Jogo³

et al. 2022

Hepatology Research

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Aim Patients with liver cirrhosis and portosystemic shunt occasionally develop reversed portal flow in the portal venous system. The factors contributing to reversed portal flow in these patients remain unclear. The aim of this study was to identify factors contributing to reversed portal flow in patients with portosystemic shunts based on four‐dimensional computed tomography (4DCT), which visualized flow dynamics in the portal venous system. Methods Data from 34 consecutive patients with portosystemic shunts who had undergone 4DCT before interventional radiology procedures were retrospectively investigated in this study. Uni‐ and multivariate analyses were performed to identify factors contributing to reversed portal flow. Results Flow dynamics could be visualized on 4DCT in 32 of the 34 patients. Fifteen patients had forward portal flow; 17 had reversed portal flow. The main portal, splenic, and superior mesenteric veins displayed reversed portal flow in five, 12, and five vessels, respectively. Portosystemic shunt originating from splenic and superior mesenteric veins, worse albumin‐bilirubin score, and small main portal vein diameter were significant factors contributing to reversed portal flow in both univariate (p = 0.049, p = 0.027, and p = 0.002) and multivariate (odds ratio [OR] 6.345, p = 0.012; OR 4.279, p = 0.039; and OR 5.516, p = 0.019) analyses. Conclusions The reversed portal flow was visualized on 4DCT. Portosystemic shunt originating distant to the liver, worse albumin‐bilirubin score, and small diameter of the main portal vein were factors contributing to reversed flow in the portal venous system.

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Clinical Applications of 4D Flow MRI in the Portal Venous System

Cited by 15 publications

References 84 publications

Lumped Parameter Liver Simulation to Predict Acute Hemodynamic Alterations Following Partial Resections

Lumped Parameter Liver Simulation to Predict Acute Hemodynamic Alterations Following Partial Resections

Why 4D Flow MRI? Real Advantages

Identification of reversed portal flow on 4DCT and of factors contributing to reversed portal flow in patients with liver cirrhosis and portosystemic shunt before interventional radiology procedures

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