Three‐dimensional hemodynamics in intracranial aneurysms: influence of size and morphology

Schnell, Susanne; Ansari, Sameer A.; Vakil, Parmede; Wasielewski, Marie; Carr, Maria; Hurley, Michael C.; Bendok, Bernard R.; Batjer, H. Hunt; Carroll, Timothy J.; Carr, James C.; Markl, Michael

doi:10.1002/jmri.24110

Cited by 78 publications

(78 citation statements)

References 49 publications

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“…[37][38][39] Moreover, previous studies confirmed the feasibility of depicting the aneurysmal inflow. 18,20,23,26,27 Consequently, 4D flow MR imaging is the criterion standard for the identification of the inflow zone of cerebral aneurysms. According to others, 11,13,40 the inflow zone of lateral-projection aneurysms was located on the distal neck.…”

Section: Discussionmentioning

confidence: 99%

“…More recently, 4D flow MR imaging based on time-resolved 3D cine phase-contrast MR imaging techniques was used to evaluate the hemodynamics of cerebral aneurysms. [18][19][20][21][22][23][24][25][26][27] However, 4D flow MR imaging requires additional time for data acquisition, and TC 3D MRA may be a convenient alternative to 4D flow MR imaging for identifying the aneurysmal inflow zone.…”

Section: -15mentioning

confidence: 99%

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Identification of the Inflow Zone of Unruptured Cerebral Aneurysms: Comparison of 4D Flow MRI and 3D TOF MRA Data

Futami

Sano

Misaki

et al. 2014

AJNR Am J Neuroradiol

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Section: Discussionmentioning

confidence: 99%

Section: -15mentioning

confidence: 99%

Identification of the Inflow Zone of Unruptured Cerebral Aneurysms: Comparison of 4D Flow MRI and 3D TOF MRA Data

Futami

Sano

Misaki

et al. 2014

AJNR Am J Neuroradiol

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“…Aneurysms are pathologic dilations of the vessel wall, and their flow characteristics have been extensively investigated as mechanically and biologically related with the initiation, growth, and eventual rupture of aneurysms (Cebral et al 2011;Geers et al 2011;Schnell et al 2014;Gopalakrishnan et al 2014;Arzani et al 2016).…”

Section: Cerebral Arteries With Aneurysmsmentioning

confidence: 99%

Flow complexity in open systems: interlacing complexity index based on mutual information

et al. 2017

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Flow complexity is related to a number of phenomena in science and engineering, which has been approached from the perspective of chaotic dynamical systems, ergodic processes, or mixing of fluids, just to name a few. To the best of our knowledge, all existing methods to quantify flow complexity are only valid for infinite time evolutions, for closed systems or for mixing of two substances. We introduce an index of flow complexity coined interlacing complexity index (ICI), valid for a single phase flow in an open system with inlet and outlet regions, involving finite times. ICI is based on Shannon's mutual information (MI), and inspired by an analogy between inlet-outlet open flow systems and communication systems in communication theory. The roles of transmitter, receiver, and communication channel are played, respectively, by the inlet, the outlet, and the flow transport between them. A perfectly laminar flow in a straight tube can be compared to an ideal communication channel where the transmitted and received messages are identical and hence the MI between input and output is maximal. For more complex flows, generated by more intricate conditions or geometries, the ability to discriminate the outlet position by knowing the inlet position is decreased, reducing the corresponding MI. The behaviour of the ICI has been tested with numerical experiments on diverse flows cases. The results indicate that the ICI provides a sensitive complexity measure with intuitive interpretation in a diversity of conditions and in agreement with other observations, such as Dean vortices and subjective visual assessments. As a crucial component of the ICI formulation, we also introduce the natural distribution of streamlines and the natural distribution of world-lines, with invariance properties with respect to the cross section used to parameterize them, valid for any type of mass-preserving flow.

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“…The increasing number of studies applying the MRI-based WSS estimation in-vivo [23,[34][35][36][37][38][39][40][41][42][43] prompt detailed investigations of the accuracy of MRI-based WSS estimation. Estimates of WSS from 4D flow data in an intracranial aneurysms showed large discrepancies compared to subject-specific CFD simulations [36].…”

Section: Mri-based Wall Shear Stress Estimationmentioning

confidence: 99%

“…The use of 4D flow MRI has increased the understanding of normal and abnormal blood flow and has proven valuable in various clinical applications [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Ample evidence indicates that WSS is involved in the pathogenesis of atherosclerosis and aneurysms [28][29][30][31][32][33], and an increasing number of studies apply MRI-based WSS estimation invivo [23,[34][35][36][37][38][39][40][41][42][43]. However, many cardiovascular applications of 4D flow MRI require large volumetric coverage resulting in scan times of about 20-40 minutes, which may be prohibitive in many cases.…”

Section: Introductionmentioning

confidence: 99%

Fast and Accurate 4D Flow MRI for Cardiovascular Blood Flow Assessment

Petersson¹

2013

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The study of blood flow is essential in understanding the physiology and pathophysiology of the cardiovascular system. Small disturbances of the blood flow may over time evolve and contribute to cardiovascular pathology. While the blood flow in a healthy human appears to be predominately laminar, turbulent or transitional blood flow is thought to be involved in the pathogenesis of several cardiovascular diseases. Wall shear stress is the frictional force of blood on the vessel wall and has been linked to the pathogenesis of atherosclerosis and aneurysms. Despite the importance of hemodynamic factors, cardiovascular diagnostics largely relies on the indirect estimation of function based on morphological data.Time-resolved three-dimensional (3D) phase-contrast magnetic resonance imaging (MRI), often referred to as 4D flow MRI, is a versatile and non-invasive tool for cardiovascular blood flow assessment. The use of 4D flow MRI permits estimation of flow volumes, pressure losses, wall shear stress, turbulence intensity and many other unique hemodynamic parameters. However, 4D flow MRI suffers from long scan times, sometimes over 40 minutes. Furthermore, the accuracy of the many different 4D flow MRI-based applications and estimates have not been thoroughly examined.In this thesis, the accuracy of 4D flow MRI-based turbulence intensity mapping and wall shear stress estimation was investigated by using numerical simulations of MRI flow measurements. While the results from the turbulence intensity mapping agreed well with reference values from computational fluid dynamics data, the accuracy of the MRI-based wall shear stress estimates was found to be very sensitive to different parameters, especially to spatial resolution, and wall shear stress values over 5 N/m 2 were not well resolved.To reduce the scan time, a 4D flow MRI sequence using spiral k-space trajectories was implemented and validated in-vivo and in-vitro. The scan time of 4D flow MRI was reduced by more than two-fold compared to a conventional Cartesian acquisition already accelerated using SENSE factor 2, and the data quality was maintained. For a 4D flow scan of the human heart, the use of spiral k-space trajectories resulted in a scan time of around 13 min, compared to 30 min for the Cartesian acquisition. By combining parallel imaging and spiral trajectories, the total scan time of a 4D flow measurement of the entire heart may be further reduced. This scan time reduction may also be traded for higher spatial resolution.Numerical simulation of 4D flow MRI may act as an important tool for future optimization and validation of the spiral 4D flow sequence. The scan-time reductions offered by the spiral k-space trajectories can help to cut costs, save time, reduce discomfort for the patient as well as to decrease the risk for motion artifacts. These benefits may facilitate an expanded clinical and investigative use of 4D flow MRI, including larger patient research studies.v Populärvetenskaplig sammanfattningHjärt-och kärlsjukdom är fortfarande den ...

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Three‐dimensional hemodynamics in intracranial aneurysms: influence of size and morphology

Cited by 78 publications

References 49 publications

Identification of the Inflow Zone of Unruptured Cerebral Aneurysms: Comparison of 4D Flow MRI and 3D TOF MRA Data

Identification of the Inflow Zone of Unruptured Cerebral Aneurysms: Comparison of 4D Flow MRI and 3D TOF MRA Data

Flow complexity in open systems: interlacing complexity index based on mutual information

Fast and Accurate 4D Flow MRI for Cardiovascular Blood Flow Assessment

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