Comparison of Prospective and Retrospective Gated 4D Flow Cardiac MR Image Acquisitions in the Carotid Bifurcation

2021 ◽  
Author(s):  
Elliott R. Hurd ◽  
Mengjiao Han ◽  
Jason K. Mendes ◽  
J. Rock Hadley ◽  
Chris R. Johnson ◽  
...  
Keyword(s):  
Cardiac Mri ◽  
Carotid Bifurcation ◽  
Bulk Flow ◽  
External Carotid ◽  
Retrograde Flow ◽  
4D Flow ◽  
Velocity Magnitude ◽  
Prospective Gating ◽  
Flow Features ◽  
Temporal Coverage

Abstract The superior temporal coverage of retrospective versus prospective gating in 4D flow cardiac MRI (cMRI) imaging offers advantages in comprehensively evaluating the hemodynamic environment across the complete cardiac cycle; however, retrospective acquisitions may result in temporal smoothing. Thus, the purpose of this study was to evaluate the agreement of 4D flow cMRI-derived bulk flow features and fluid (blood) velocities in the carotid bifurcation using prospective and retrospective gating techniques. Prospective and retrospective ECG-gated three-dimensional (3D) cine phase-contrast cardiac MRI with three-direction velocity encoding (i.e., 4D flow cMRI) data were acquired in ten carotid bifurcations from men (n = 3) and women (n = 2) that were cardiovascular disease-free. Velocity magnitude data were extracted from the fluid domain within the image volumes and evaluated across the entire volume or at defined anatomic planes (common, internal, external carotid arteries). Vector magnitudes were decomposed into components to quantify flow direction and disturbances, including retrograde flow. Flow streamlines encoded for velocity magnitude and velocity profiles were generated. Qualitative and quantitative agreement was observed in bulk flow features and fluid velocity magnitudes derived from either prospective or retrospective ECG-gated 4D flow cMRI. No significant differences in velocity magnitudes or components (υr, υθ, υz) were observed. Importantly, retrospective acquisitions captured increased retrograde flow in the internal carotid artery (i.e., carotid sinus) compared to prospective acquisitions. Prospective and retrospective ECG-gated 4D flow cMRI acquisitions provide comparable evaluations of the hemodynamic environment in the carotid bifurcation. However, the increased temporal coverage of retrospective acquisitions depicts disturbed blood flow patterns not captured by the prospective gating technique.

On the Importance of Assumptions for Bulk Flow in Hemodynamic Models of the Carotid Bifurcation

2011 ◽  
Author(s):  
Umberto Morbiducci ◽  
Diana Massai ◽  
Diego Gallo ◽  
Raffaele Ponzini ◽  
Marco A. Deriu ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Carotid Bifurcation ◽  
Flow Fields ◽  
Transport Processes ◽  
Bulk Flow ◽  
Arterial System ◽  
Vortical Flow ◽  
Primary Role ◽  
4D Flow ◽  
The Impact

It is widely accepted that the local hemodynamics in the arterial system affects the atherogenic process. In particular the hemodynamic environment at the carotid artery bifurcation has been widely studied due to its predilection for atherosclerosis. Much effort has been spent in the past on image-based CFD carotid bifurcation models to assess the sensitivity to several assumptions of wall shear stress (WSS)-based parameters as indicators of abnormal flow. This luminal-surface-oriented approach was historically driven by histological observations on samples of the vessel wall. The consequence for this was that the reduction of the complexity of 4D flow fields focused mainly on WSS. However, few studies have provided adequate insights into the influence of these assumptions in order to confidently model the 4D hemodynamics within the bifurcation. Only recently the interest in the role played by the bulk flow in the development of the arterial disease has grown dramatically. This is the consequence of the emerging awareness that arterial hemodynamics, being an intricate process that involves interaction, reconnection and continuous re-organization of structures, could play a primary role in the regulation of mass transfer, and of its athero-protective/susceptible effect. Earlier works [1] pointed out the existence of a relationship between helical/vortical flow patterns and transport processes that could affect blood-vessel wall interaction, and might cause alterations in the residence time of atherogenic particles involved in the initiation of inflammatory response. Recently we introduced robust quantitative descriptors of bulk flow that can “reduce” the inherent complexity associated with 4D flow fields in arteries [1]. Here we present a study on the impact of assumptions on blood rheology and outflow boundary conditions (BCs) on bulk flow features within healthy carotid bifurcations, by using 4D flow descriptors. The final goal is to provide adequate insights not only to complement and to integrate, but also to extend with a quantitative characterization of the bulk flow the description currently adopted to classify altered hemodynamics.

scholarly journals Variations in the Branching Pattern of External Carotid Artery in South Kerala Population – A Cadaveric Study

2021 ◽  
Vol 8 (22) ◽  
pp. 1780-1785
Author(s):  
Manju Sudhakaran ◽  
Mini Alikunju ◽  
Vandana Latha Raveendran ◽  
Umesan Kannanvilakom Govindapillai
Keyword(s):  
Carotid Artery ◽  
Head And Neck ◽  
Carotid Arteries ◽  
Carotid Bifurcation ◽  
External Carotid Artery ◽  
External Carotid ◽  
Superior Thyroid Artery ◽  
South Indian Population ◽  
Branching Pattern ◽  
South Indian

BACKGROUND External carotid arteries account for a major share of arterial supply of head and neck regions. As variations are frequently observed in the branching pattern of external carotid artery, surgeons, radiologists and anaesthetists often encounter difficulties in various procedures of head and neck. The purpose of this study is to describe the variations in the branching pattern of external carotid artery as observed in South Indian population which definitely reduces its iatrogenic injuries associated with surgical and radiological procedures of head and neck. METHODS This is cross-sectional descriptive study. Bilateral neck dissection was done on twenty-two formalin fixed cadavers to study the branching pattern of external carotid artery during a period of two years in the Department of Anatomy in Government Medical College, Alappuzha. Common carotid, external carotid and internal carotid arteries were dissected. All the branches of external carotid artery were traced and the variations were noted. The distance between carotid bifurcation and point of origin of individual branches of external carotid were measured and statistically analyzed. RESULTS In the present study along with normal branching pattern of external carotid artery, variations like origin of superior thyroid artery from common carotid artery and also from carotid bifurcation were seen. A common linguofacial trunk and direct origin of superior laryngeal artery from external carotid artery were also observed. CONCLUSIONS Prior knowledge of the variations will be helpful to surgeons and anaesthetists while dealing with these vessels during procedures of head and neck regions. KEYWORDS External Carotid Artery, Carotid Bifurcation, Superior Thyroid Artery, Linguofacial Trunk

scholarly journals Exploring the Relationships Between Hemodynamic Stresses in the Carotid Arteries

2021 ◽  
Vol 7 ◽  
Author(s):  
Magnus Ziegler ◽  
Jesper Alfraeus ◽  
Elin Good ◽  
Jan Engvall ◽  
Ebo de Muinck ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Carotid Arteries ◽  
Carotid Bifurcation ◽  
Vessel Diameter ◽  
Atherosclerotic Plaques ◽  
Shear Stresses ◽  
Strongly Correlated ◽  
4D Flow ◽  
Bifurcation Angle

Background: Atherosclerosis manifests as a focal disease, often affecting areas with complex hemodynamics such as the carotid bifurcation. The magnitude and regularity of the hemodynamic shear stresses acting on the vessel wall are thought to generate risk patterns unique to each patient and play a role in the pathogenesis of atherosclerosis. The involvement of different expressions of shear stress in the pathogenesis of carotid atherosclerosis highlights the need to characterize and compare the differential impact of the various expressions of shear stress in the atherosclerotic carotid bifurcation. Therefore, the aim of this study is to characterize and compare hemodynamic wall shear stresses (WSS) in the carotid arteries of subjects with asymptomatic atherosclerotic plaques. Shear stresses were also compared against vessel diameter and bifurcation angle to examine the relationships with the geometry of the carotid bifurcation.Methods: 4D Flow MRI and contrast-enhanced MRA data were acquired for 245 subjects with atherosclerotic plaques of at least 2.7 mm in conjunction with the Swedish CArdioPulmonary bioImage Study (SCAPIS). Following automatic segmentation and geometric analysis, time-resolved WSS and near-wall turbulent kinetic energy (nwTKE) were derived from the 4D Flow data. Whole-cycle parameters including time-averaged WSS and nwTKE, and the oscillatory shear index (OSI) were calculated. Pairwise Spearman rank-correlation analyses were used to investigate relationships among the hemodynamic as well as geometric parameters.Results: One hundred and seventy nine subjects were successfully segmented using automated tools and subsequently geometric and hemodynamic analyses were performed. Temporally resolved WSS and nwTKE were strongly correlated, ρ = 0.64. Cycle-averaged WSS and nwTKE were moderately correlated, ρ = 0.57. Cycle-average nwTKE was weakly correlated to OSI (ρ = −0.273), revealing that nwTKE provides information about disturbed flow on the vessel wall that OSI does not. In this cohort, there was large inter-individual variation for both WSS and nwTKE. Both WSS and nwTKE varied most within the external carotid artery. WSS, nwTKE, and OSI were weakly correlated to vessel diameter and bifurcation angle.Conclusion: The turbulent and mean component of WSS were examined together in vivo for the first time, and a strong correlation was found between them. nwTKE presents the opportunity to quantify turbulent wall stresses in vivo and gain insight into the effects of disturbed flow on the vessel wall. Neither vessel diameter nor bifurcation angle were found to be strongly correlated to the turbulent or mean component of WSS in this cohort.

scholarly journals Intravascular Endothelin-1 does not trigger or increase susceptibility to Spreading Depolarizations

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Kazutaka Sugimoto ◽  
Andreia Morais ◽  
Homa Sadeghian ◽  
Tao Qin ◽  
David Y. Chung ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carotid Artery ◽  
Carotid Bifurcation ◽  
External Carotid Artery ◽  
External Carotid ◽  
Sprague Dawley ◽  
Vascular Events ◽  
Endothelin 1 ◽  
Pathological Conditions ◽  
Potent Vasoconstrictor

Abstract Objectives Spreading depolarizations (SD) likely manifest as aura in migraineurs. Triggers are unknown although vascular events have been implicated. Direct carotid puncture has been reported to trigger migraine with aura. The potent vasoconstrictor endothelin-1 (ET-1), which can be released from the endothelium under pathological conditions, may play a role. Here, we tested whether intracarotid ET-1 infusion triggers SD and whether systemic ET-1 infusion increases the susceptibility to SD. Methods Carotid infusions were performed in mice (C57BL/6, male) through a catheter placed at the carotid bifurcation via the external carotid artery. Intracarotid ET-1 (1.25 nmol/ml) was infused at various rates (2–16 μl/min) with or without heparin in the catheter and compared with vehicle infusion (PBS with 0.01% acetic acid) or sham-operated mice (n = 5). Systemic infusions ET-1 (1 nmol/kg, n = 7) or vehicle (n = 7) infusions were performed in rats (Sprague-Dawley, male) via the tail vein. Electrical SD threshold and KCl-induced SD frequency were measured after the infusion. Results Intracarotid infusion of saline (n = 19), vehicle (n = 7) or ET-1 (n = 12) all triggered SDs at various proportions (21%, 14% and 50%, respectively). These were often associated with severe hypoperfusion prior to SD onset. Heparinizing the infusion catheter completely prevented SD occurrence during the infusions (n = 8), implicating microembolization from carotid thrombi as the trigger. Sham-operated mice never developed SD. Systemic infusion of ET-1 did not affect the electrical SD threshold or KCl-induced SD frequency. Conclusion Intravascular ET-1 does not trigger or increase susceptibility to SD. Microembolization was the likely trigger for migraine auras in patients during carotid puncture.

In Vitro Comparison of Four Cerebral Protection Filters for Preventing Human Plaque Embolization during Carotid Interventions

2002 ◽  
Vol 9 (6) ◽  
pp. 793-802 ◽  
Author(s):  
Stefan Müller-Hülsbeck ◽  
Thomas Jahnke ◽  
Carsten Liess ◽  
Christoph Glass ◽  
Friedrich Paulsen ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Carotid Bifurcation ◽  
External Carotid Artery ◽  
Cerebral Protection ◽  
External Carotid ◽  
Carotid Angioplasty ◽  
Protection Device ◽  
Fluid Medium ◽  
Vitro Model

Purpose: To evaluate in an in vitro bench-top model the efficacy of 4 filtration devices designed for cerebral protection during carotid angioplasty. Methods: Embolization during carotid angioplasty was simulated with human plaque material (8 to 12 particles weighing 6.02 ± 0.10 mg) in an open flow model with the aortic arch and carotid bifurcation made from elastic silicone tubes and saline used as the fluid medium. The 500 to 1500-µm particles were injected into the internal carotid artery (ICA) in front of the test protection device, which was deployed 5 cm distal to the bifurcation. Particles getting past the protection device or flowing into the external carotid artery (ECA) were caught in 100-µm filters and weighed. Ten trials were made on each of 4 devices: Angioguard, FilterWire EX, TRAP, and NeuroShield. All were deployed according to the manufacturers' directions except the FilterWire, which was manually repositioned in all tests to eliminate a gap between the filter and the tube wall. Results: The lowest weight of missed particles in the effluent was obtained with the NeuroShield (0.05 ± 0.04 mg, 0.8% of injected particle weight) and FilterWire (0.08 ± 0.05 mg, 1.3%; p=0.254 compared to NeuroShield, p=0.006 versus TRAP). The weight of particles missed by the TRAP device (0.16 ± 0.06 mg, 2.6%; p<0.001 versus NeuroShield and Angioguard, p<0.05 compared to Filter Wire) was higher, and the largest amount of missed particles was observed with the Angioguard filter (0.27 ± 0.06 mg, 4.4%; p<0.001 compared to all). NeuroShield and FilterWire were significantly different (p<0.001) compared to Angioguard and TRAP in a pairwise analysis. No embolization into the ECA occurred. Conclusions: In vitro, none of the tested devices had the ability to completely prevent embolization into the ICA. Comparing current designs, the NeuroShield filter and the FilterWire EX captured the highest percentage of human particles in this in vitro model, probably due to their larger filter volume.

Targeted Particle Tracking in Computational Models of Human Carotid Bifurcations

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Ian Marshall
Keyword(s):  
Healthy Volunteer ◽  
Carotid Artery ◽  
Flow Region ◽  
Carotid Bifurcation ◽  
Flow Patterns ◽  
External Carotid ◽  
Complex Flow ◽  
Imaging Science ◽  
Carotid Bulb ◽  
Human Carotid

A significant and largely unsolved problem of computational fluid dynamics (CFD) simulation of flow in anatomically relevant geometries is that very few calculated pathlines pass through regions of complex flow. This in turn limits the ability of CFD-based simulations of imaging techniques (such as MRI) to correctly predict in vivo performance. In this work, I present two methods designed to overcome this filling problem, firstly, by releasing additional particles from areas of the flow inlet that lead directly to the complex flow region (“preferential seeding”) and, secondly, by tracking particles both “downstream” and “upstream” from seed points within the complex flow region itself. I use the human carotid bifurcation as an example of complex blood flow that is of great clinical interest. Both idealized and healthy volunteer geometries are investigated. With uniform seeding in the inlet plane (in the common carotid artery (CCA)) of an idealized bifurcation geometry, approximately half the particles passed through the internal carotid artery (ICA) and half through the external carotid artery. However, of those particles entering the ICA, only 16% passed directly through the carotid bulb region. Preferential seeding from selected regions of the CCA was able to increase this figure to 47%. In the second method, seeding of particles within the carotid bulb region itself led to a very high proportion (97%) of pathlines running from CCA to ICA. Seeding of particles in the bulb plane of three healthy volunteer carotid bifurcation geometries led to much better filling of the bulb regions than by particles seeded at the inlet alone. In all cases, visualization of the origin and behavior of recirculating particles led to useful insights into the complex flow patterns. Both seeding methods produced significant improvements in filling the carotid bulb region with particle tracks compared with uniform seeding at the inlet and led to an improved understanding of the complex flow patterns. The methods described may be combined and are generally applicable to CFD studies of fluid and gas flow and are, therefore, of relevance in hemodynamics, respiratory mechanics, and medical imaging science.

Quantifying Loss Mechanisms in Turbine Tip Shroud Cavity Flows

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Timothy R. Palmer ◽  
Choon S. Tan ◽  
Humberto Zuniga ◽  
David Little ◽  
Matthew Montgomery ◽  
...  
Keyword(s):  
Functional Dependence ◽  
Main Flow ◽  
Leakage Flow ◽  
Recirculating Flow ◽  
Velocity Magnitude ◽  
Toroidal Vortices ◽  
Flow Features ◽  
The Difference ◽  
Gap Height ◽  
Tip Shroud

Numerical calculations, steady as well as unsteady, of flow in a turbine stage with a tip shroud cavity elucidate that the loss-generating flow features consist of tip seal leakage jet, the interaction of cavity exit flow with main flow, the partially recirculating cavity inlet flow interaction with vane wakes, and injection of leakage flow into the shroud cavity. The first two flow features, namely, the tip seal leakage flow and mixing of cavity exit flow with main flow, dominate while the injection of leakage flow plays an indirect role in affecting the loss generation associated with cavity exit flow. The tip shroud cavity flow essentially consists of a system of toroidal vortices, the configuration of which is set by the cavity geometry and changes when subject to unsteady vane–rotor interaction. The role which the toroidal vortices play in setting the cavity inlet recirculating flow pattern and loss generation is delineated. It is suggested that there exists a link between the inlet cavity sizing and the toroidal vortical structure. The computed results appear to indicate that the main flow path approximately perceives the presence of the tip shroud cavity as a sink–source pair; as such a flow model based on this approximation is formulated. Loss variations with tip gap height and leakage flow injection are assessed. Results show that the expected loss due to mixing has a functional dependence on the square of the difference in their velocity magnitude and swirl. The tip seal leakage jet loss scales approximately linearly with the corrected mass flow rate per unit area over the range of tip gaps investigated.

Cervical paragangliomas: diagnosis, management and complications

2001 ◽  
Vol 115 (6) ◽  
pp. 467-474 ◽  
Author(s):  
M. Hossam Thabet ◽  
Hesham Kotob
Keyword(s):  
Carotid Artery ◽  
Superior Laryngeal Nerve ◽  
Carotid Bifurcation ◽  
Styloid Process ◽  
External Carotid Artery ◽  
External Carotid ◽  
Digastric Muscle ◽  
Vascular Injuries ◽  
Nerve Paralysis ◽  
Transcervical Approach

Sixteen patients were diagnosed as suffering from cervical paragangliomas. Eleven patients (68.75 per cent) had twelve carotid paragangliomas (CPs), and five patients (31.25 per cent) had six vagal paragangliomas (VP). One CP (8.33 per cent) originated from paraganglia around the common carotid artery (CCA). Three cases of multiple paragangliomas are presented (18.75 per cent). In 80 per cent (4/5) of VP patients there was widening of the carotid bifurcation similar to that seen with CP. This widening occurred whenever the VP was large enough to grown in between the external carotid artery and internal carotid artery (ECA and ICA). Large VPs may displace the vessels either anterolaterally or anteromedially. Knowledge of the direction of the carotid displacement is essential to avoid intra-operative vascular injuries. Colour flow doppler ultrasound (CFD-US) was found to be a good non-invasive method for diagnosis of vascular neck swellings. It enabled the diagnosis of CP with 100 per cent accuracy, but it was not sufficient for diagnosis of high VP. A transcervical approach, cutting the digastric muscle and the styloid process with the attached ligaments and muscles, was sufficient for excision of most VP. However, midline mandibulotomy might be necessary with high VP. Vascular injuries occurred in 12.5 per cent (2/16) of patients. Superior laryngeal nerve and hypoglossal nerve paralysis occurred, respectively, in (2/11) and (1/11) of patients with CP. Vagal paralysis occurred in all patients with VP. Cerebrovascular accident and post-operative death occurred in one patient (6.26 per cent).

scholarly journals Variations, relations and clinical significance of carotid arterial system in anterior neck: a cadaveric study

2019 ◽  
Vol 7 (4) ◽  
pp. 1127
Author(s):  
Anasuya Ghosh ◽  
Subhramoy Chaudhury ◽  
Atin Datta
Keyword(s):  
Carotid Artery ◽  
Carotid Arteries ◽  
Internal Carotid ◽  
Hypoglossal Nerve ◽  
Carotid Bifurcation ◽  
External Carotid Artery ◽  
Arterial System ◽  
External Carotid ◽  
The Common ◽  
Carotid Arterial

Background: The common carotid, internal and external carotid arteries and their branches serve as major source of blood supply in head-neck region of human and are often encountered during numerous surgical and clinical interventions of neck.Methods: We dissected and examined both sides of neck in 49 well embalmed cadavers (98 sides). We recorded the following anatomical parameters of carotid arterial system-level of bifurcation, the relation between internal and external carotid arteries, branching pattern of anterior branches of external carotid artery, tortuosity in carotid arterial system, and relation of hypoglossal nerve with the carotid arteries.Results: In 56.16 % cases, the common carotid arterial bifurcation took place at the upper border of thyroid cartilage though high bifurcation was quite common (43.88%). The external carotid artery was located antero-medial to internal carotid artery in most cases (93.87%). Abnormal tortuosity of carotid arterial system was detected in 2.04% cases only. In 86.73% cases, the hypoglossal nerve crossed the internal and external carotid artery superior to carotid bifurcation above the level of hyoid bone while in 1 case it crossed immediately inferior to carotid bifurcation. In branching pattern, following variations were observed- linguo-facial trunk in 15.3% cases, thyro-lingual trunk in 5.1% cases, origin of superior thyroid artery from common carotid in 10.02% cases and origin of superior thyroid from internal carotid in one case (1.02%).Conclusions: The carotid arterial system has complex and variable anatomy in neck and this information should be kept in mind to avoid unwanted damage during surgical procedures of neck.

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