Aortic Hemodynamics in Patients With and Without Repair of Aortic Coarctation

Frydrychowicz, Alex; Markl, Michael; Hirtler, Daniel; Harloff, Andreas; Schlensak, Christian; Geiger, Julia; Stiller, Brigitte; Arnold, Raoul

doi:10.1097/rli.0b013e3182034fc2

Cited by 102 publications

(71 citation statements)

References 36 publications

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“…In MFS, in vivo identification of such secondary flow patterns may help to identify patients at risk for the development of typical vascular complications. Similar to the findings in bicuspid aortic valve or aortic coarctation, the visualization of altered hemodynamics may facilitate the understanding of the pathomechanisms leading to aneurysm formation and onset of dissection (10,16).…”

mentioning

confidence: 77%

Aortic flow patterns in patients with Marfan syndrome assessed by flow‐sensitive four‐dimensional MRI

Geiger

Markl

Herzer

et al. 2011

Magnetic Resonance Imaging

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Purpose: To apply time-resolved three-dimensional (3D) phase contrast MRI with three-directional velocity encoding (flow-sensitive 4D MRI) for the characterization of flow pattern changes in patients with Marfan syndrome (MFS) compared with normal controls.Materials and Methods: Flow-sensitive 4D MRI of the thoracic aorta (temporal resolution $45 ms, spatial resolution $2.4 Â 2.1 Â 2.8 mm 3 ) was performed in 24 MFS patients and 10 volunteers. Aortic flow patterns were visualized by 3D particle traces and streamlines. Global (affecting the complete lumen) and local (parts of the vessel lumen) helix and vortex flow in the ascending aorta (AAo), aortic arch, and descending aorta (DAo) were graded in 3 categories (blinded reading, two observers): none ¼ 0, moderate ¼ 1, pronounced ¼ 2.Results: Flow grading revealed similar global helix and vortex flow in the AAo and arch for MFS patients and controls. Local helix flow in the AAo was significantly (P ¼ 0.011) increased in patients and was associated with aortic sinus dilatation. The incidence of global helix and vortex flow in the DAo was increased in patients (77% and 50% of subjects) compared with controls (none and 10%). Conclusion:The 4D flow analysis revealed marked differences of the aortic flow patterns between Marfan patients and controls: Local helix flow in the patients' AAo may be associated with the increased incidence of aortic root dilatation. The flow alterations in the proximal DAo could explain the occurrence of Type-B dissection originating from this site.

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confidence: 77%

Aortic flow patterns in patients with Marfan syndrome assessed by flow‐sensitive four‐dimensional MRI

Geiger

Markl

Herzer

et al. 2011

Magnetic Resonance Imaging

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“…48,57 Helical flow can be regarded as the rotational motion of blood oriented normal to the mainstream of blood flow during its passage of the artery. 29,101 In the helical flow, the streamlines in the lumen of arteries demonstrate the shape of helices and those on the cross sections of the arteries exhibit secondary rotations. The special geometry and the helical flow in the aorta are possibly a typical example of 'form follows function' in the circulation, which secures the human ascending aorta to be insusceptible to atherosclerotic plaque formation.…”

Section: Introductionmentioning

confidence: 99%

Physiological Significance of Helical Flow in the Arterial System and its Potential Clinical Applications

et al. 2014

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Helical flow in the human aorta is possibly a typical example of 'form follows function' in the vascular system. The helical blood flow may provide guaranties for the inner surface of the ascending aortic wall to get smooth and even washing by the blood so that atherosclerotic plaques can hardly form in the area of the ascending aorta. It has been documented that the phenomenon of helical flow of blood is not just localized in the ascending aorta, it also exists in several large arteries and veins as well. Preliminary studies demonstrated the widely existing helical flow might play positive physiological roles in facilitating blood flow transport, suppressing disturbed blood flow, preventing the accumulation of atherogenic low density lipoproteins on the luminal surfaces of arteries, enhancing oxygen transport from the blood to the arterial wall and reducing the adhesion of blood cells on the arterial surface. These roles of helical blood flow may lessen the burden of arteries and protect the arteries from the pathology of atherosclerosis, thrombosis, and intimal hyperplasia. The great development of time-resolved three-dimensional phase contrast MRI (flow-sensitive 4D-MRI) and the advent of dimensionless indices such as helical flow index proposed to characterize helical flow make clinic quantification of the helical flow in the human large arteries possible. Moreover, researchers probed into the possibility to apply the mechanism of helical flow to the design of vascular interventions to reduce thrombus formation and intimal hyperplasia caused by abnormal flow conditions.

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“…We added zero mean Gaussian noise to the velocity field in each direction (x, y, and z directions) with four different variances (2.5, 5, 7.5, and 10%) of the peak velocity, which was set to 1 m/s. Subsequently, we applied our method to estimate the vorticity vector field, which was then compared with the theoretical values obtained from the derivative value of Equation [13]. The equation for vorticity vector x can be written as…”

Section: Robustness and Convergence Analysismentioning

confidence: 99%

“…Studies based on 3D cine PC-MRI performed on phantom data have revealed that vortex and helical flow can induce vessel wall injury and vascular remodeling (7,(9)(10)(11). Additionally, other studies have demonstrated that standard surgical procedures induce local and global hemodynamic changes of the treated section, altering the secondary flow patterns, which could lead to the reappearance of the pathology and the need for re-intervention (12)(13)(14)(15)(16)(17)(18)(19).…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional quantification of vorticity and helicity from 3D cine PC‐MRI using finite‐element interpolations

Sotelo

Urbina

Valverde

et al. 2017

Magnetic Resonance in Med

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Purpose: We propose a 3D finite-element method for the quantification of vorticity and helicity density from 3D cine phase-contrast (PC) MRI. Methods: By using a 3D finite-element method, we seamlessly estimate velocity gradients in 3D. The robustness and convergence were analyzed using a combined Poiseuille and Lamb-Ossen equation. A computational fluid dynamics simulation was used to compared our method with others available in the literature. Additionally, we computed 3D maps for different 3D cine PC-MRI data sets: phantom without and with coarctation (18 healthy volunteers and 3 patients).Results: We found a good agreement between our method and both the analytical solution of the combined Poiseuille and Lamb-Ossen. The computational fluid dynamics results showed that our method outperforms current approaches to estimate vorticity and helicity values. In the in silico model, we observed that for a tetrahedral element of 2 mm of characteristic length, we underestimated the vorticity in less than 5% with respect to the analytical solution. In patients, we found higher values of helicity density in comparison to healthy volunteers, associated with vortices in the lumen of the vessels. Conclusions: We proposed a novel method that provides entire 3D vorticity and helicity density maps, avoiding the used of reformatted 2D planes from 3D cine PC-MRI. Magn Reson Med 79:541-553,

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Aortic Hemodynamics in Patients With and Without Repair of Aortic Coarctation

Cited by 102 publications

References 36 publications

Aortic flow patterns in patients with Marfan syndrome assessed by flow‐sensitive four‐dimensional MRI

Aortic flow patterns in patients with Marfan syndrome assessed by flow‐sensitive four‐dimensional MRI

Physiological Significance of Helical Flow in the Arterial System and its Potential Clinical Applications

Three‐dimensional quantification of vorticity and helicity from 3D cine PC‐MRI using finite‐element interpolations

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