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Blood Flow Velocity Pulsatility and Arterial diameter Pulsatility Measurements of the Intracranial Arteries Using 4d pc-mri

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NEUROINFORMATICS 2022年第2期20卷 317-326页

作者： van Hespen, Kees M. Kuijf, Hugo J. Hendrikse, Jeroen Luijten, Peter R. Zwanenburg, Jaco J. M. UMC Utrecht Ctr Image Sci Utrecht Netherlands UMC Utrecht Image Sci Inst Utrecht Netherlands UMC Utrecht Dept Radiol Utrecht Netherlands

4d phase contrast magnetic resonance imaging (pc-mri) allows for the visualization and quantification of the cerebral blood flow. A drawback of software that is used to quantify the cerebral blood flow is that it oftentimes assumes a static arterial luminal area over the cardiac cycle. Quantifying the lumen area pulsatility index (aPI), i.e. the change in lumen area due to an increase in distending pressure over the cardiac cycle, can provide insight in the stiffness of the arteries. Arterial stiffness has received increased attention as a predictor in the development of cerebrovascular disease. In this study, we introduce software that allows for measurement of the aPI as well as the blood flow velocity pulsatility index (vPI) from 4d pc-mri. The internal carotid arteries of seven volunteers were imaged using 7 T mri. The aPI and vPI measurements from 4d pc-mri were validated against measurements from 2d pc-mri at two levels of the internal carotid arteries (C3 and C7). The aPI and vPI computed from 4d pc-mri were comparable to those measured from 2d pc-mri (aPI: mean difference: 0.03 (limits of agreement: -0.14 - 0.23);vPI: 0.03 (-0.17-0.23)). The measured blood flow rate for the C3 and C7 segments was similar, indicating that our proposed software correctly captures the variation in arterial lumen area and blood flow velocity that exists along the distal end of the carotid artery. Our software may potentially aid in identifying changes in arterial stiffness of the intracranial arteries caused by pathological changes to the vessel wall.

关键词： 4d pc-mri Blood flow velocity pulsatility Arterial distensibility Intracranial arteries Arterial stiffness diameter pulsatility

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Bloodline: A system for the guided analysis of cardiac 4d pc-mri data

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COMPUTERS & GRAPHICS-UK 2019年 82卷 32-43页

作者： Koehler, Benjamin Grothoff, Matthias Gutberlet, Matthias Preim, Bernhard Magdeburg Univ Dept Simulat & Graph D-39106 Magdeburg Saxony Anhalt Germany Heart Ctr Leipzig Dept Diagnost & Intervent Radiol Leipzig Germany

4d pc-mri enables the assessment of blood flow velocity vectors of one heart beat. These time dependent, three-dimensional data allow for a comprehensive analysis and contain plenty of information. So far, 4d pc-mri is used for research purposes. One reason is a lack of standardized, easy-to-use evaluation software, which is crucial for potential application in clinical routine. In this system's paper, we present our software Bloodline, a tool combining advanced visual exploration and analysis of 4d pc-mri data. We will put emphasis on design decisions and requirements that arose from the close collaboration with cardiologists and radiologists. The tool provides a guided data processing and evaluation workflow. The pre-processing pipeline comprises generic data import, artifact correction, vessel segmentation, surface as well as centerline extraction, cardiac cycle definition, and landmark specification. Bloodline integrates advanced visualization techniques and facilitates a dataset evaluation within ten minutes. Qualitative and quantitative flow analysis methods are provided. The focus lies on the detection and characterization of vortices, which are correlated to cardiovascular diseases. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： 4d pc-mri Cardiac blood flow Flow visualization Flow quantification Heart

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A Survey of Cardiac 4d pc-mri data Processing

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COMPUTER GRAPHICS FORUM 2017年第6期36卷 5-35页

作者： Koehler, Benjamin Born, Silvia van Pelt, Roy F. P. Hennemuth, Anja Preim, Uta Preim, Bernhard Otto von Guericke Univ Dept Simulat & Graph Magdeburg Germany Univ Zurich Div Surg Res Zurich Switzerland Philips Healthcare Dept Image Guided Therapy Syst Best Netherlands Yacht Eindhoven Netherlands Fraunhofer MeVis Cardiovasc Res & Dev Bremen Germany Municipal Hosp Dept Diagnost Radiol Magdeburg Germany

Cardiac four-dimensional phase-contrast magnetic resonance imaging (4d pc-mri) acquisitions have gained increasing clinical interest in recent years. They allow to non-invasively obtain extensive information about patient-specific hemodynamics, and thus have a great potential to improve the diagnosis, prognosis and therapy planning of cardiovascular diseases. A dataset contains time-resolved, three-dimensional blood flow directions and strengths, making comprehensive qualitative and quantitative data analysis possible. Quantitative measures, such as stroke volumes, help to assess the cardiac function and to monitor disease progression. Qualitative analysis allows to investigate abnormal flow characteristics, such as vortices, which are correlated to different pathologies. Processing the data comprises complex image processing methods, as well as flow analysis and visualization. In this work, we mainly focus on the aorta. We provide an overview of data measurement and pre-processing, as well as current visualization and quantification methods. This allows other researchers to quickly catch up with the topic and take on new challenges to further investigate the potential of 4d pc-mri data.

关键词： 4d pc-mri data processing cardiovascular diseases aorta survey

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Motion-aware stroke volume quantification in 4d pc-mri data of the human aorta

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INTERNATIONAL JOURNAL OF COMPUTER ASSISTEd RAdIOLOGY ANd SURGERY 2016年第2期11卷 169-179页

作者： Koehler, Benjamin Preim, Uta Grothoff, Matthias Gutberlet, Matthias Fischbach, Katharina Preim, Bernhard Univ Magdeburg Dept Simulat & Graph D-39106 Magdeburg Germany Municipal Hosp Dept Diagnost Radiol Magdeburg Germany Ctr Heart Dept Diagnost & Intervent Radiol Leipzig Germany Univ Hosp Dept Radiol & Nucl Med Magdeburg Germany

4d pc-mri enables the noninvasive measurement of time-resolved, three-dimensional blood flow data that allow quantification of the hemodynamics. Stroke volumes are essential to assess the cardiac function and evolution of different cardiovascular diseases. The calculation depends on the wall position and vessel orientation, which both change during the cardiac cycle due to the heart muscle contraction and the pumped blood. However, current systems for the quantitative 4d pc-mri data analysis neglect the dynamic character and instead employ a static 3d vessel approximation. We quantify differences between stroke volumes in the aorta obtained with and without consideration of its dynamics. We describe a method that uses the approximating 3d segmentation to automatically initialize segmentation algorithms that require regions inside and outside the vessel for each temporal position. This enables the use of graph cuts to obtain 4d segmentations, extract vessel surfaces including centerlines for each temporal position and derive motion information. The stroke volume quantification is compared using measuring planes in static (3d) vessels, planes with fixed angulation inside dynamic vessels (this corresponds to the common 2d pc-mri) and moving planes inside dynamic vessels. Seven datasets with different pathologies such as aneurysms and coarctations were evaluated in close collaboration with radiologists. Compared to the experts' manual stroke volume estimations, motion-aware quantification performs, on average, 1.57 % better than calculations without motion consideration. The mean difference between stroke volumes obtained with the different methods is 7.82 %. Automatically obtained 4d segmentations overlap by 85.75 % with manually generated ones. Incorporating motion information in the stroke volume quantification yields slight but not statistically significant improvements. The presented method is feasible for the clinical routine, since computation times are low and e

关键词： 4d pc-mri CMR Stroke volume Motion Quantification 4d segmentation Graph cut

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Robust Cardiac Function Assessment in 4d pc-mri data of the Aorta and Pulmonary Artery

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COMPUTER GRAPHICS FORUM 2016年第1期35卷 32-43页

Four-dimensional phase-contrast magnetic resonance imaging (4d pc-mri) allows the non-invasive acquisition of time-resolved, 3d blood flow information. Stroke volumes (SVs) and regurgitation fractions (RFs) are two of the main measures to assess the cardiac function and severity of valvular pathologies. The flow rates in forward and backward direction through a plane above the aortic or pulmonary valve are required for their quantification. Unfortunately, the calculations are highly sensitive towards the plane's angulation since orthogonally passing flow is considered. This often leads to physiologically implausible results. In this work, a robust quantification method is introduced to overcome this problem. Collaborating radiologists and cardiologists were carefully observed while estimating SVs and RFs in various healthy volunteer and patient 4d pc-mri data sets with conventional quantification methods, that is, using a single plane above the valve that is freely movable along the centerline. By default it is aligned perpendicular to the vessel's centerline, but free angulation (rotation) is possible. This facilitated the automation of their approach which, in turn, allows to derive statistical information about the plane angulation sensitivity. Moreover, the experts expect a continuous decrease of the blood flow volume along the vessel course. Conventional methods are often unable to produce this behaviour. Thus, we present a procedure to fit a monotonous function that ensures such physiologically plausible results. In addition, this technique was adapted for the usage in branching vessels such as the pulmonary artery. The performed informal evaluation shows the capability of our method to support diagnosis;a parameter evaluation confirms the robustness. Vortex flow was identified as one of the main causes for quantification uncertainties.

关键词： scientific visualization 4d pc-mri stroke volume quantification I 4 9 [Computing Methodologies]: Image Processing and Computer Vision Applications

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does the Internal Carotid Artery Attenuate Blood-Flow Pulsatility in Small Vessel disease? A 7 T 4d-Flow mri Study

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JOURNAL OF MAGNETIC RESONANCE IMAGING 2022年第2期56卷 527-535页

作者： Tuijl, Rick J. Ruigrok, Ynte M. Geurts, Lennart J. Schaaf, Irene C. Biessels, Geert Jan Rinkel, Gabriel J. E. Velthuis, Birgitta K. Zwanenburg, Jaco J. M. Univ Utrecht Univ Med Ctr Utrecht Dept Radiol Brain Ctr Utrecht Netherlands Univ Utrecht Univ Med Ctr Utrecht Dept Neurol & Neurosurg Brain Ctr Utrecht Netherlands

Background Increased cerebral blood-flow pulsatility is associated with cerebral small vessel disease (cSVd). Reduced pulsatility attenuation over the internal carotid artery (ICA) could be a contributing factor to the development of cSVd and could be associated with intracranial ICA calcification (iICAC). Purpose To compare pulsatility, pulsatility attenuation, and distensibility along the ICA between patients with cSVd and controls and to assess the association between iICAC and pulsatility and distensibility. Study Type Retrospective, explorative cross-sectional study. Subjects A total of 17 patients with cSVd, manifested as lacunar infarcts or deep intracerebral hemorrhage, and 17 age- and sex-matched controls. Field Strength/Sequence Three-dimensional (3d) T1-weighted gradient echo imaging and 4d phase-contrast (pc) mri with a 3d time-resolved velocity encoded gradient echo sequence at 7 T. Assessment Blood-flow velocity pulsatility index (vPI) and arterial distensibility were calculated for seven ICA segments (C1-C7). iICAC presence and volume were determined from available brain CT scans (acquired as part of standard clinical care) in patients with cSVd. Statistical Tests Independent t-tests and linear mixed models. The threshold for statistically significance was P < 0.05 (two tailed). Results The cSVd group showed significantly higher ICA vPI and significantly lower distensibility compared to controls. Controls showed significant attenuation of vPI over the carotid siphon (-4.9% +/- 3.6%). In contrast, patients with cSVd showed no attenuation, but a significant increase of vPI (+6.5% +/- 3.1%). iICAC presence and volume correlated positively with vPI (r = 0.578) in patients with cSVd and negatively with distensibility (r = -0.386). Conclusion decreased distensibility and reduced pulsatility attenuation are associated with increased iICAC and may contribute to cSVd. Confirmation in a larger prospective study is required. Evidence Level 2 Technical Efficacy S

关键词： cerebral small vessel disease flow imaging pulsatility ultra-high field mri 4d pc-mri

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In vitro experiments on ICOSA6 4d flow mri measurement for the quantification of velocity and turbulence parameters

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MAGNETIC RESONANCE IMAGING 2020年 72卷 49-60页

作者： Ha, Hojin Park, Kyung Jin dyverfeldt, Petter Ebbers, Tino Yang, dong Hyun Kangwon Natl Univ Dept Mech & Biomed Engn Chunchon South Korea Yonsei Univ Dept Elect & Elect Engn Seoul South Korea Univ Ulsan Asan Med Ctr Dept Radiol Coll Med Seoul South Korea Linkoping Univ Dept Hlth Med & Caring Sci Linkoping Sweden Linkoping Univ Ctr Med Image Sci & Visualizat CMIV Linkoping Sweden

Purpose: To perform comprehensive in vitro experiments using six-directional icosahedral flow encoding (ICOSA6) 4d flow magnetic resonance imaging (mri) under various scan conditions to analyze the robustness of velocity and turbulence quantification. Materials and methods: In vitro flow phantoms with steady flow rates of 10 and 20 L/min were scanned using both conventional 4d flow mri and ICOSA6. Experiments focused on comparisons between ICOSA6 and conventional four point (4P) methods, and the effects of contrast agents, velocity encoding range (Venc), and scan direction on velocity and turbulence quantification. Results: The results demonstrated that 1) ICOSA6 improves the velocity-to-noise ratio (VNR) of velocity estimation by 33% (on average) and results in similar turbulent kinetic energy (TKE) estimation as the 4P method. 2) Measurements with a contrast agent resulted in more than a 2.5 fold increase in average VNR. However, the improvement of total TKE quantification was not obvious. 3) TKE estimation was less affected by Venc and the scan direction, whereas turbulence production (TP) estimation was largely affected by these measurement conditions. The effects of Venc and scan direction accounted for less than 11.63% of TKE estimation, but up to 33.89% of TP estimation. Conclusion: The ICOSA6 scheme is compatible with conventional 4d flow mri for velocity and TKE measurement. Contrast agents are effective at increasing VNR, but not signal-to-noise ratio for TKE quantification. The effects of Venc and scan direction influence total TP more than total TKE.

关键词： Turbulence Turbulence kinetic energy Reynolds stress Phase contrast mri 4d pc-mri 4d flow mri

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Relationship between diameter asymmetry of the anterior cerebral arteries of the Circle of Willis and asymmetry in diameters and blood flow of the upstream vasculature: preliminary results

Relationship between diameter asymmetry of the anterior cere...

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Conference on Medical Imaging - Biomedical Applications in Molecular, Structural, and Functional Imaging

作者： van Tuijl, Rick J. Vos, Iris N. Ruigrok, Ynte M. van der Schaaf, Irene C. Velthuis, Birgitta K. Zwanenburg, Jaco J. M. Univ Utrecht Univ Med Ctr Utrecht UMC Utrecht Brain Ctr Dept Radiol Utrecht Netherlands Univ Utrecht Univ Med Ctr Utrecht UMC Utrecht Brain Ctr Dept Neurol & Neurosurg Utrecht Netherlands

ISBN: (数字)9781510649484

ISBN: (纸本)9781510649484;9781510649477

Both internal carotid arteries (ICA) distribute blood via the anterior (ACA) and middle (MCA) cerebral arteries to the anterior part of the brain. Asymmetry of the pre-communicating part (A1-segment) of the ACA is common and is related to intracranial aneurysm formation. It is unknown if A1 asymmetry is also related to blood flow changes in the dominant A1 segment and the ipsilateral ICA and MCA. This study aims to relate artery diameters of both ICAs, M1-segments MCA and A1-segments ACA to blood-flow distribution in 10 subjects with symmetric A1s versus 10 with asymmetric A1s. diameter measurements of the ICA (C3 and C7 segments), M1 and A1-segments were performed manually on the time-of flight magnetic resonance angiography (TOF-MRA) using an in-house developed tool. 4d phase-contrast MR imaging (pc-mri)datasets were analyzed using CAAS software. The asymmetric group had on average 43% (range 26-84) asymmetry of the A1-segments and this asymmetry was directly related to the right-left flow difference (R-2=0.890). The asymmetric group also had increased diameters and blood-flow for all ICA, M1 and A1 segments on the dominant A1 side. In conclusion, this preliminary study showed that asymmetry in A1 diameter is directly associated with increased blood-flow in the ICA, MCA and ACA on the dominant side. Our findings should be confirmed in a larger population which will also help to find an ideal cut-off in asymmetry diameter measurement that reflects a statistically significant difference in blood flow and velocity.

关键词： A1-asymmetry Circle of Willis Blood flow 4d pc-mri

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Validation of pressure drop assessment using 4d flow mri-based turbulence production in various shapes of aortic stenoses

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MAGNETIC RESONANCE IN MEdICINE 2019年第2期81卷 893-906页

作者： Ha, Hojin Kvitting, John-Peder Escobar dyverfeldt, Petter Ebbers, Tino Kangwon Natl Univ Dept Mech & Biomed Engn Chunchon Kangwon Do South Korea Linkoping Univ Div Cardiovasc Med Dept Med & Hlth Sci Linkoping Sweden Linkoping Univ Ctr Med Image Sci & Visualizat CMIV Linkoping Sweden Natl Hosp Norway Oslo Univ Hosp Dept Cardiothorac Surg Oslo Norway

Purpose: To validate pressure drop measurements using 4d flow mri-based turbulence production in various shapes of stenotic stenoses. Methods: In vitro flow phantoms with seven different 3d-printed aortic valve geometries were constructed and scanned with 4d flow mri with six-directional flow encoding (ICOSA6). The pressure drop through the valve was non-invasively predicted based on the simplified Bernoulli, the extended Bernoulli, the turbulence production, and the shear-scaling methods. Linear regression and agreement of the predictions with invasively measured pressure drop were analyzed. Results: All pressure drop predictions using 4d Flow mri were linearly correlated to the true pressure drop but resulted in different regression slopes. The regression slope and 95% limits of agreement for the simplified Bernoulli method were 1.35 and 11.99 +/- 21.72 mm Hg. The regression slope and 95% limits of agreement for the extended Bernoulli method were 1.02 and 0.74 +/- 8.48 mm Hg. The regression slope and 95% limits of agreement for the turbulence production method were 0.89 and 0.96 +/- 8.01 mm Hg. The shear-scaling method presented good correlation with an invasively measured pressure drop, but the regression slope varied between 0.36 and 1.00 depending on the shear-scaling coefficient. Conclusion: The pressure drop assessment based on the turbulence production method agrees well with the extended Bernoulli method and invasively measured pressure drop in various shapes of the aortic valve. Turbulence-based pressure drop estimation can, as a complement to the conventional Bernoulli method, play a role in the assessment of valve diseases.

关键词： 4d pc-mri 4d Flow mri magnetic resonance imaging phase contrast mri pressure drop Reynolds stress turbulence

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4d Flow mri quantification of blood flow patterns, turbulence and pressure drop in normal and stenotic prosthetic heart valves

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MAGNETIC RESONANCE IMAGING 2019年 55卷 118-127页

作者： Ha, Hojin Kvitting, John-Peder Escobar dyverfeldt, Petter Ebbers, Tino Kangwon Natl Univ Dept Mech & Biomed Engn Chunchon South Korea Linkoping Univ Div Cardiovasc Med Dept Med & Hlth Sci Linkoping Sweden Linkoping Univ Ctr Med Image Sci & Visualizat CMIV Linkoping Sweden Oslo Univ Hosp Rikshosp Dept Cardiothorac Surg Oslo Norway

Purpose: To assess valvular flow characteristics and pressure drop in a variety of normal and stenotic prosthetic heart valves (PHVs) using 4d Flow mri. Materials and methods: In-vitro flow phantoms with four different PHVs were studied: Medtronic-Hall tilting disc, St. Jude Medical standard bileaflet (STJM), Medtronic CoreValve Evolut R and Edwards SAPIEN 3. The valvular flow characteristics were investigated in normal and stenotic PHVs by using 4d Flow mri. Results: The results showed that each valve provided a different amount of signal loss in the 4d Flow mri. The defect size of the signal loss from each valve was 37.5 mm, 39.0 mm, 37.5 mm and 51.0 mm for the Tilting disk, STJM, SAPIEN 3 and CoreValve, respectively. The 4d Flow mri-based estimation of the elevation of the pressure drop through the stenotic PHV using both Bernoulli-based and turbulence-based methods correlated well with the true values for the Tilting disc, STJM and SAPIEN 3 valve. However, the obstructive hemodynamics in the stenotic CoreValve was not clearly identified due to the large signal void from the long struts, resulting in a severe underestimation of the pressure drop using 4d Flow mri. Conclusion: The Tilting disc, STJM and SAPIEN 3 valves provided reasonable estimates of peak velocity, turbulence production and the corresponding pressure drop. In contrast, the large strut of the CoreValve and corresponding signal void prevented accurate measurements of the velocity and turbulence production;therefore, 4d Flow mri prediction of the pressure drop through the CoreValve was not feasible.

关键词： Turbulence Reynolds stress Pressure drop Magnetic resonance imaging Phase contrast mri 4d pc-mri 4d Flow mri

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