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Manini C, Hüllebrand M, Walczak L, Nordmeyer S, Jarmatz L, Kuehne T, Stern H, Meierhofer C, Harloff A, Erley J, Kelle S, Bannas P, Trauzeddel RF, Schulz-Menger J, Hennemuth A. Impact of training data composition on the generalizability of CNN aortic cross section segmentation in 4D Flow MRI. J Cardiovasc Magn Reson 2024:101081. [PMID: 39127260 DOI: 10.1016/j.jocmr.2024.101081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 07/08/2024] [Accepted: 08/05/2024] [Indexed: 08/12/2024] Open
Abstract
BACKGROUND Time-resolved, three-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) plays an important role in assessing cardiovascular diseases. However, the manual or semi-automatic segmentation of aortic vessel boundaries in 4D flow data introduces variability and limits reproducibility of aortic hemodynamics visualization and quantitative flow-related parameter computation. This paper explores the potential of deep learning to improve 4D flow MRI segmentation by developing models for automatic segmentation and analyzes the impact of the training data on the generalization of the model across different sites, scanner vendors, sequences, and pathologies. METHODS The study population consists of 260 4D flow MRI datasets, including subjects without known aortic pathology, healthy volunteers, and patients with bicuspid aortic valve (BAV) examined at different hospitals. The dataset was split to train segmentation models on subsets with different representations of characteristics such as pathology, gender, age, scanner model, vendor, and field strength. An enhanced 3D U-net convolutional neural network (CNN) architecture with residual units was trained for 2D+t aortic cross-sectional segmentation. The model performance was evaluated using Dice score, Hausdorff distance, and average symmetric surface distance on test data, datasets with characteristics not represented in the training set (model-specific), and an overall evaluation set. Standard diagnostic flow parameters were computed and compared with manual segmentation results using Bland-Altman analysis and interclass correlation. RESULTS The representation of technical factors such as scanner vendor and field strength in the training dataset had the strongest influence on the overall segmentation performance. Age had a greater impact than gender. Models solely trained on BAV patients' datasets performed well on datasets of healthy subjects but not vice versa. CONCLUSION This study highlights the importance of considering a heterogeneous dataset for the training of widely applicable automatic CNN segmentations in 4D flow MRI, with a particular focus on the inclusion of different pathologies and technical aspects of data acquisition.
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Affiliation(s)
- Chiara Manini
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.
| | - Markus Hüllebrand
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany; Fraunhofer MEVIS, Berlin, Germany
| | - Lars Walczak
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany; Fraunhofer MEVIS, Berlin, Germany
| | - Sarah Nordmeyer
- Department of Diagnostic and Interventional Radiology, Tübingen University Hospital, Tübingen, Germany
| | - Lina Jarmatz
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany
| | - Titus Kuehne
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany
| | - Heiko Stern
- Congenital Heart Disease and Pediatric Cardiology, German Heart Center Munich, Germany
| | - Christian Meierhofer
- Congenital Heart Disease and Pediatric Cardiology, German Heart Center Munich, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, University Medical Center Freiburg - Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jennifer Erley
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany; Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Corporate Member of Freie Universität Berlin and Humboldt - Universität zu Berlin, Berlin, Germany
| | - Sebastian Kelle
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany; Department of Cardiology, Angiology and Intensive Care Medicine, Deutsches Herzzentrum der Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Corporate Member of Freie Universität Berlin and Humboldt - Universität zu Berlin, Berlin, Germany
| | - Peter Bannas
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Germany
| | - Ralf Felix Trauzeddel
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125 Berlin, Germany; Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité - Universitätsmedizin Berlin and the Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Anesthesiology and Intensive Care Medicine, Charité Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Jeanette Schulz-Menger
- German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, ECRC Experimental and Clinical Research Center, Lindenberger Weg 80, 13125 Berlin, Germany; Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité - Universitätsmedizin Berlin and the Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Department of Cardiology and Nephrology, Helios Hospital Berlin-Buch, Berlin, Germany
| | - Anja Hennemuth
- Deutsches Herzzentrum der Charité (DHZC), Institute of Computer-assisted Cardiovascular Medicine, Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany; Fraunhofer MEVIS, Berlin, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Germany; Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Germany
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Strecker C, Kopczak A, Saam T, Sepp D, Hennemuth A, Mayerhofer E, Poli S, Ziemann U, Poppert H, Schindler A, Harloff A. Carotid geometry is independently associated with complicated carotid artery plaques. Front Cardiovasc Med 2023; 10:1177998. [PMID: 37378412 PMCID: PMC10291134 DOI: 10.3389/fcvm.2023.1177998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Introduction Complicated carotid artery plaques (cCAPs) are associated with an increased risk of rupture and subsequent stroke. The geometry of the carotid bifurcation determines the distribution of local hemodynamics and could thus contribute to the development and composition of these plaques. Therefore, we studied the role of carotid bifurcation geometry in the presence of cCAPs. Methods We investigated the association of individual vessel geometry with carotid artery plaque types in the Carotid Plaque Imaging in Acute Stroke (CAPIAS) study. After excluding arteries without plaque or with insufficient MRI quality, 354 carotid arteries from 182 patients were analyzed. Individual parameters of carotid geometry [i.e., internal carotid artery (ICA)/common carotid artery (CCA) ratio, bifurcation angle, and tortuosity) were derived from time-of-flight MR images. The lesion types of carotid artery plaques were determined according to the American Heart Association classification of lesions by multi-contrast 3T-MRI. The association between carotid geometry and a cCAP was studied using logistic regression after adjusting for age, sex, wall area, and cardiovascular risk factors. Results Low ICA/CCA ratios (OR per SD increase 0.60 [95%CI: 0.42-0.85]; p = 0.004) and low bifurcation angles (OR 0.61 [95%CI: 0.42-0.90]; p = 0.012) were significantly associated with the presence of cCAPs after adjusting for age, sex, cardiovascular risk factors, and wall area. Tortuosity had no significant association with cCAPs. Only ICA/CCA ratio remained significant in a model containing all three geometric parameters (OR per SD increase 0.65 [95%CI: 0.45-0.94]; p = 0.023). Conclusions A steep tapering of the ICA relative to the CCA and, to a lesser extent, a low angle of the carotid bifurcation were associated with the presence of cCAPs. Our findings highlight the contribution of bifurcation geometry to plaque vulnerability. Thus, assessment of carotid geometry could be helpful in identifying patients at risk of cCAPs.
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Affiliation(s)
- Christoph Strecker
- Department of Neurology and Neurophysiology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anna Kopczak
- Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany
| | | | - Dominik Sepp
- Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany
| | - Anja Hennemuth
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ernst Mayerhofer
- Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Sven Poli
- Department of Neurology and Stroke and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ulf Ziemann
- Department of Neurology and Stroke and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Poppert
- Department of Neurology, Helios Klinikum München West, Munich, Germany
| | - Andreas Schindler
- Institute of Neuroradiology, University Hospital, LMU Munich, Munich, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Loose S, Solou D, Strecker C, Hennemuth A, Hüllebrand M, Grundmann S, Asmussen A, Treppner M, Urbach H, Harloff A. Characterization of aortic aging using 3D multi-parametric MRI-long-term follow-up in a population study. Sci Rep 2023; 13:6285. [PMID: 37072440 PMCID: PMC10111081 DOI: 10.1038/s41598-023-33219-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 04/10/2023] [Indexed: 05/03/2023] Open
Abstract
We comprehensively studied morphological and functional aortic aging in a population study using modern three-dimensional MR imaging to allow future comparison in patients with diseases of the aortic valve or aorta. We followed 80 of 126 subjects of a population study (20 to 80 years of age at baseline) using the identical methodology 6.0 ± 0.5 years later. All underwent 3 T MRI of the thoracic aorta including 3D T1 weighted MRI (spatial resolution 1 mm3) for measuring aortic diameter and plaque thickness and 4D flow MRI (spatial/temporal resolution = 2 mm3/20 ms) for calculating global and regional aortic pulse wave velocity (PWV) and helicity of aortic blood flow. Mean diameter of the ascending aorta (AAo) decreased and plaque thickness increased significantly in the aortic arch (AA) and descending aorta (DAo) in females. PWV of the thoracic aorta increased (6.4 ± 1.5 to 7.0 ± 1.7 m/s and 6.8 ± 1.5 to 7.3 ± 1.8 m/s in females and males, respectively) over time. Local normalized helicity volumes (LNHV) decreased significantly in the AAo and AA (0.33 to 0.31 and 0.34 to 0.32 in females and 0.34 to 0.32 and 0.32 to 0.28 in males). By contrast, helicity increased significantly in the DAo in both genders (0.28 to 0.29 and 0.29 to 0.30, respectively). 3D MRI was able to characterize changes in aortic diameter, plaque thickness, PWV and helicity during six years in our population. Aortic aging determined by 3D multi-parametric MRI is now available for future comparisons in patients with diseases of the aortic valve or aorta.
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Affiliation(s)
- Sophie Loose
- Department of Neurology and Neurophysiology, University Medical Center Freiburg, University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Demetris Solou
- Department of Neurology and Neurophysiology, University Medical Center Freiburg, University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christoph Strecker
- Department of Neurology and Neurophysiology, University Medical Center Freiburg, University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Fraunhofer MEVIS, Bremen, Germany
- Institute of Computer-Assisted Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Hüllebrand
- Fraunhofer MEVIS, Bremen, Germany
- Institute of Computer-Assisted Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Grundmann
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Cardiology and Angiology I, Heart Center Freiburg University, University of Freiburg, Freiburg, Germany
| | - Alexander Asmussen
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Cardiology and Angiology I, Heart Center Freiburg University, University of Freiburg, Freiburg, Germany
| | - Martin Treppner
- Institute of Medical Biometry and Statistics, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Horst Urbach
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Neuroradiology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, University Medical Center Freiburg, University of Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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Wehrum T, Dragonu I, Strecker C, Hennemuth A, Hennig J, Reinhard T, Harloff A. Influence of Pulse Wave Velocity on Atherosclerosis and Blood Flow Reversal in the Aorta: A 4-Dimensional Flow Magnetic Resonance Imaging Study in Acute Stroke Patients and Matched Controls. J Thorac Imaging 2022; 37:42-48. [PMID: 33492047 DOI: 10.1097/rti.0000000000000580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Aortic stiffness is associated with a higher incidence of cardiovascular events including stroke. The primary aim of this study was to evaluate whether increased pulse wave velocity (PWV), a marker of stiffness, is an independent predictor of aortic atheroma. The secondary aim was to test whether increased PWV reinforces retrograde blood flow from the descending aorta (DAo), a mechanism of stroke. METHODS We performed a cross-sectional case-control study with prospective data acquisition. In all, 40 stroke and 60 ophthalmic patients matched for age and cardiovascular risk factors were included. Multicontrast magnetic resonance imaging (MRI) protocol of the aorta tailored to allow a detailed plaque analysis using 3-dimensional (D) T1-weighted bright blood, T2-weighted and proton density-weighted black blood, and hemodynamic assessment using 4D flow MRI was applied. Individual PWV was calculated based on 4D flow MRI data using the time-to-foot of the blood flow waveform. The extent of maximum retrograde blood flow from the proximal DAo into the arch was quantified. RESULTS PWV was higher in stroke patients compared with controls (7.62±2.59 vs. 5.96±2.49 m/s; P=0.005) and in patients with plaques (irrespective of thickness) compared with patients without plaques (7.47±2.89 vs. 5.62±1.89 m/s; P=0.002). Increased PWV was an independent predictor of plaque prevalence and contributed significantly to a predictor model explaining 36.5% (Nagelkerke R2) of the variance in plaque presence. Maximum retrograde flow extent from the proximal DAo was not correlated with PWV. CONCLUSIONS Aortic stiffness was higher in stroke patients and associated with a higher prevalence of plaques. Increased PWV was an independent predictor of plaque presence. Accordingly, regional PWV seems to be a valuable biomarker for the assessment and management of aortic atherosclerosis. However, no association was found for increased retrograde flow extent from the DAo.
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Affiliation(s)
| | - Iulius Dragonu
- Departments of Neurology
- Radiology-Medical Physics, Medical Center
| | | | - Anja Hennemuth
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Thomas Reinhard
- Eye Center, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
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5
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Strecker C, Krafft AJ, Kaufhold L, Hüllebrandt M, Treppner M, Ludwig U, Köber G, Hennemuth A, Hennig J, Harloff A. Carotid Geometry and Wall Shear Stress Independently Predict Increased Wall Thickness-A Longitudinal 3D MRI Study in High-Risk Patients. Front Cardiovasc Med 2021; 8:723860. [PMID: 34765650 PMCID: PMC8576112 DOI: 10.3389/fcvm.2021.723860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Carotid geometry and wall shear stress (WSS) have been proposed as independent risk factors for the progression of carotid atherosclerosis, but this has not yet been demonstrated in larger longitudinal studies. Therefore, we investigated the impact of these biomarkers on carotid wall thickness in patients with high cardiovascular risk. Methods: Ninety-seven consecutive patients with hypertension, at least one additional cardiovascular risk factor and internal carotid artery (ICA) plaques (wall thickness ≥ 1.5 mm and degree of stenosis ≤ 50%) were prospectively included. They underwent high-resolution 3D multi-contrast and 4D flow MRI at 3 Tesla both at baseline and follow-up. Geometry (ICA/common carotid artery (CCA)-diameter ratio, bifurcation angle, tortuosity and wall thickness) and hemodynamics [WSS, oscillatory shear index (OSI)] of both carotid bifurcations were measured at baseline. Their predictive value for changes of wall thickness 12 months later was calculated using linear regression analysis for the entire study cohort (group 1, 97 patients) and after excluding patients with ICA stenosis ≥10% to rule out relevant inward remodeling (group 2, 61 patients). Results: In group 1, only tortuosity at baseline was independently associated with carotid wall thickness at follow-up (regression coefficient = −0.52, p < 0.001). However, after excluding patients with ICA stenosis ≥10% in group 2, both ICA/CCA-ratio (0.49, p < 0.001), bifurcation angle (0.04, p = 0.001), tortuosity (−0.30, p = 0.040), and WSS (−0.03, p = 0.010) at baseline were independently associated with changes of carotid wall thickness at follow-up. Conclusions: A large ICA bulb and bifurcation angle and low WSS seem to be independent risk factors for the progression of carotid atherosclerosis in the absence of ICA stenosis. By contrast, a high carotid tortuosity seems to be protective both in patients without and with ICA stenosis. These biomarkers may be helpful for the identification of patients who are at particular risk of wall thickness progression and who may benefit from intensified monitoring and treatment.
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Affiliation(s)
- Christoph Strecker
- Department of Neurology and Neurophysiology, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Axel Joachim Krafft
- Department of Radiology-Medical Physics, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Lilli Kaufhold
- Fraunhofer MEVIS, Bremen, Germany.,Institute for Imaging Science and Computational Modeling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Hüllebrandt
- Fraunhofer MEVIS, Bremen, Germany.,Institute for Imaging Science and Computational Modeling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Treppner
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- Department of Radiology-Medical Physics, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Göran Köber
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Fraunhofer MEVIS, Bremen, Germany.,Institute for Imaging Science and Computational Modeling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Hennig
- Department of Radiology-Medical Physics, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, Freiburg, Germany
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Visualization of Quantitative Flow Reduction with 4D-flow Magnetic Resonance Imaging in a Patient with Pelvic Arteriovenous Malformation After Transcatheter Arterial Embolization. Cardiovasc Intervent Radiol 2020; 43:1557-1560. [DOI: 10.1007/s00270-020-02545-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/29/2020] [Indexed: 10/24/2022]
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7
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Strecker C, Krafft AJ, Kaufhold L, Hüllebrandt M, Weber S, Ludwig U, Wolkewitz M, Hennemuth A, Hennig J, Harloff A. Carotid geometry is an independent predictor of wall thickness - a 3D cardiovascular magnetic resonance study in patients with high cardiovascular risk. J Cardiovasc Magn Reson 2020; 22:67. [PMID: 32912285 PMCID: PMC7488078 DOI: 10.1186/s12968-020-00657-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/28/2020] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The posterior wall of the proximal internal carotid artery (ICA) is the predilection site for the development of stenosis. To optimally prevent stroke, identification of new risk factors for plaque progression is of high interest. Therefore, we studied the impact of carotid geometry and wall shear stress on cardiovascular magnetic resonance (CMR)-depicted wall thickness in the ICA of patients with high cardiovascular disease risk. METHODS One hundred twenty-one consecutive patients ≥50 years with hypertension, ≥1 additional cardiovascular risk factor and ICA plaque ≥1.5 mm thickness and < 50% stenosis were prospectively included. High-resolution 3D-multi-contrast (time of flight, T1, T2, proton density) and 4D flow CMR were performed for the assessment of morphological (bifurcation angle, ICA/common carotid artery (CCA) diameter ratio, tortuosity, and wall thickness) and hemodynamic parameters (absolute/systolic wall shear stress (WSS), oscillatory shear index (OSI)) in 242 carotid bifurcations. RESULTS We found lower absolute/systolic WSS, higher OSI and increased wall thickness in the posterior compared to the anterior wall of the ICA bulb (p < 0.001), whereas this correlation disappeared in ≥10% stenosis. Higher carotid tortuosity (regression coefficient = 0.764; p < 0.001) and lower ICA/CCA diameter ratio (regression coefficient = - 0.302; p < 0.001) were independent predictors of increased wall thickness even after adjustment for cardiovascular risk factors. This association was not found for bifurcation angle, WSS or OSI in multivariate regression analysis. CONCLUSIONS High carotid tortuosity and low ICA diameter were independent predictors for wall thickness of the ICA bulb in this cross-sectional study, whereas this association was not present for WSS or OSI. Thus, consideration of geometric parameters of the carotid bifurcation could be helpful to identify patients at increased risk of carotid plaque generation. However, this association and the potential benefit of WSS measurement need to be further explored in a longitudinal study.
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Affiliation(s)
- Christoph Strecker
- Department of Neurology and Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
| | - Axel Joachim Krafft
- Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lilli Kaufhold
- Fraunhofer MEVIS, Bremen, Germany
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Hüllebrandt
- Fraunhofer MEVIS, Bremen, Germany
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne Weber
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Wolkewitz
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Fraunhofer MEVIS, Bremen, Germany
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Hennig
- Department of Radiology - Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany
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8
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Harloff A, Hagenlocher P, Lodemann T, Hennemuth A, Weiller C, Hennig J, Vach W. Retrograde aortic blood flow as a mechanism of stroke: MR evaluation of the prevalence in a population-based study. Eur Radiol 2019; 29:5172-5179. [PMID: 30877458 DOI: 10.1007/s00330-019-06104-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/07/2019] [Accepted: 02/12/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Retrograde blood flow from complex atheroma in the descending aorta (DAo) has only recently been described as a potential mechanism of stroke. However, prevalence of this mechanism in the general population and the exact factors influencing stroke risk are unclear. METHODS One hundred twenty-six consecutively recruited inhabitants of Freiburg, Germany, between 20 and 80 years of age prospectively underwent 3-T MRI. Aortic plaque location and thickness were determined by 3D T1 MRI (1 mm3). 4D flow MRI (spatial/temporal resolution 2 mm3/20 ms) and dedicated software were used to determine prevalence and extent of flow reversal and potential embolization from DAo plaques. Flow was correlated with baseline characteristics and echocardiographic and MRI parameters (aortic diameter, wall thickness, and pulse wave velocity). RESULTS The maximum length of retrograde blood flow connecting the DAo with the left subclavian artery (LSA) increased from 16.1 ± 8.3 mm in 20-29-year-old to 24.7 ± 11.7 mm in 70-80-year-old subjects, correlated with age (r = 0.37; p < 0.001), and was lower in females (p = 0.003). Age was the only independent predictor of increased flow reversal. Complex DAo plaques ≥ 4-mm thickness were found in eight subjects (6.3%) and were connected with the LSA, left common carotid artery, and brachiocephalic trunk in 8 (100%), 1 (12.5%), and 0 (0%) cases, respectively. CONCLUSIONS Retrograde blood flow from the DAo was very frequent. However, potential retrograde embolization was rare due to the low incidence of complex DAo plaques. The magnitude of flow reversal and prevalence of complex atheroma increased with age. Thus, older patients with aortic atherosclerosis are especially vulnerable to this stroke mechanism. KEY POINTS • 4D flow MRI allows in vivo visualization and quantification of individual and three-dimensional blood flow patterns within the thoracic aorta including retrograde components. • This population-based study showed that blood flow reversal from the proximal descending aorta to the brain-supplying great arteries is very frequent and able to reach all brain territories. The extent of such flow reversal increases with age and with the extent of aortic atherosclerosis. • The combination of blood flow reversal with plaque rupture in the proximal descending aorta constitutes a potential stroke mechanism that should be considered in future trials and in the management of stroke patients in clinical routine.
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Affiliation(s)
- Andreas Harloff
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Breisacherstr. 64, 79106, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Paul Hagenlocher
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Breisacherstr. 64, 79106, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Lodemann
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Breisacherstr. 64, 79106, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Institute for Cardiovascular Computer-Assisted Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Cornelius Weiller
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Breisacherstr. 64, 79106, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Department of Diagnostic Radiology, MR Physics, Medical Center - University of Freiburg, Freiburg, Germany
| | - Werner Vach
- Institute for Medical Biometry and Statistics, Medical Faculty and Medical Center, University of Freiburg, Freiburg, Germany.,Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland
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Harloff A, Mirzaee H, Lodemann T, Hagenlocher P, Wehrum T, Stuplich J, Hennemuth A, Hennig J, Grundmann S, Vach W. Determination of aortic stiffness using 4D flow cardiovascular magnetic resonance - a population-based study. J Cardiovasc Magn Reson 2018; 20:43. [PMID: 29925388 PMCID: PMC6011486 DOI: 10.1186/s12968-018-0461-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Increased aortic stiffness is an independent predictor of cardiovascular disease. Optimal measurement is highly beneficial for the detection of atherosclerosis and the management of patients at risk. Thus, it was our purpose to selectively measure aortic stiffness using a novel imaging method and to provide reference values from a population-based study. METHODS One hundred twenty six inhabitants of Freiburg, Germany, between 20 and 80 years prospectively underwent 3 Tesla cardiovascular magnetic resonance (CMR) of the thoracic aorta. 4D flow CMR (spatial/temporal resolution 2mm3/20ms) was executed to calculate aortic pulse wave velocity (PWV) in m/s using dedicated software. In addition, we calculated distensibility coefficients (DC) using 2D CINE CMR imaging of the ascending (AAo) and descending aorta (DAo). Segmental aortic diameter and thickness of aortic plaques were determined by 3D T1 weighted CMR (spatial resolution 1mm3). RESULTS PWV increased from 4.93 ± 0.54 m/s in 20-30 year-old to 8.06 ± 1.03 m/s in 70-80 year-old subjects. PWV was significantly lower in women compared to men (p < 0.0001). Increased blood pressure (systolic r = 0.36, p < 0.0001; diastolic r = 0.33, p = 0.0001; mean arterial pressure r = 0.37, p < 0.0001) correlated with PWV after adjustment for age and gender. Finally, PWV increased with increasing diameter of the aorta (ascending aorta r = 0.20, p = 0.026; aortic arch r = 0.24, p = 0.009; descending aorta r = 0.26, p = 0.004). Correlation of PWV and DC of the AAo and DAo or the mean of both was high (r = 0.69, r = 0.68, r = 0.73; p < 0.001). CONCLUSIONS 4D flow CMR was successfully applied to calculate aortic PWV and thus aortic stiffness. Findings showed a high correlation with distensibility coefficients representing local compliance of the aorta. Our novel method and reference data for PWV may provide a reliable biomarker for the identification of patients with underlying cardiovascular disease and optimal guidance of future treatment in studies or clinical routine.
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Affiliation(s)
- Andreas Harloff
- Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | | | - Thomas Lodemann
- Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Paul Hagenlocher
- Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Thomas Wehrum
- Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Judith Stuplich
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Cardiology and Angiology I, Heart Center Freiburg University, University of Freiburg, Freiburg im Breisgau, Germany
| | - Anja Hennemuth
- Fraunhofer MEVIS, Bremen, Germany
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Hennig
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Diagnostic Radiology – MR Physics, Medical Center - University of Freiburg, Freiburg im Breisgau, Germany
| | - Sebastian Grundmann
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Cardiology and Angiology I, Heart Center Freiburg University, University of Freiburg, Freiburg im Breisgau, Germany
| | - Werner Vach
- Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Orthopedics & Traumatology, University Hospital Basel, Basel, Switzerland
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10
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Wehrum T, Lodemann T, Hagenlocher P, Stuplich J, Ngo BTT, Grundmann S, Hennemuth A, Hennig J, Harloff A. Age-related changes of right atrial morphology and inflow pattern assessed using 4D flow cardiovascular magnetic resonance: results of a population-based study. J Cardiovasc Magn Reson 2018; 20:38. [PMID: 29898733 PMCID: PMC6001162 DOI: 10.1186/s12968-018-0456-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 05/08/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To assess age-related changes of blood flow and geometry of the caval veins and right atrium (RA) using 4D flow cardiovascular magnetic resonance (CMR) data obtained in a population-based study. METHODS An age-stratified sample (n = 126) of the population of the city of Freiburg, Germany, underwent transthoracic echocardiography and electrocardiogram-triggered and navigator-gated 4D flow CMR at 3 Tesla covering the caval veins and right heart. Study participants were divided into three age groups (1:20-39; 2:40-59; and 3:60-80 years of age). Analysis planes were placed in the superior and inferior caval vein. Subsequently, RA morphology and three-dimensional blood inflow pattern was assessed. RESULTS Blood flow of the RA showed a clockwise rotating helix without signs of turbulence in younger subjects. By contrast, such rotation was absent in 12 subjects of group 3 and turbulences were significantly more frequent (p < 0.001). We observed an age-related shift of the caval vein axis. While the outlets of the superior and inferior caval veins were facing each other in group 1, lateralization occurred in older subjects (p < 0.001). A convergence of axes was observed from lateral view with facing axes in older subjects (p = 0.004). Finally, mean and peak systolic blood flow in the caval veins decreased with age (group 3 < 2 < 1). CONCLUSIONS We have provided reference values of 4D CMR blood flow for different age groups and demonstrated the significant impact of age on hemodynamics of the RA inflow tract. This effect of aging should be taken into account when assessing pathologic conditions of the heart in the future.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology and Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
| | - Thomas Lodemann
- Department of Neurology and Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
| | - Paul Hagenlocher
- Department of Neurology and Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
| | - Judith Stuplich
- Department of Cardiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ba Thanh Truc Ngo
- Department of Cardiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian Grundmann
- Department of Cardiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anja Hennemuth
- Charité – Universitätsmedizin Berlin, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Berlin, Germany
| | - Jürgen Hennig
- Department of Diagnostic Radiology – Medical Physics, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neuroscience, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
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Wehrum T, Günther F, Kams M, Wendel S, Strecker C, Mirzaee H, Harloff A. Quantification of aortic stiffness in stroke patients using 4D flow MRI in comparison with transesophageal echocardiography. Int J Cardiovasc Imaging 2018; 34:1629-1636. [PMID: 29799061 DOI: 10.1007/s10554-018-1369-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 05/16/2018] [Indexed: 01/09/2023]
Abstract
To quantify stiffness of the descending aorta (DAo) in stroke patients using 4D flow MRI and compare results with transesophageal echocardiography (TEE). 48 acute stroke patients undergoing 4D flow MRI and TEE were included. Intima-media-thickness (IMT) was measured in the DAo and the aorta was scrutinized for atherosclerotic plaques using TEE. Stiffness of the DAo was determined by (a) 4D flow MRI at 3 T by calculating pulse wave velocity (PWV) and by (b) TEE calculating arterial strain, stiffness index, and distensibility coefficient. Mean IMT was 1.43 ± 1.75. 7 (14.6%) subjects had no sign of atherosclerosis, 10 (20.8%) had IMT-thickening or plaques < 4 mm, and 31 (66.7%) had at least one large and/or complex plaque in the aorta. Increased IMT significantly correlated (p < 0.001) with increased DAo stiffness in MRI (PWV r = 0.66) and in TEE (strain r = 0.57, stiffness index r = 0.64, distensibility coefficient r = 0.57). Patients with at least IMT-thickening had significantly higher stiffness values compared to patients without atherosclerosis. However, no difference was observed between patients with plaques < 4 mm and patients with plaques ≥ 4 mm. PWV and TEE parameters of stiffness correlated significantly [strain (r = - 0.36; p = 0.011), stiffness index (r = 0.51; p = 0.002), and distensibility coefficient (r = - 0.59; p < 0.001)]. 4D flow MRI and TEE-based parameters of aortic stiffness were associated with markers of atherosclerosis such as IMT-thickness and presence of plaques. We believe that 4D flow MRI is a promising tool for future studies of aortic atherosclerosis, due to its longer coverage of the aorta and non-invasiveness.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology and Clinical Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Felix Günther
- Department of Cardiology and Angiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Miriam Kams
- Department of Neurology and Clinical Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sarah Wendel
- Department of Neurology and Clinical Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christoph Strecker
- Department of Neurology and Clinical Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Andreas Harloff
- Department of Neurology and Clinical Neurophysiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Wehrum T, Guenther F, Fuchs A, Schuchardt F, Hennemuth A, Harloff A. Measurement of cardiac valve and aortic blood flow velocities in stroke patients: a comparison of 4D flow MRI and echocardiography. Int J Cardiovasc Imaging 2018; 34:939-946. [DOI: 10.1007/s10554-018-1298-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/04/2018] [Indexed: 11/30/2022]
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13
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Wehrum T, Dragonu I, Strecker C, Schuchardt F, Hennemuth A, Drexl J, Reinhard T, Böhringer D, Vach W, Hennig J, Harloff A. Aortic atheroma as a source of stroke - assessment of embolization risk using 3D CMR in stroke patients and controls. J Cardiovasc Magn Reson 2017; 19:67. [PMID: 28877718 PMCID: PMC5586056 DOI: 10.1186/s12968-017-0379-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/10/2017] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND It was our purpose to identify vulnerable plaques in the thoracic aorta using 3D multi-contrast CMR and estimate the risk of cerebral embolization using 4D flow CMR in cryptogenic stroke patients and controls. METHODS One hundred patients (40 with cryptogenic stroke, 60 ophthalmologic controls matched for age, sex and presence of hypertension) underwent a novel 3D multi-contrast (T1w, T2w, PDw) CMR protocol at 3 Tesla for plaque detection and characterization within the thoracic aorta, which was combined with 4D flow CMR for mapping potential embolization pathways. Plaque morphology was assessed in consensus reading by two investigators and classified according to the modified American-Heart-Association (AHA) classification of atherosclerotic plaques. RESULTS In the thoracic aorta, plaques <4 mm thickness were found in a similar number of stroke patients and controls [23 (57.5%) versus 33 (55.0%); p = 0.81]. However, plaques ≥4 mm were more frequent in stroke patients [22 (55.0%) versus 10 (16.7%); p < 0.001]. Of those patients with plaques ≥4 mm, seven (17.5%) stroke patients and two (3.3%) controls (p < 0.001) had potentially vulnerable AHA type VI plaques. Six stroke patients with vulnerable AHA type VI plaques ≥4 mm had potential embolization pathways connecting the plaque, located in the aortic arch (n = 3) and proximal descending aorta (n = 3), with the individual territory of stroke, which made them the most likely source of stroke in those patients. CONCLUSIONS Our findings underline the significance of ≥4 mm thick and vulnerable plaques in the aortic arch and descending aorta as a relevant etiology of stroke. CLINICAL TRIAL REGISTRATION Unique identifier: DRKS00006234 ; date of registration: 11/06/2014.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Iulius Dragonu
- Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Diagnostic Radiology – Medical Physics, Medical Center, University of Freiburg, Freiburg, Germany
| | - Christoph Strecker
- Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Florian Schuchardt
- Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | | | - Thomas Reinhard
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Eye Center, Medical Center, University of Freiburg, Freiburg, Germany
| | - Daniel Böhringer
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Eye Center, Medical Center, University of Freiburg, Freiburg, Germany
| | - Werner Vach
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Diagnostic Radiology – Medical Physics, Medical Center, University of Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology, Medical Center - University of Freiburg, Breisacher Straße 64, 79106 Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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14
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Wehrum T, Dragonu I, Strecker C, Hennig J, Harloff A. Multi-contrast and three-dimensional assessment of the aortic wall using 3T MRI. Eur J Radiol 2017. [PMID: 28629561 DOI: 10.1016/j.ejrad.2017.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To develop a 3D-multi-contrast MRI protocol allowing for high resolution imaging of the wall and of atheroma in the thoracic aorta. METHODS Eleven healthy volunteers and eleven acute stroke patients with aortic plaques detected by TEE underwent MRI at 3T. The MRI-protocol consisted of a T1w-bright-blood, a T2w- and a PDw-black-blood sequence (spatial resolution=1.15mm3). Image quality was assessed by two blinded investigators using a 3-point score and intra- and inter-rater agreement was tested. In patients, atherosclerotic plaques were graded according to the modified American Heart Association (AHA) classification. RESULTS Total examination time was 35:42±7:48min in volunteers and 41:07±3:15min in patients. Image quality was graded with the highest score in 80-94% of T1w, 89-96% of T2w and 79-86% of PDw datasets. Intra- and inter-rater reliability regarding image quality grading was high. Five stroke patients showed AHA type III lesions, three had AHA type VII and two had type VIII plaques. One patient had a vulnerable appearing AHA VI plaque. CONCLUSIONS 3D-multi-contrast MR-imaging of the aorta was performed with high image quality and in reasonable time. It allows evaluation of atherosclerotic plaque composition throughout the aortic arch and can be used to identify vulnerable plaques in acute stroke patients.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Germany.
| | - Iulius Dragonu
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Germany; Department of Radiology - MR Physics, Medical Center, University of Freiburg, Germany
| | - Christoph Strecker
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Germany
| | - Jürgen Hennig
- Department of Radiology - MR Physics, Medical Center, University of Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Germany
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15
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Wehrum T, Guenther F, Vach W, Gladstone BP, Wendel S, Fuchs A, Wu K, Maurer CJ, Harloff A. Aortic Atherosclerosis Determines Increased Retrograde Blood Flow as a Potential Mechanism of Retrograde Embolic Stroke. Cerebrovasc Dis 2017; 43:132-138. [PMID: 28049202 DOI: 10.1159/000455053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/05/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Retrograde brain embolization from complex plaques of the proximal descending aorta (DAo) has been identified as a new potential mechanism of stroke. Our purpose was to identify predictors of increased retrograde aortic blood flow indicating an elevated risk of brain embolization from the DAo. METHODS A total of 485 patients with acute ischemic stroke were prospectively included and underwent transesophageal echocardiography. Blood flow velocities in the proximal DAo were studied using 2D pulse-wave Doppler ultrasound. Velocity-time integrals (VTI) were calculated for antegrade and retrograde velocity directions. The ratio (VTIretrograde/VTIantegrade) was used to estimate retrograde flow extent. Associations between patient demographics, cardiovascular risk factors, echocardiographic parameters, and VTIratio were analyzed using multivariate linear regression. RESULTS Retrograde blood flow in the DAo occurred in all patients. Velocity profiles in the proximal DAo were as follows (mean ± SD): VTIantegrade = 21.1 ± 6.5, VTIretrograde = 11.0 ± 3.6, and VTIratio = 0.54 ± 0.16. Diameter (r = 0.25, p < 0.001), presence of complex plaques (r = 0.12, p = 0.007), and reduced strain of the DAo (r = -0.23, p < 0.001) had significant partial effects in a predictor model based on predefined variables, which predicted 26% (adjusted R2 = 0.26) of the variance in VTIratio. A unit increase in the DAo diameter was associated with a 2% increase in VTIratio (95% CI 1-2.8%, p < 0.001). Presence of complex plaques increased VTIratio by 7% (95% CI 2-13%, p = 0.007) and an increase in strain by 0.1 indicated a decrease in VTIratio by about 11% (95% CI 6.2-15.5%, p < 0.001). Complex atheroma was found in the proximal DAo of 79 subjects, of which 40 (50.6%) had a VTIratio above average (VTIratio ≥0.54) compared to 87 of 261 (33.3%) patients without any complex plaques (p < 0.001). Twenty-five of 79 (31.7%) patients with complex DAo plaques had a VTIratio ≥0.60, which indicates a high likelihood of retrograde pathline length of ≥3 cm and thus increased risk of retrograde cerebral embolization. Stroke etiology of those 25 patients was determined in 13 and cryptogenic in 12 cases. CONCLUSIONS Retrograde blood flow in the DAo was found in all stroke patients. However, it increased further in patients with concomitant complex plaques, low strain, and/or large aortic diameter, that is, in those with atherosclerosis of the DAo. Accordingly, such patients may be predisposed to retrograde embolization in case of occurrence of a complex plaque in proximity to a brain-supplying artery.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology, University Medical Center Freiburg, Freiburg, Germany
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16
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Wehrum T, Hagenlocher P, Lodemann T, Vach W, Dragonu I, Hennemuth A, von Zur Mühlen C, Stuplich J, Ngo BTT, Harloff A. Age dependence of pulmonary artery blood flow measured by 4D flow cardiovascular magnetic resonance: results of a population-based study. J Cardiovasc Magn Reson 2016; 18:31. [PMID: 27245203 PMCID: PMC4888740 DOI: 10.1186/s12968-016-0252-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/19/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND It was our aim to systematically analyze pulmonary artery blood flow within different age-groups in the general population using 4D flow cardiovascular magnetic resonance (CMR) in order to provide a context for interpreting results of future studies (e.g., in pulmonary hypertension) using this technique. METHODS An age-stratified sample (n = 126) of the population of the city of Freiburg, Germany, underwent ECG-triggered and navigator-gated 4D flow CMR at 3 T of the pulmonary arteries and the thoracic aorta. Analysis planes were placed in the main, left, and right pulmonary artery using dedicated software. Study participants were divided into three groups (1:20-39; 2:40-59; and 3:60-80 years of age). Subsequently, pulmonary blood flow was visualized, quantified and compared between groups. RESULTS Time-to-peak of systolic antegrade flow was shorter, peak and average velocities and flow volumes were lower in older subjects. At the end of systole, retrograde flow in the main pulmonary artery was observed in all but one subject. Subsequently, a second antegrade flow peak occurred in diastole which was lower in older subjects. Age was an independent predictor of hemodynamic change after adjustment for cardiovascular risk factors and body-mass-index. During systole, abnormal vortices occurred in the main pulmonary artery in four male subjects. CONCLUSIONS Comprehensive analysis of pulmonary blood flow was feasible in all subjects. We were able to detect an independent effect of ageing on pulmonary hemodynamics reflecting increased vessel stiffness and reduced pulmonary circulation. Findings of this study may be helpful for discriminating physiological from pathological flow in patients with pulmonary diseases in the future.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology, University Medical Center Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany.
| | - Paul Hagenlocher
- Department of Neurology, University Medical Center Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
| | - Thomas Lodemann
- Department of Neurology, University Medical Center Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
| | - Werner Vach
- Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg, Germany
| | - Iulius Dragonu
- Department of Diagnostic Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | | | | | - Judith Stuplich
- Department of Cardiology, University Heart Center Freiburg, Freiburg, Germany
| | - Ba Thanh Truc Ngo
- Department of Cardiology, University Heart Center Freiburg, Freiburg, Germany
| | - Andreas Harloff
- Department of Neurology, University Medical Center Freiburg, Breisacher Straße 64, 79106, Freiburg, Germany
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Wehrum T, Kams M, Günther F, Beryl P, Vach W, Dragonu I, Harloff A. Quantification of Retrograde Blood Flow in the Descending Aorta Using Transesophageal Echocardiography in Comparison to 4D Flow MRI. Cerebrovasc Dis 2015; 39:287-92. [PMID: 25896851 DOI: 10.1159/000381682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/16/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Retrograde diastolic blood flow in the proximal descending aorta (DAo), which connects plaques ≥4 mm thickness with brain-supplying arteries, has previously been identified as a possible source of brain embolism. Currently, only 4D flow MRI is able to visualize and quantify potential retrograde embolization pathways in the DAo in-vivo. Hence, it was our aim to test if the extent of retrograde flow could be estimated by routine 2D transesophageal echocardiography (TEE). METHODS Forty-eight acute stroke patients were prospectively included and they underwent Doppler examinations of the transition zone between the aortic arch and the DAo using a 20 mm 2D sample volume in longitudinal section at 90-140° Doppler angle during routine TEE. Velocity-time-integrals (VTI) were studied for antegrade and retrograde velocities and the ratio (VTIratio) was calculated and correlated with the length of retrograde pathlines at that site, which were visualized using 4D flow MRI at 3-Tesla. A receiver operating characteristic (ROC) curve was used to evaluate a threshold value of VTIratio in differentiating large (≥3 cm) from small (<3 cm) retrograde flow extent. RESULTS At the TEE measurement site, the mean VTIratio was 0.53 ± 0.16 and the mean length of retrograde pathlines reaching back into the aortic arch was 3.1 ± 1.4 cm. VTIratio was an independent predictor of retrograde pathline length (r = 0.44; p = 0.002). ROC analysis identified a VTIratio threshold value of 0.6012 with a sensitivity of 0.5, a specificity of 0.92, and positive and negative predictive values of 0.84 and 0.68, respectively. Accordingly, 11 (22.91%) patients had a VTIratio cutoff value ≥0.6012 and corresponding retrograde pathline length ≥3 cm in 4D flow MRI. CONCLUSIONS TEE allows predicting the length of retrograde pathlines. Hence, it may offer a cost-effective way to investigate independent predictors of DAo flow reversal in large-scale studies. However, TEE is only of limited value as a screening tool for high retrograde flow in a clinical setting, as only ∼23% of patients can be spared 4D flow MRI, which remains indispensable for the exact assessment of individual embolization pathways from plaques of the DAo in-vivo.
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Affiliation(s)
- Thomas Wehrum
- Department of Neurology, University Medical Center Freiburg, Freiburg, Germany
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Wehrum T, Kams M, Strecker C, Dragonu I, Günther F, Geibel A, Drexl J, Hennemuth A, Schumacher M, Jung B, Harloff A. Prevalence of Potential Retrograde Embolization Pathways in the Proximal Descending Aorta in Stroke Patients and Controls. Cerebrovasc Dis 2014; 38:410-7. [DOI: 10.1159/000369001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/13/2014] [Indexed: 11/19/2022] Open
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