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2,578 results on '"Nikolaou Konstantin"'

1. Longitudinal monitoring of Apparent Diffusion Coefficient (ADC) in patients with prostate cancer undergoing MR-guided radiotherapy on an MR-Linac at 1.5 T: a prospective feasibility study

Author

Almansour Haidara, Schick Fritz, Nachbar Marcel, Afat Saif, Fritz Victor, Thorwarth Daniela, Zips Daniel, Bertram Felix, Müller Arndt-Christian, Nikolaou Konstantin, Othman Ahmed E, and Wegener Daniel

Subjects
prostate carcinoma, mri, adaptive radiotherapy, image guidance, mr-linac, adc, Medical physics. Medical radiology. Nuclear medicine, R895-920
Abstract

Hybrid MRI linear accelerators (MR-Linac) might enable individualized online adaptation of radiotherapy using quantitative MRI sequences as diffusion-weighted imaging (DWI). The purpose of this study was to investigate the dynamics of lesion apparent diffusion coefficient (ADC) in patients with prostate cancer undergoing MR-guided radiation therapy (MRgRT) on a 1.5T MR-Linac. The ADC values at a diagnostic 3T MRI scanner were used as the reference standard.

Published
2023
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2. Collective variables of neural networks: empirical time evolution and scaling laws

Author

Tovey, Samuel, Krippendorf, Sven, Spannowsky, Michael, Nikolaou, Konstantin, and Holm, Christian

Subjects
Computer Science - Machine Learning, Physics - Computational Physics
Abstract

This work presents a novel means for understanding learning dynamics and scaling relations in neural networks. We show that certain measures on the spectrum of the empirical neural tangent kernel, specifically entropy and trace, yield insight into the representations learned by a neural network and how these can be improved through architecture scaling. These results are demonstrated first on test cases before being shown on more complex networks, including transformers, auto-encoders, graph neural networks, and reinforcement learning studies. In testing on a wide range of architectures, we highlight the universal nature of training dynamics and further discuss how it can be used to understand the mechanisms behind learning in neural networks. We identify two such dominant mechanisms present throughout machine learning training. The first, information compression, is seen through a reduction in the entropy of the NTK spectrum during training, and occurs predominantly in small neural networks. The second, coined structure formation, is seen through an increasing entropy and thus, the creation of structure in the neural network representations beyond the prior established by the network at initialization. Due to the ubiquity of the latter in deep neural network architectures and its flexibility in the creation of feature-rich representations, we argue that this form of evolution of the network's entropy be considered the onset of a deep learning regime., Comment: 11 pages, 3 figures

Published
2024

4. Results from the autoPET challenge on fully automated lesion segmentation in oncologic PET/CT imaging

Author

Gatidis, Sergios, Früh, Marcel, Fabritius, Matthias P., Gu, Sijing, Nikolaou, Konstantin, Fougère, Christian La, Ye, Jin, He, Junjun, Peng, Yige, Bi, Lei, Ma, Jun, Wang, Bo, Zhang, Jia, Huang, Yukun, Heiliger, Lars, Marinov, Zdravko, Stiefelhagen, Rainer, Egger, Jan, Kleesiek, Jens, Sibille, Ludovic, Xiang, Lei, Bendazzoli, Simone, Astaraki, Mehdi, Ingrisch, Michael, Cyran, Clemens C., and Küstner, Thomas

Published
2024
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6. SwarmRL: Building the Future of Smart Active Systems

Author

Tovey, Samuel, Lohrmann, Christoph, Merkt, Tobias, Zimmer, David, Nikolaou, Konstantin, Koppenhöfer, Simon, Bushmakina, Anna, Scheunemann, Jonas, and Holm, Christian

Subjects
Computer Science - Robotics, Condensed Matter - Soft Condensed Matter, Computer Science - Artificial Intelligence, Computer Science - Multiagent Systems, Physics - Biological Physics
Abstract

This work introduces SwarmRL, a Python package designed to study intelligent active particles. SwarmRL provides an easy-to-use interface for developing models to control microscopic colloids using classical control and deep reinforcement learning approaches. These models may be deployed in simulations or real-world environments under a common framework. We explain the structure of the software and its key features and demonstrate how it can be used to accelerate research. With SwarmRL, we aim to streamline research into micro-robotic control while bridging the gap between experimental and simulation-driven sciences. SwarmRL is available open-source on GitHub at https://github.com/SwarmRL/SwarmRL., Comment: 16 pages, 3 figures

Published
2024

10. Competence of radiologists in cardiac CT and MR imaging in Europe: insights from the ESCR Registry

Author

Catapano, Federica, Moser, Lukas Jakob, Francone, Marco, Catalano, Carlo, Vliegenthart, Rozemarijn, Budde, Ricardo P. J., Salgado, Rodrigo, Hrabak Paar, Maja, Pirnat, Maja, Loewe, Christian, Nikolaou, Konstantin, Williams, Michelle C., Muscogiuri, Giuseppe, Natale, Luigi, Lehmkuhl, Lukas, Sieren, Malte Maria, Gutberlet, Matthias, and Alkadhi, Hatem

Published
2024
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11. Feasibility, classification and potential clinical impact of non-invasive delineation of abdominal lymphatic vessels in patients following TCPC with T2 weighted MRI

Author

Hanser, Anja, Hofbeck, Michael, Hofmeister, Melanie, Martirosian, Petros, Hornung, Andreas, Esser, Michael, Schick, Fritz, Küstner, Thomas, Kaulitz, Renate, Michel, Jörg, Nikolaou, Konstantin, Schäfer, Jürgen, Schlensak, Christian, Baden, Winfried, Nordmeyer, Johannes, and Sieverding, Ludger

Published
2024
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12. Correction: Standards for conducting and reporting consensus and recommendation documents: European Society of Cardiovascular Radiology policy from the Guidelines Committee

Author

Lupi, Amalia, Suchá, Dominika, Cundari, Giulia, Fink, Nicola, Alkadhi, Hatem, Budde, Ricardo P. J., Caobelli, Federico, De Cecco, Carlo N., Galea, Nicola, Hrabak-Paar, Maja, Loewe, Christian, Luetkens, Julian A., Muscogiuri, Giuseppe, Natale, Luigi, Nikolaou, Konstantin, Pirnat, Maja, Saba, Luca, Salgado, Rodrigo, Williams, Michelle C., Wintersperger, Bernd J., Vliegenthart, Rozemarijn, Francone, Marco, and Pepe, Alessia

Published
2024
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13. Standards for conducting and reporting consensus and recommendation documents: European Society of Cardiovascular Radiology policy from the Guidelines Committee

Author

Lupi, Amalia, Suchá, Dominika, Cundari, Giulia, Fink, Nicola, Alkadhi, Hatem, Budde, Ricardo P. J., Caobelli, Federico, De Cecco, Carlo N., Galea, Nicola, Hrabak-Paar, Maja, Loewe, Christian, Luetkens, Julian, Muscogiuri, Giuseppe, Natale, Luigi, Nikolaou, Konstantin, Pirnat, Maja, Saba, Luca, Salgado, Rodrigo, Williams, Michelle C., Wintersperger, Bernd J., Vliegenthart, Rozemarijn, Francone, Marco, and Pepe, Alessia

Published
2024
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14. Towards a Phenomenological Understanding of Neural Networks: Data

Author

Tovey, Samuel, Krippendorf, Sven, Nikolaou, Konstantin, and Holm, Christian

Subjects
Computer Science - Machine Learning, Physics - Computational Physics
Abstract

A theory of neural networks (NNs) built upon collective variables would provide scientists with the tools to better understand the learning process at every stage. In this work, we introduce two such variables, the entropy and the trace of the empirical neural tangent kernel (NTK) built on the training data passed to the model. We empirically analyze the NN performance in the context of these variables and find that there exists correlation between the starting entropy, the trace of the NTK, and the generalization of the model computed after training is complete. This framework is then applied to the problem of optimal data selection for the training of NNs. To this end, random network distillation (RND) is used as a means of selecting training data which is then compared with random selection of data. It is shown that not only does RND select data-sets capable of outperforming random selection, but that the collective variables associated with the RND data-sets are larger than those of the randomly selected sets. The results of this investigation provide a stable ground from which the selection of data for NN training can be driven by this phenomenological framework., Comment: 13 pages, 7 figures

Published
2023

15. Characterization of harmonic modes and parasitic resonances in multi-mode superconducting coplanar resonators

Author

Beydeda, Cenk, Nikolaou, Konstantin, Tochtermann, Marius, Ebensperger, Nikolaj G., Untereiner, Gabriele, Farag, Ahmed, Karl, Philipp, Ubl, Monika, Giessen, Harald, Dressel, Martin, and Scheffler, Marc

Subjects
Condensed Matter - Superconductivity
Abstract

Planar superconducting microwave transmission line resonators can be operated at multiple harmonic resonance frequencies. This allows covering wide spectral regimes with high sensitivity, as it is desired e.g. for cryogenic microwave spectroscopy. A common complication of such experiments is the presence of undesired 'spurious' additional resonances, which are due to standing waves within the resonator substrate or housing box. Identifying the nature of individual resonances ('designed' vs. 'spurious') can become challenging for higher frequencies or if elements with unknown material properties are included, as is common for microwave spectroscopy. Here we discuss various experimental strategies to distinguish designed and spurious modes in coplanar superconducting resonators that are operated in a broad frequency range up to 20 GHz. These strategies include tracking resonance evolution as a function of temperature, magnetic field, and microwave power. We also demonstrate that local modification of the resonator, by applying minute amounts of dielectric or ESR-active materials, lead to characteristic signatures in the various resonance modes, depending on the local strength of the electric or magnetic microwave fields.

Published
2023
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22. Computed tomography angiography versus Agatston score for diagnosis of coronary artery disease in patients with stable chest pain: individual patient data meta-analysis of the international COME-CCT Consortium

Author

Wieske, Viktoria, Walther, Mario, Dubourg, Benjamin, Alkadhi, Hatem, Nørgaard, Bjarne L, Meijs, Matthijs FL, Diederichsen, Axel CP, Wan, Yung-Liang, Mickley, Hans, Nikolaou, Konstantin, Shabestari, Abbas A, Halvorsen, Bjørn A, Martuscelli, Eugenio, Sun, Kai, Herzog, Bernhard A, Marcus, Roy P, Leschka, Sebastian, Garcia, Mario J, Ovrehus, Kristian A, Knuuti, Juhani, Mendoza-Rodriguez, Vladymir, Bettencourt, Nuno, Muraglia, Simone, Buechel, Ronny R, Kaufmann, Philipp A, Zimmermann, Elke, Tardif, Jean-Claude, Budoff, Matthew J, Schlattmann, Peter, and Dewey, Marc

Subjects
Biomedical and Clinical Sciences, Cardiovascular Medicine and Haematology, Clinical Sciences, Heart Disease - Coronary Heart Disease, Atherosclerosis, Cardiovascular, Heart Disease, Biomedical Imaging, Clinical Research, 4.2 Evaluation of markers and technologies, Detection, screening and diagnosis, Calcium, Chest Pain, Computed Tomography Angiography, Coronary Angiography, Coronary Artery Disease, Coronary Stenosis, Humans, Predictive Value of Tests, Tomography, X-Ray Computed, Computed tomography angiography, Coronary angiography, Coronary artery disease, COME-CCT Consortium, Nuclear Medicine & Medical Imaging, Clinical sciences
Abstract

ObjectivesThere is conflicting evidence about the comparative diagnostic accuracy of the Agatston score versus computed tomography angiography (CTA) in patients with suspected obstructive coronary artery disease (CAD).PurposeTo determine whether CTA is superior to the Agatston score in the diagnosis of CAD.MethodsIn total 2452 patients with stable chest pain and a clinical indication for invasive coronary angiography (ICA) for suspected CAD were included by the Collaborative Meta-analysis of Cardiac CT (COME-CCT) Consortium. An Agatston score of > 400 was considered positive, and obstructive CAD defined as at least 50% coronary diameter stenosis on ICA was used as the reference standard.ResultsObstructive CAD was diagnosed in 44.9% of patients (1100/2452). The median Agatston score was 74. Diagnostic accuracy of CTA for the detection of obstructive CAD (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) was significantly higher than that of the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p < 0.001). Among patients with an Agatston score of zero, 17% (101/600) had obstructive CAD. Diagnostic accuracy of CTA was not significantly different in patients with low to intermediate (1 to < 100, 100-400) versus moderate to high Agatston scores (401-1000, > 1000).ConclusionsResults in our international cohort show CTA to have significantly higher diagnostic accuracy than the Agatston score in patients with stable chest pain, suspected CAD, and a clinical indication for ICA. Diagnostic performance of CTA is not affected by a higher Agatston score while an Agatston score of zero does not reliably exclude obstructive CAD.Key points• CTA showed significantly higher diagnostic accuracy (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) for diagnosis of coronary artery disease when compared to the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p < 0.001). • Diagnostic performance of CTA was not affected by increased amount of calcium and was not significantly different in patients with low to intermediate (1 to 1000). • Seventeen percent of patients with an Agatston score of zero showed obstructive coronary artery disease by invasive angiography showing absence of coronary artery calcium cannot reliably exclude coronary artery disease.

Published
2022

36. Fully Automated and Standardized Segmentation of Adipose Tissue Compartments by Deep Learning in Three-dimensional Whole-body MRI of Epidemiological Cohort Studies

Author

Küstner, Thomas, Hepp, Tobias, Fischer, Marc, Schwartz, Martin, Fritsche, Andreas, Häring, Hans-Ulrich, Nikolaou, Konstantin, Bamberg, Fabian, Yang, Bin, Schick, Fritz, Gatidis, Sergios, and Machann, Jürgen

Subjects
Computer Science - Computer Vision and Pattern Recognition, Electrical Engineering and Systems Science - Image and Video Processing, Physics - Medical Physics
Abstract

Purpose: To enable fast and reliable assessment of subcutaneous and visceral adipose tissue compartments derived from whole-body MRI. Methods: Quantification and localization of different adipose tissue compartments from whole-body MR images is of high interest to examine metabolic conditions. For correct identification and phenotyping of individuals at increased risk for metabolic diseases, a reliable automatic segmentation of adipose tissue into subcutaneous and visceral adipose tissue is required. In this work we propose a 3D convolutional neural network (DCNet) to provide a robust and objective segmentation. In this retrospective study, we collected 1000 cases (66$\pm$ 13 years; 523 women) from the Tuebingen Family Study and from the German Center for Diabetes research (TUEF/DZD), as well as 300 cases (53$\pm$ 11 years; 152 women) from the German National Cohort (NAKO) database for model training, validation, and testing with a transfer learning between the cohorts. These datasets had variable imaging sequences, imaging contrasts, receiver coil arrangements, scanners and imaging field strengths. The proposed DCNet was compared against a comparable 3D UNet segmentation in terms of sensitivity, specificity, precision, accuracy, and Dice overlap. Results: Fast (5-7seconds) and reliable adipose tissue segmentation can be obtained with high Dice overlap (0.94), sensitivity (96.6%), specificity (95.1%), precision (92.1%) and accuracy (98.4%) from 3D whole-body MR datasets (field of view coverage 450x450x2000mm${}^3$). Segmentation masks and adipose tissue profiles are automatically reported back to the referring physician. Conclusion: Automatic adipose tissue segmentation is feasible in 3D whole-body MR data sets and is generalizable to different epidemiological cohort studies with the proposed DCNet., Comment: This manuscript has been accepted for publication in Radiology: Artificial Intelligence (https://pubs.rsna.org/journal/ai), which is published by the Radiological Society of North America (RSNA)

Published
2020

37. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT)

Author

Schuetz Georg M, Schlattmann Peter, Achenbach Stephan, Budoff Matthew, Garcia Mario J, Roehle Robert, Pontone Gianluca, Meijboom Willem Bob, Andreini Daniele, Alkadhi Hatem, Honoris Lily, Bettencourt Nuno, Hausleiter Jörg, Leschka Sebastian, Gerber Bernhard L, Meijs Matthijs FL, Shabestari Abbas Arjmand, Sato Akira, Zimmermann Elke, Schoepf Uwe J, Diederichsen Axel, Halon David A, Mendoza-Rodriguez Vladimir, Hamdan Ashraf, Nørgaard Bjarne L, Brodoefel Harald, Øvrehus Kristian A, Jenkins Shona MM, Halvorsen Bjørn A, Rixe Johannes, Sheikh Mehraj, Langer Christoph, Martuscelli Eugenio, Romagnoli Andrea, Scholte Arthur JHA, Marcus Roy P, Ulimoen Geir R, Nieman Koen, Mickley Hans, Nikolaou Konstantin, Tardif Jean-Claude, Johnson Thorsten RC, Muraglia Simone, Chow Benjamin JW, Maintz David, Laule Michael, and Dewey Marc

Subjects
Collaborative meta-analysis on cardiac CT, CoMe-CCT, Coronary CT angiography, Individual patient data meta-analysis, IPD, Positive and negative predictive value, Pretest likelihood, Sensitivity and specificity, Study protocol, Medicine
Abstract

Abstract Background Coronary computed tomography angiography has become the foremost noninvasive imaging modality of the coronary arteries and is used as an alternative to the reference standard, conventional coronary angiography, for direct visualization and detection of coronary artery stenoses in patients with suspected coronary artery disease. Nevertheless, there is considerable debate regarding the optimal target population to maximize clinical performance and patient benefit. The most obvious indication for noninvasive coronary computed tomography angiography in patients with suspected coronary artery disease would be to reliably exclude significant stenosis and, thus, avoid unnecessary invasive conventional coronary angiography. To do this, a test should have, at clinically appropriate pretest likelihoods, minimal false-negative outcomes resulting in a high negative predictive value. However, little is known about the influence of patient characteristics on the clinical predictive values of coronary computed tomography angiography. Previous regular systematic reviews and meta-analyses had to rely on limited summary patient cohort data offered by primary studies. Performing an individual patient data meta-analysis will enable a much more detailed and powerful analysis and thus increase representativeness and generalizability of the results. The individual patient data meta-analysis is registered with the PROSPERO database (CoMe-CCT, CRD42012002780). Methods/Design The analysis will include individual patient data from published and unpublished prospective diagnostic accuracy studies comparing coronary computed tomography angiography with conventional coronary angiography. These studies will be identified performing a systematic search in several electronic databases. Corresponding authors will be contacted and asked to provide obligatory and additional data. Risk factors, previous test results and symptoms of individual patients will be used to estimate the pretest likelihood of coronary artery disease. A bivariate random-effects model will be used to calculate pooled mean negative and positive predictive values as well as sensitivity and specificity. The primary outcome of interest will be positive and negative predictive values of coronary computed tomography angiography for the presence of coronary artery disease as a function of pretest likelihood of coronary artery disease, analyzed by meta-regression. As a secondary endpoint, factors that may influence the diagnostic performance and clinical value of computed tomography, such as heart rate and body mass index of patients, number of detector rows, and administration of beta blockade and nitroglycerin, will be investigated by integrating them as further covariates into the bivariate random-effects model. Discussion This collaborative individual patient data meta-analysis should provide answers to the pivotal question of which patients benefit most from noninvasive coronary computed tomography angiography and thus help to adequately select the right patients for this test.

Published
2013
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39. Generative Pre-trained Transformer 4 analysis of cardiovascular magnetic resonance reports in suspected myocarditis: A multicenter study

Author

Kaya, Kenan, Gietzen, Carsten, Hahnfeldt, Robert, Zoubi, Maher, Emrich, Tilman, Halfmann, Moritz C., Sieren, Malte Maria, Elser, Yannic, Krumm, Patrick, Brendel, Jan M., Nikolaou, Konstantin, Haag, Nina, Borggrefe, Jan, Krüchten, Ricarda von, Müller-Peltzer, Katharina, Ehrengut, Constantin, Denecke, Timm, Hagendorff, Andreas, Goertz, Lukas, Gertz, Roman J., Bunck, Alexander Christian, Maintz, David, Persigehl, Thorsten, Lennartz, Simon, Luetkens, Julian A., Jaiswal, Astha, Iuga, Andra Iza, Pennig, Lenhard, and Kottlors, Jonathan

Published
2024
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40. Characteristics of carotid atherosclerotic plaques of chronic lipid apheresis patients as assessed by In Vivo High-Resolution CMR - a comparative analysis

Author

Grimm Jochen M, Nikolaou Konstantin, Schindler Andreas, Hettich Reinhard, Heigl Franz, Cyran Clemens C, Schwarz Florian, Klingel Reinhard, Karpinska Anna, Yuan Chun, Dichgans Martin, Reiser Maximilian F, and Saam Tobias

Subjects
Atherosclerosis, Lipid apheresis, Cardiovascular MR, Plaque imaging, Stroke, Cardiovascular disease, Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Background Components of carotid atherosclerotic plaques can reliably be identified and quantified using high resolution in vivo 3-Tesla CMR. It is suspected that lipid apheresis therapy in addition to lowering serum lipid levels also has an influence on development and progression of atherosclerotic plaques. The purpose of this study was to evaluate the influence of chronic lipid apheresis (LA) on the composition of atherosclerotic carotid plaques. Methods 32 arteries of 16 patients during chronic LA-therapy with carotid plaques and stenosis of 1–80% were matched according to degree of stenosis with 32 patients, who had recently suffered an ischemic stroke. Of these patients only the asymptomatic carotid artery was analyzed. All patients underwent black-blood 3 T CMR of the carotids using parallel imaging and dedicated surface coils. Cardiovascular risk factors were recorded. Morphology and composition of carotid plaques were evaluated. For statistical evaluation Fisher’s Exact and unpaired t-test were used. A p-value Results Patients in the LA-group were younger (63.5 vs. 73.9. years, p2, p Conclusion Results of this study suggest that, despite a severer risk profile for cardiovascular complications in LA-patients, chronic LA is associated with significantly lower lipid content in carotid plaques compared to plaques of patients without LA with similar degrees of stenosis, which is characteristic of clinically stable plaques.

Published
2012
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41. Age determination of vessel wall hematoma in spontaneous cervical artery dissection: A multi-sequence 3T Cardiovascular Magnetic resonance study

Author

Habs Maximilian, Pfefferkorn Thomas, Cyran Clemens C, Grimm Jochen, Rominger Axel, Hacker Marcus, Opherk Christian, Reiser Maximilian F, Nikolaou Konstantin, and Saam Tobias

Subjects
CMR, internal carotid artery dissection, vertebral artery dissection, hematoma, stroke, Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Background Previously proposed classifications for carotid plaque and cerebral parenchymal hemorrhages are used to estimate the age of hematoma according to its signal intensities on T1w and T2w MR images. Using these classifications, we systematically investigated the value of cardiovascular magnetic resonance (CMR) in determining the age of vessel wall hematoma (VWH) in patients with spontaneous cervical artery dissection (sCAD). Methods 35 consecutive patients (mean age 43.6 ± 9.8 years) with sCAD received a cervical multi-sequence 3T CMR with fat-saturated black-blood T1w-, T2w- and TOF images. Age of sCAD was defined as time between onset of symptoms (stroke, TIA or Horner's syndrome) and the CMR scan. VWH were categorized into hyperacute, acute, early subacute, late subacute and chronic based on their signal intensities on T1w- and T2w images. Results The mean age of sCAD was 2.0, 5.8, 15.7 and 58.7 days in patients with acute, early subacute, late subacute and chronic VWH as classified by CMR (p < 0.001 for trend). Agreement was moderate between VWH types in our study and the previously proposed time scheme of signal evolution for cerebral hemorrhage, Cohen's kappa 0.43 (p < 0.001). There was a strong agreement of CMR VWH classification compared to the time scheme which was proposed for carotid intraplaque hematomas with Cohen's kappa of 0.74 (p < 0.001). Conclusions Signal intensities of VWH in sCAD vary over time and multi-sequence CMR can help to determine the age of an arterial dissection. Furthermore, findings of this study suggest that the time course of carotid hematomas differs from that of cerebral hematomas.

Published
2011
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42. High resolution carotid black-blood 3T MR with parallel imaging and dedicated 4-channel surface coils

Author

Frey Ute, Clevert Dirk A, Dietrich Olaf, Meimarakis Georgios, Bochmann Katja, Cyran Clemens C, Raya Jose G, Saam Tobias, Yuan Chun, Hatsukami Thomas S, Werf Abe, Reiser Maximilian F, and Nikolaou Konstantin

Subjects
Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Background Most of the carotid plaque MR studies have been performed using black-blood protocols at 1.5 T without parallel imaging techniques. The purpose of this study was to evaluate a multi-sequence, black-blood MR protocol using parallel imaging and a dedicated 4-channel surface coil for vessel wall imaging of the carotid arteries at 3 T. Materials and methods 14 healthy volunteers and 14 patients with intimal thickening as proven by duplex ultrasound had their carotid arteries imaged at 3 T using a multi-sequence protocol (time-of-flight MR angiography, pre-contrast T1w-, PDw- and T2w sequences in the volunteers, additional post-contrast T1w- and dynamic contrast enhanced sequences in patients). To assess intrascan reproducibility, 10 volunteers were scanned twice within 2 weeks. Results Intrascan reproducibility for quantitative measurements of lumen, wall and outer wall areas was excellent with Intraclass Correlation Coefficients >0.98 and measurement errors of 1.5%, 4.5% and 1.9%, respectively. Patients had larger wall areas than volunteers in both common carotid and internal carotid arteries and smaller lumen areas in internal carotid arteries (p < 0.001). Positive correlations were found between wall area and cardiovascular risk factors such as age, hypertension, coronary heart disease and hypercholesterolemia (Spearman's r = 0.45-0.76, p < 0.05). No significant correlations were found between wall area and body mass index, gender, diabetes or a family history of cardiovascular disease. Conclusion The findings of this study indicate that high resolution carotid black-blood 3 T MR with parallel imaging is a fast, reproducible and robust method to assess carotid atherosclerotic plaque in vivo and this method is ready to be used in clinical practice.

Published
2009
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46. Uterine allograft removal by total laparoscopic hysterectomy after successful cesarean delivery in a living-donor uterus recipient with uterovaginal agenesis (MRKHS)

Author

Brucker, Sara Yvonne, Krämer, Bernhard, Abele, Harald, Henes, Melanie, Hoopmann, Markus, Schöller, Dorit, Königsrainer, Alfred, Bösmüller, Hans, Nikolaou, Konstantin, Krumm, Patrick, Rosenberger, Peter, Heim, Eckhard, Amend, Bastian, Rausch, Steffen, Althaus, Karina, Bakchoul, Tamam, Guthoff, Martina, Heyne, Nils, Nadalin, Silvio, and Rall, Kristin Katharina

Published
2023
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47. State-of-the-art CT and MR imaging and assessment of atherosclerotic carotid artery disease: standardization of scanning protocols and measurements—a consensus document by the European Society of Cardiovascular Radiology (ESCR)

Author

Saba, Luca, Loewe, Christian, Weikert, Thomas, Williams, Michelle C., Galea, Nicola, Budde, Ricardo P. J., Vliegenthart, Rozemarijn, Velthuis, Birgitta K., Francone, Marco, Bremerich, Jens, Natale, Luigi, Nikolaou, Konstantin, Dacher, Jean-Nicolas, Peebles, Charles, Caobelli, Federico, Redheuil, Alban, Dewey, Marc, Kreitner, Karl-Friedrich, and Salgado, Rodrigo

Published
2023
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48. State-of-the-art CT and MR imaging and assessment of atherosclerotic carotid artery disease: the reporting—a consensus document by the European Society of Cardiovascular Radiology (ESCR)

Author

Saba, Luca, Loewe, Christian, Weikert, Thomas, Williams, Michelle C., Galea, Nicola, Budde, Ricardo P. J., Vliegenthart, Rozemarijn, Velthuis, Birgitta K., Francone, Marco, Bremerich, Jens, Natale, Luigi, Nikolaou, Konstantin, Dacher, Jean-Nicolas, Peebles, Charles, Caobelli, Federico, Redheuil, Alban, Dewey, Marc, Kreitner, Karl-Friedrich, and Salgado, Rodrigo

Published
2023
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