14 results on '"Christian Bunck A"'
Search Results
2. Photon counting computed tomography of in-stent-stenosis in a phantom: Optimal virtual monoenergetic imaging in ultra high resolution
- Author
-
Arwed Elias Michael, Denise Schoenbeck, Matthias Michael Woeltjen, Jan Boriesosdick, Julius Henning Niehoff, Alexey Surov, Jan Borggrefe, Bernhard Schmidt, Christoph Panknin, Tilman Hickethier, David Maintz, Alexander Christian Bunck, Roman Johannes Gertz, and Jan Robert Kroeger
- Subjects
Computed tomography ,Photon counting computed tomography ,Photon counting detector ,In-stent stenosis ,Stent imaging ,Virtual monoenergetic image ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
1 Abstract: Rationale and objectives: Coronary computed tomography angiography (CCTA) is becoming increasingly important for the diagnostic workup of coronary artery disease, nevertheless, imaging of in-stent stenosis remains challenging. For the first time, spectral imaging in Ultra High Resolution (UHR) is now possible in clinically available photon counting CT. The aim of this work is to determine the optimal virtual monoenergetic image (VMI) for imaging in-stent stenoses in cardiac stents. Materials and methods: 6 stents with inserted hypodense stenoses were scanned in an established phantom in UHR mode. Images were reconstructed with 3 different kernels for spectral data (Qr56, Qr64, Qr72) with varying levels of sharpness. Based on region of interest (ROI) measurements image quality parameters including contrast-to-noise ratio (CNR) were analyzed for all available VMI (40 keV–190 keV). Finally, based on quantitative results and VMI used in clinical routine, a set of VMI was included in a qualitative reading. Results: CNR showed significant variations across different keV levels (p
- Published
- 2024
- Full Text
- View/download PDF
3. Generative Pre-trained Transformer 4 analysis of cardiovascular magnetic resonance reports in suspected myocarditis: A multicenter study
- Author
-
Kenan Kaya, Carsten Gietzen, Robert Hahnfeldt, Maher Zoubi, Tilman Emrich, Moritz C. Halfmann, Malte Maria Sieren, Yannic Elser, Patrick Krumm, Jan M. Brendel, Konstantin Nikolaou, Nina Haag, Jan Borggrefe, Ricarda von Krüchten, Katharina Müller-Peltzer, Constantin Ehrengut, Timm Denecke, Andreas Hagendorff, Lukas Goertz, Roman J. Gertz, Alexander Christian Bunck, David Maintz, Thorsten Persigehl, Simon Lennartz, Julian A. Luetkens, Astha Jaiswal, Andra Iza Iuga, Lenhard Pennig, and Jonathan Kottlors
- Subjects
Cardiovascular magnetic resonance ,Generative Pre-trained Transformer 4 ,Artificial intelligence ,Large language models ,Myocarditis ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
ABSTRACT: Background: Diagnosing myocarditis relies on multimodal data, including cardiovascular magnetic resonance (CMR), clinical symptoms, and blood values. The correct interpretation and integration of CMR findings require radiological expertise and knowledge. We aimed to investigate the performance of Generative Pre-trained Transformer 4 (GPT-4), a large language model, for report-based medical decision-making in the context of cardiac MRI for suspected myocarditis. Methods: This retrospective study includes CMR reports from 396 patients with suspected myocarditis and eight centers, respectively. CMR reports and patient data including blood values, age, and further clinical information were provided to GPT-4 and radiologists with 1 (resident 1), 2 (resident 2), and 4 years (resident 3) of experience in CMR and knowledge of the 2018 Lake Louise Criteria. The final impression of the report regarding the radiological assessment of whether myocarditis is present or not was not provided. The performance of Generative pre-trained transformer 4 (GPT-4) and the human readers were compared to a consensus reading (two board-certified radiologists with 8 and 10 years of experience in CMR). Sensitivity, specificity, and accuracy were calculated. Results: GPT-4 yielded an accuracy of 83%, sensitivity of 90%, and specificity of 78%, which was comparable to the physician with 1 year of experience (R1: 86%, 90%, 84%, p = 0.14) and lower than that of more experienced physicians (R2: 89%, 86%, 91%, p = 0.007 and R3: 91%, 85%, 96%, p
- Published
- 2024
- Full Text
- View/download PDF
4. Compressed SENSE accelerated 3D single-breath-hold late gadolinium enhancement cardiovascular magnetic resonance with isotropic resolution: clinical evaluation
- Author
-
Roman Johannes Gertz, Anton Wagner, Marcel Sokolowski, Simon Lennartz, Carsten Gietzen, Jan-Peter Grunz, Lukas Goertz, Kenan Kaya, Henrik ten Freyhaus, Thorsten Persigehl, Alexander Christian Bunck, Jonas Doerner, Claas Philip Naehle, David Maintz, Kilian Weiss, Christoph Katemann, and Lenhard Pennig
- Subjects
cardiovascular magnetic resonance ,late gadolinium enhancement ,isotropic resolution ,ischemic cardiomyopathy ,non-ischemic cardiomyopathy ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
AimThe purpose of this study was to investigate the clinical application of Compressed SENSE accelerated single-breath-hold LGE with 3D isotropic resolution compared to conventional LGE imaging acquired in multiple breath-holds.Material & MethodsThis was a retrospective, single-center study including 105 examinations of 101 patients (48.2 ± 16.8 years, 47 females). All patients underwent conventional breath-hold and 3D single-breath-hold (0.96 × 0.96 × 1.1 mm3 reconstructed voxel size, Compressed SENSE factor 6.5) LGE sequences at 1.5 T in clinical routine for the evaluation of ischemic or non-ischemic cardiomyopathies. Two radiologists independently evaluated the left ventricle (LV) for the presence of hyperenhancing lesions in each sequence, including localization and transmural extent, while assessing their scar edge sharpness (SES). Confidence of LGE assessment, image quality (IQ), and artifacts were also rated. The impact of LV ejection fraction (LVEF), heart rate, body mass index (BMI), and gender as possible confounders on IQ, artifacts, and confidence of LGE assessment was evaluated employing ordinal logistic regression analysis.ResultsUsing 3D single-breath-hold LGE readers detected more hyperenhancing lesions compared to conventional breath-hold LGE (n = 246 vs. n = 216 of 1,785 analyzed segments, 13.8% vs. 12.1%; p
- Published
- 2023
- Full Text
- View/download PDF
5. Pseudoaneurysm of an intercostal artery: endovascular treatment with PK papyrus coronary stent to prevent spinal ischemia
- Author
-
Julius Niehoff, Alexander Christian Bunck, David Maintz, and Jan Robert Kroeger
- Subjects
Endovascular treatment ,Acute bleeding ,Pseudoaneurysm ,Stentgraft ,Spinal ischemia ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Endovascular treatment can be a fast and safe option in the case of acute, internal bleeding – but it requires special knowledge and technical skills. Interventionalists must consider the anatomy and potential complications. As in this case report, the anterior spinal artery, for example, can be a crucial vessel that must always be considered when embolizing intercostal or lumbar arteries. The risk of spinal ischemia has to be taken into account and should be minimized by choosing the appropriate treatment option. Case presentation We report about a 77 year old, male patient with upper gastrointestinal bleeding after esophagectomy and gastric conduit reconstruction. A CT scan identified a pseudoaneurysm of an intercostal artery penetrating the gastric conduit as the bleeding source. In the DSA, a direct connection between the intercostal artery and the anterior spinal artery appeared to be likely. Due to the associated risk of spinal ischemia, an embolization of the intercostal artery was not an option. We decided to implant a stentgraft that would stop the perfusion of the pseudoaneurysm, but preserve the perfusion of the intercostal artery. Due to the small diameter of the vessel, we could not implant our commonly used stentgrafts in this case. Therefore, we chose an uncommon solution and used a stentgraft that is designed primarily for coronary arteries. Conclusions Whenever intercostal or lumbar arteries need to be embolized, a possible connection to the anterior spinal artery must be considered and interventionalists have to be aware of possible ischemic complications. In this case, a stentgraft designed primarily for coronary arteries offered a good endovascular treatment option for the pseudoaneurysm of an intercostal artery. The risk of spinal ischemia could be minimized by using this stentgraft.
- Published
- 2021
- Full Text
- View/download PDF
6. Clinical application of free-breathing 3D whole heart late gadolinium enhancement cardiovascular magnetic resonance with high isotropic spatial resolution using Compressed SENSE
- Author
-
Lenhard Pennig, Simon Lennartz, Anton Wagner, Marcel Sokolowski, Matej Gajzler, Svenja Ney, Kai Roman Laukamp, Thorsten Persigehl, Alexander Christian Bunck, David Maintz, Kilian Weiss, Claas Philip Naehle, and Jonas Doerner
- Subjects
Late gadolinium enhancement ,Cardiovascular magnetic resonance ,Cardiomyopathy ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) represents the gold standard for assessment of myocardial viability. The purpose of this study was to investigate the clinical potential of Compressed SENSE (factor 5) accelerated free-breathing three-dimensional (3D) whole heart LGE with high isotropic spatial resolution (1.4 mm3 acquired voxel size) compared to standard breath-hold LGE imaging. Methods This was a retrospective, single-center study of 70 consecutive patients (45.8 ± 18.1 years, 27 females; February–November 2019), who were referred for assessment of left ventricular myocardial viability and received free-breathing and breath-hold LGE sequences at 1.5 T in clinical routine. Two radiologists independently evaluated global and segmental LGE in terms of localization and transmural extent. Readers scored scans regarding image quality (IQ), artifacts, and diagnostic confidence (DC) using 5-point scales (1 non-diagnostic—5 excellent/none). Effects of heart rate and body mass index (BMI) on IQ, artifacts, and DC were evaluated with ordinal logistic regression analysis. Results Global LGE (n = 33) was identical for both techniques. Using free-breathing LGE (average scan time: 04:33 ± 01:17 min), readers detected more hyperenhanced lesions (28.2% vs. 23.5%, P
- Published
- 2020
- Full Text
- View/download PDF
7. Spectral Detector CT-Derived Pulmonary Perfusion Maps and Pulmonary Parenchyma Characteristics for the Semiautomated Classification of Pulmonary Hypertension
- Author
-
Roman Johannes Gertz, Felix Gerhardt, Jan Robert Kröger, Rahil Shahzad, Liliana Caldeira, Jonathan Kottlors, Nils Große Hokamp, David Maintz, Stephan Rosenkranz, and Alexander Christian Bunck
- Subjects
spectral detector CT ,dual energy ,pulmonary hypertension ,pulmonary perfusion maps ,virtual non-contrast pulmonary parenchyma characteristics ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
ObjectivesTo evaluate the usefulness of spectral detector CT (SDCT)-derived pulmonary perfusion maps and pulmonary parenchyma characteristics for the semiautomated classification of pulmonary hypertension (PH).MethodsA total of 162 consecutive patients with right heart catheter (RHC)-proven PH of different aetiologies as defined by the current ESC/ERS guidelines who underwent CT pulmonary angiography (CTPA) on SDCT and 20 patients with an invasive rule-out of PH were included in this retrospective study. Semiautomatic lung segmentation into normal and malperfused areas based on iodine density (ID) as well as automatic, virtual non-contrast-based emphysema quantification were performed. Corresponding volumes, histogram features and the ID SkewnessPerfDef-Emphysema-Index (δ-index) accounting for the ratio of ID distribution in malperfused lung areas and the proportion of emphysematous lung parenchyma were computed and compared between groups.ResultsPatients with PH showed a significantly greater extent of malperfused lung areas as well as stronger and more homogenous perfusion defects. In group 3 and 4 patients, ID skewness revealed a significantly more homogenous ID distribution in perfusion defects than in all other subgroups. The δ-index allowed for further subclassification of subgroups 3 and 4 (p < 0.001), identifying patients with chronic thromboembolic PH (CTEPH, subgroup 4) with high accuracy (AUC: 0.92, 95%-CI, 0.85–0.99).ConclusionAbnormal pulmonary perfusion in PH can be detected and quantified by semiautomated SDCT-based pulmonary perfusion maps. ID skewness in malperfused lung areas, and the δ-index allow for a classification of PH subgroups, identifying groups 3 and 4 patients with high accuracy, independent of reader expertise.
- Published
- 2022
- Full Text
- View/download PDF
8. Association between pouch morphology, cardiovascular risk factors and ischemic brain lesions in patients with left-sided septal pouches
- Author
-
Lukas Goertz, Christian Nelles, Lenhard Pennig, Alexander Christian Bunck, Robert Peter Reimer, Philipp Fervers, Christoph Kabbasch, David Maintz, and Erkan Celik
- Subjects
Radiology, Nuclear Medicine and imaging - Published
- 2023
- Full Text
- View/download PDF
9. Correction to: Imaging of the pulmonary vasculature in congenital heart disease without gadolinium contrast: Intraindividual comparison of a novel Compressed SENSE accelerated 3D modified REACT with 4D contrast-enhanced magnetic resonance angiography
- Author
-
Lenhard Pennig, Anton Wagner, Kilian Weiss, Simon Lennartz, Jan-Peter Grunz, David Maintz, Kai Roman Laukamp, Tilman Hickethier, Claas Philip Naehle, Alexander Christian Bunck, and Jonas Doerner
- Subjects
Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
The original publication of this article [1], contained graphical errors in Figs. 1 and 2. This does not impact the display of the mean differences of the Bland-Altman plots. The updated figures (Fig. 1 and Fig. 2) are published in this correction article.
- Published
- 2020
- Full Text
- View/download PDF
10. Imaging of the pulmonary vasculature in congenital heart disease without gadolinium contrast: Intraindividual comparison of a novel Compressed SENSE accelerated 3D modified REACT with 4D contrast-enhanced magnetic resonance angiography
- Author
-
Lenhard Pennig, Anton Wagner, Kilian Weiss, Simon Lennartz, Jan-Peter Grunz, David Maintz, Kai Roman Laukamp, Tilman Hickethier, Claas Philip Naehle, Alexander Christian Bunck, and Jonas Doerner
- Subjects
Magnetic resonance angiography ,4D CE-MRA ,Contrast agent ,Congenital heart disease ,Pulmonary vasculature ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Patients with Congenital heart disease (CHD) require repetitive imaging of the pulmonary vasculature throughout their life. In this study, we compared a novel Compressed SENSE accelerated (factor 9) electrocardiogram (ECG)- and respiratory-triggered 3D modified Relaxation-Enhanced Angiography without Contrast and Triggering (modified REACT-non-contrast-enhanced magnetic resonance angiography (modified REACT-non-CE-MRA)) with standard non-ECG-triggered time-resolved 4D CE-MRA for imaging of the pulmonary arteries and veins in patients with CHD. Methods This retrospective analysis of 25 patients (June 2018–April 2019) with known or suspected CHD was independently conducted by two radiologists executing measurements on modified REACT-non-CE-MRA and 4D CE-MRA on seven dedicated points (inner edge): Main pulmonary artery (MPA), right and left pulmonary artery, right superior and inferior pulmonary vein, left superior (LSPV) and inferior pulmonary vein. Image quality for arteries and veins was evaluated on a four-point scale in consensus. Results Twenty-three of the 25 included patients presented a CHD. There was a high interobserver agreement for both methods of imaging at the pulmonary arteries (ICC ≥ 0.96); at the pulmonary veins, modified REACT-non-CE-MRA showed a slightly higher agreement, pronounced at LSPV (ICC 0.946 vs. 0.895). Measurements in 4D CE-MRA showed higher diameter values compared to modified REACT-non-CE-MRA, at the pulmonary arteries reaching significant difference (e.g. MPA: mean 0.408 mm, p = 0.002). Modified REACT-non-CE-MRA (average acquisition time 07:01 ± 02:44 min) showed significant better image quality than 4D CE-MRA at the pulmonary arteries (3.84 vs. 3.32, p
- Published
- 2020
- Full Text
- View/download PDF
11. Bildgebende Diagnostik bei pulmonaler Hypertonie
- Author
-
Roman Johannes Gertz, Jan Robert Kröger, Stephan Rosenkranz, and Alexander Christian Bunck
- Subjects
General Medicine - Abstract
ZusammenfassungDie pulmonale Hypertonie (PH) ist ein häufiges und komplexes Krankheitsbild. Unabhängig von ihrer Ätiologie geht sie mit einer hohen Morbidität und Mortalität einher. Im multidisziplinären diagnostischen Algorithmus und Management der PH kommt dem Radiologen bei der frühzeitigen Diagnosestellung, der Subklassifikation und der Prognoseabschätzung eine wegweisende Rolle zu.
- Published
- 2023
- Full Text
- View/download PDF
12. Structured Reporting in Cross-Sectional Imaging of the Heart: Reporting Templates for CMR Imaging of Ischemia and Myocardial Viability and for Cardiac CT Imaging of Coronary Heart Disease and TAVI Planning
- Author
-
Martin Soschynski, Alexander Christian Bunck, Meinrad Beer, Steffen Kloempken, Christopher L Schlett, Bettina Baeßler, Jan Robert Kröger, Thorsten Persigehl, Daniel Pinto dos Santos, Michael Steinmetz, Adelheid Niehaus, Fabian Bamberg, Sebastian Ley, Klaus Tiemann, Philipp Beerbaum, Joachim Lotz, David Maintz, Christopher Kloth, Horst Brunner, and Christian O Ritter
- Subjects
Radiology, Nuclear Medicine and imaging - Abstract
Background Structured reporting allows a high grade of standardization and thus a safe and unequivocal report communication. In the past years, the radiological societies have started several initiatives to base radiological reports on structured reporting rather than free text reporting. Methods Upon invitation of the working group for Cardiovascular Imaging of the German Society of Radiology, in 2018 an interdisciplinary group of Radiologists, Cardiologists, Pediatric Cardiologists and Cardiothoracic surgeons -all experts on the field of cardiovascular MR and CT imaging- met for interdisciplinary consensus meetings at the University Hospital Cologne. The aim of these meetings was to develop and consent templates for structured reporting in cardiac MR and CT of various cardiovascular diseases. Results Two templates for structured reporting of CMR in ischemia imaging and vitality imaging and two templates for structured reporting of CT imaging for planning Transcatheter Aortic Valve Implantation (TAVI; pre-TAVI-CT) and coronary CT were discussed, consented and transferred to a HTML 5/IHR MRRT compatible format. The templates were made available for free use on the website www.befundung.drg.de. Conclusion This paper suggests consented templates in German language for the structured reporting of cross-sectional CMR imaging of ischemia and vitality as well as reporting of CT imaging pre-TAVI and coronary CT. The implementation of these templates is aimed at providing a constant level of high reporting quality and increasing the efficiency of report generation as well as a clinically based communication of imaging results. Key points: Zitierweise
- Published
- 2023
- Full Text
- View/download PDF
13. The Aortic Ductus Diverticulum-Innocent Bystander or Potential Source of Thromboembolic Stroke?
- Author
-
Erkan Celik, Lukas Goertz, Christian Nelles, Jochen Hammes, Tobias Achenbach, Christoph Kabbasch, Thorsten Persigehl, David Maintz, and Alexander Christian Bunck
- Subjects
Stroke ,Diverticulum ,Risk Factors ,Humans ,Radiology, Nuclear Medicine and imaging ,Aorta, Thoracic ,Brain Ischemia ,Retrospective Studies - Abstract
Due to reversal blood flow in the diastolic phase, outpouchings at the aortic isthmus may carry the risk of thrombus formation and subsequent thromboembolism. The objective was to evaluate the association between aortic ductus diverticula (ADDs) and ischemic brain alterations in cerebral magnetic resonance imaging.A retrospective analysis of 218 patients who received both a dedicated computed tomography angiography of the thoracic aorta and a brain magnetic resonance imaging was performed. Two radiologists independently reviewed all examinations for the presence of ADD as well as ischemic alterations of the brain. The association between this anatomical variant and ischemic brain alterations was evaluated by univariate and bivariate logistic regression analyses.ADDs were identified/present in 35 of 218 patients (16%). Ischemic brain alterations were found in 57% of patients (20/35) with an ADD and in 42% of the control group (77/183, P = 0.1). The presence of an ADD did not prove to be an independent risk factor for ischemic brain alterations after multivariate adjustment (odds ratio = 1.7, 95% confidence interval = 0.72-3.96, P = 0.225).In the present study, ADDs were not significantly associated with ischemic brain alterations. Therefore, ADDs seem to be an innocent bystander with respect to the pathogenesis of ischemic brain alterations.
- Published
- 2022
14. Quantitative Analysis of Vortical Blood Flow in the Thoracic Aorta Using 4D Phase Contrast MRI.
- Author
-
Jochen von Spiczak, Gerard Crelier, Daniel Giese, Sebastian Kozerke, David Maintz, and Alexander Christian Bunck
- Subjects
Medicine ,Science - Abstract
Phase contrast MRI allows for the examination of complex hemodynamics in the heart and adjacent great vessels. Vortex flow patterns seem to play an important role in certain vascular pathologies. We propose two- and three-dimensional metrics for the objective quantification of aortic vortex blood flow in 4D phase contrast MRI.For two-dimensional vorticity assessment, a standardized set of 6 regions-of-interest (ROIs) was defined throughout the course of the aorta. For each ROI, a heatmap of time-resolved vorticity values [Formula: see text] was computed. Evolution of minimum, maximum, and average values as well as opposing rotational flow components were analyzed. For three-dimensional analysis, vortex core detection was implemented combining the predictor-corrector method with λ2 correction. Strength, elongation, and radial expansion of the detected vortex core were recorded over time. All methods were applied to 4D flow MRI datasets of 9 healthy subjects, 2 patients with mildly dilated aorta, and 1 patient with aortic aneurysm.Vorticity quantification in the 6 standardized ROIs enabled the description of physiological vortex flow in the healthy aorta. Helical flow developed early in the ascending aorta (absolute vorticity = 166.4±86.4 s-1 at 12% of cardiac cycle) followed by maximum values in mid-systole in the aortic arch (240.1±45.2 s-1 at 16%). Strength, elongation, and radial expansion of 3D vortex cores escalated in early systole, reaching a peak in mid systole (strength = 241.2±30.7 s-1 at 17%, elongation = 65.1±34.6 mm at 18%, expansion = 80.1±48.8 mm2 at 20%), before all three parameters similarly decreased to overall low values in diastole. Flow patterns were considerably altered in patient data: Vortex flow developed late in mid/end-systole close to the aortic bulb and no physiological helix was found in the aortic arch.We have introduced objective measures for quantification of vortical flow in 4D phase contrast MRI. Vortex blood flow in the thoracic aorta could be consistently described in all healthy volunteers. In patient data, pathologically altered vortex flow was observed.
- Published
- 2015
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.