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Featured researches published by Simon Veldhoen.


American Journal of Cardiology | 2010

Frequency and Age-Related Course of Mitral Valve Dysfunction in the Marfan Syndrome

Meike Rybczynski; T. S. Mir; Sara Sheikhzadeh; A. Bernhardt; Claudia Schad; Hendrik Treede; Simon Veldhoen; Eike F. Groene; Kristin Kühne; Dietmar Koschyk; Peter N. Robinson; Jürgen Berger; Hermann Reichenspurner; Thomas Meinertz; Yskert von Kodolitsch

Mitral valve (MV) prolapse (MVP) has a high prevalence of 2% to 3% in the general population and thus constitutes the most common cause of severe nonischemic MV regurgitation (MVR). MVP is also common in persons with the Marfan syndrome. However, to date, a large-scale population-based cohort study using modern echocardiographic techniques has not been performed, and the frequency of MVP and the relation of MV dysfunction and age have not been investigated. Therefore, we conducted a population-based cohort study of 204 patients (108 males and 96 females, aged 31.2 ± 16.4 years) with classic Marfan syndrome. We performed echocardiographic follow-up of 174 patients for a mean of 4.4 ± 4.3 years. On the initial or subsequent echocardiographic scan, MVP was present in 82 patients (40%), severe MVR in 25 (12%), and MV endocarditis in 5 patients (2.5%). At 30 years of age, the Weibull cumulative distribution was 42.6% (95% confidence interval [CI] 36% to 50%) for MVP, 56.5% (95% CI 49.3% to 64%) for MVR of any degree, 6.7% (95% CI 3.9% to 11.3%) for severe MVR, and 0.92% (95% CI 0.21% to 3.91%) for MV endocarditis. The cumulative hazard for severe MVR and MV endocarditis was estimated to increase with age. MVP was associated with dural ectasia (p = 0.01), ectopia lentis (p = 0.02), and skeletal involvement (p <0.001). Severe MVR was related to tricuspid valve prolapse (p = 0.002) and to the sporadic form of the Marfan syndrome (p = 0.006). In conclusion, MVP was comparatively frequent in patients with the Marfan syndrome and carries an increased risk of progression to severe MVR and endocarditis, especially in older adults.


Journal of Medical Imaging and Radiation Oncology | 2014

256-MDCT for evaluation of urolithiasis: Iterative reconstruction allows for a significant reduction of the applied radiation dose while maintaining high subjective and objective image quality

Simon Veldhoen; Azien Laqmani; Thorsten Derlin; Murat Karul; Diego Hammerle; Jan-Hendrik Buhk; Susanne Sehner; Hans Dieter Nagel; Felix K.-H. Chun; Gerhard Adam; Marc Regier

Multidetector CT (MDCT) is the established imaging modality in diagnostics of urolithiasis. The aim of iterative reconstruction (IR) is to allow for a radiation dose reduction while maintaining high image quality. This study evaluates its performance in MDCT for assessment of urolithiasis.


Radiology | 2017

Self-gated Non–Contrast-enhanced Functional Lung MR Imaging for Quantitative Ventilation Assessment in Patients with Cystic Fibrosis

Simon Veldhoen; Andreas Max Weng; Janine Knapp; Andreas Steven Kunz; Daniel Stäb; Clemens Wirth; Florian Segerer; Helge Hebestreit; Uwe Malzahn; Herbert Köstler; Thorsten A. Bley

Purpose To assess the clinical feasibility of self-gated non-contrast-enhanced functional lung (SENCEFUL) magnetic resonance (MR) imaging for quantitative ventilation (QV) imaging in patients with cystic fibrosis (CF). Materials and Methods Twenty patients with CF and 20 matched healthy volunteers underwent functional 1.5-T lung MR imaging with the SENCEFUL imaging approach, in which a two-dimensional fast low-angle shot sequence is used with quasi-random sampling. The lungs were manually segmented on the ventilation-weighted images to obtain QV measurements, which were compared between groups. QV values of the patients were correlated with results of pulmonary function testing. Three radiologists rated the images for presence of ventilation deficits by means of visual inspection. Mann-Whitney U tests, receiver operating characteristic analyses, Spearman correlations, and Gwet agreement coefficient analyses were used for statistical analysis. Results QV of the entire lungs was lower for patients with CF than for control subjects (mean ± standard deviation, 0.09 mL/mL ± 0.03 vs 0.11 mL/mL ± 0.03, respectively; P = .007). QV ratios of upper to lower lung halves were lower in patients with CF than in control subjects (right, 0.84 ± 0.2 vs 1.16 ± 0.2, respectively [P < .001]; left, 0.88 ± 0.3 vs 1.11 ± 0.1, respectively [P = .017]). Accordingly, ventilation differences between the groups were larger in the upper halves (Δ = 0.04 mL/mL, P ≤ .001-.002). QV values of patients with CF correlated with forced vital capacity (r = 0.7; 95% confidence interval [CI]: 0.21, 0.91), residual volume (static hyperinflation, r = -0.8; 95% CI: -0.94, 0.42), and forced expiratory volume in 1 second (airway obstruction, r = 0.7; 95% CI: 0.21, 0.91). Disseminated small ventilation deficits were the most frequent involvement pattern, present in 40% of the functional maps in CF versus 8% in the control subjects (P < .001). Conclusion SENCEFUL MR imaging is feasible for QV assessment. Less QV, especially in upper lung parts, and correlation to vital capacity and to markers for hyperinflation and airway obstruction were found in patients with CF.


European Journal of Nuclear Medicine and Molecular Imaging | 2015

Assessment of bone marrow inflammation in patients with myelofibrosis: an 18F-fluorodeoxyglucose PET/CT study

Thorsten Derlin; Haefaa Alchalby; Peter Bannas; Simon Veldhoen; Ivayla Apostolova; Ioanna Triviai; Frank M. Bengel; Nicolaus Kröger

PurposeMyelofibrosis is a haematopoietic stem cell neoplasm characterized by bone marrow inflammation, reactive marrow fibrosis and extramedullary haematopoiesis. The aim of this study was to determine if 18F-FDG PET/CT can be used to noninvasively visualize and quantify the extent and activity of bone marrow involvement.MethodsIn 30 patients, the biodistribution of 18F-FDG was analysed by measuring the standardized uptake value in the bone marrow compartment and spleen. Imaging findings were compared with laboratory, cytogenetic and histopathological data.ResultsRetention of 18F-FDG was observed in bone marrow and spleen. Bone marrow involvement varied, ranging from mildly increased uptake in the central skeleton to extensive uptake in most parts of the skeleton. The extent of bone marrow involvement decreased over time from initial diagnosis (rs = −0.43, p = 0.019). Metabolic activity of the bone marrow decreased as the histopathological grade of fibrosis increased (rs = −0.37, p = 0.04). There was a significant positive correlation between the metabolic activity of the bone marrow and that of the spleen (p = 0.04).Conclusion18F-FDG PET/CT is as a promising technique for the quantitation of bone marrow inflammation in myelofibrosis. Our data indicate that the intensity of bone marrow 18F-FDG uptake decreases as bone marrow fibrosis increases. Further evaluation in prospective studies is required to determine the potential clinical impact and prognostic significance of PET.


Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren | 2017

Diagnosis of Pulmonary Artery Embolism: Comparison of Single-Source CT and 3rd Generation Dual-Source CT using a Dual-Energy Protocol Regarding Image Quality and Radiation Dose

Bernhard Petritsch; Aleksander Kosmala; Tobias Gassenmaier; Andreas Max Weng; Simon Veldhoen; Andreas Steven Kunz; Thorsten A. Bley

Purpose To compare radiation dose, subjective and objective image quality of 3 rd generation dual-source CT (DSCT) and dual-energy CT (DECT) with conventional 64-slice single-source CT (SSCT) for pulmonary CTA. Materials and Methods 180 pulmonary CTA studies were performed in three patient cohorts of 60 patients each. Group 1: conventional SSCT 120 kV (ref.); group 2: single-energy DSCT 100 kV (ref.); group 3: DECT 90/Sn150 kV. CTDIvol, DLP, effective radiation dose were reported, and CT attenuation (HU) was measured on three central and peripheral levels. The signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. Two readers assessed subjective image quality according to a five-point scale. Results Mean CTDIvol and DLP were significantly lower in the dual-energy group compared to the SSCT group (p < 0.001 [CTDIvol]; p < 0.001 [DLP]) and the DSCT group (p = 0.003 [CTDIvol]; p = 0.003 [DLP]), respectively. The effective dose in the DECT group was 2.79 ± 0.95 mSv and significantly smaller than in the SSCT group (4.60 ± 1.68 mSv, p < 0.001) and the DSCT group (4.24 ± 2.69 mSv, p = 0.003). The SNR and CNR were significantly higher in the DSCT group (p < 0.001). Subjective image quality did not differ significantly among the three protocols and was rated good to excellent in 75 % (135/180) of cases with an inter-observer agreement of 80 %. Conclusion Dual-energy pulmonary CTA protocols of 3 rd generation dual-source scanners allow for significant reduction of radiation dose while providing excellent image quality and potential additional information by means of perfusion maps. Key Points: · Dual-energy CT with 90/Sn150 kV configuration allows for significant dose reduction in pulmonary CTA.. · Subjective image quality was similar among the three evaluated CT-protocols (64-slice SSCT, single-energy DSCT, 90/Sn150 kV DECT) and was rated good to excellent in 75% of cases.. · Dual-energy CT provides potential additional information by means of iodine distribution maps.. Citation Format · Petritsch B, Kosmala A, Gassenmaier T et al. Diagnosis of Pulmonary Artery Embolism: Comparison of Single-Source CT and 3rd Generation Dual-Source CT using a Dual-Energy Protocol Regarding Image Quality and Radiation Dose. Fortschr Röntgenstr 2017; 189: 527 - 536.


Circulation-cardiovascular Imaging | 2016

Acute Pulmonary Artery Embolism Detected by Noncontrast Functional Lung Magnetic Resonance Imaging

Christian Kestler; Andreas Max Weng; Andreas Steven Kunz; Mona Laubmeier; Clemens Wirth; Herbert Köstler; Thorsten A. Bley; Simon Veldhoen

A 30-year-old woman presented to the emergency department with acute shortness of breath, dizziness, and left-sided thoracic pain. The patient had been diagnosed with adenocarcinoma of the lung and metastases in central nervous system, liver, and bones 2 years earlier. After initial radiation and chemotherapeutic treatment, the patient showed a mixed response and was subsequently treated with the tyrosine-kinase inhibitor crizotinib, as well as further radiation of the progressive and symptomatic cerebral metastases. On admission, the patient was afebrile, displayed unimpaired oxygen saturation in room air, and presented with mild pitting edema of the calves. The ECG was without pathological findings and d-dimers were slightly elevated. Because of her clinical presentation and the increased pretest probability (clinical presentation and cancer diagnosis), a contrast-enhanced multidetector computed tomography was conducted to test for pulmonary embolism (PE). Multidetector computed tomography, however, showed no thrombotic mass in the main and segmental pulmonary arteries but a subpleural wedge-shaped consolidation, rated suspicious for beginning ischemic pneumonia, for example, because of subsegmental embolism, which is commonly missed by conventional multidetector computed tomography (Figure 1). The patient consecutively underwent ventilation and perfusion single-photon emission computed tomography (SPECT), which revealed a mismatch consisting of a perfusion defect in segments 8 and 9 of the left lower lobe …


Zeitschrift Fur Medizinische Physik | 2017

Comparison of Turbo Spin Echo and Echo Planar Imaging for intravoxel incoherent motion and diffusion tensor imaging of the kidney at 3 Tesla

Fabian Hilbert; Tobias Wech; Henning Neubauer; Simon Veldhoen; Thorsten A. Bley; Herbert Köstler

Echo Planar Imaging (EPI) is most commonly applied to acquire diffusion-weighted MR-images. EPI is able to capture an entire image in very short time, but is prone to distortions and artifacts. In diffusion-weighted EPI of the kidney severe distortions may occur due to intestinal gas. Turbo Spin Echo (TSE) is robust against distortions and artifacts, but needs more time to acquire an entire image compared to EPI. Therefore, TSE is more sensitive to motion during the readout. In this study we compare diffusion-weighted TSE and EPI of the human kidney with regard to intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI). Images were acquired with b-values between 0 and 750s/mm2 with TSE and EPI. Distortions were observed with the EPI readout in all volunteers, while the TSE images were virtually distortion-free. Fractional anisotropy of the diffusion tensor was significantly lower for TSE than for EPI. All other parameters of DTI and IVIM were comparable for TSE and EPI. Especially the main diffusion directions yielded by TSE and EPI were similar. The results demonstrate that TSE is a worthwhile distortion-free alternative to EPI for diffusion-weighted imaging of the kidney at 3Tesla.


Investigative Radiology | 2016

Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Quantitative Lung Perfusion Imaging Using the Dual-Bolus Approach: Comparison of 3 Contrast Agents and Recommendation of Feasible Doses.

Simon Veldhoen; Markus Oechsner; André Fischer; Andreas Max Weng; Andreas Steven Kunz; Thorsten A. Bley; Herbert Köstler; Christian Ritter

ObjectiveThe aims of this study were to compare 3 contrast agents and to define feasible doses for quantitative lung perfusion imaging using the dual-bolus approach in dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Materials and MethodsTen healthy volunteers (6 males, 4 females; mean age, 23.5 years) underwent DCE-MRI at 1.5 T using a 3D FLASH sequence. After a prebolus, 3 doses of gadopentetate dimeglumine (Gd-DTPA), gadofosveset, and gadobenate dimeglumine (Gd-BOPTA) were evaluated. Dose regimes were as follows: Gd-DTPA: 3.0 mL, 6.0 mL, and 12.0 mL with 1.5 mL prebolus; gadofosveset: 1.5 mL, 3.0 mL, and 6.0 mL with 0.8 mL prebolus; and Gd-BOPTA: 1.5 mL, 3.0 mL, and 6.0 mL with 0.8 mL prebolus. Pulmonary blood flow (PBF), pulmonary distribution volume, and mean transit time were assessed for each bolus. Region of interest measurements were used to determine the arterial input function (AIF) in the pulmonary trunk and signal intensities in lung parenchyma. Two radiologists independently rated the subjective image quality of the quantitative perfusion maps based on a 4-point Likert scale. ResultsDose-dependent signal saturation effects were observed for all 3 contrast agents concerning AIF and parenchyma measurements. Signal yields were comparable using Gd-BOPTA (AIF, 214.49 arbitrary units [AU]; parenchyma, 41.7 AU) and Gd-DTPA (207.43 AU; 36.3 AU). Gadofosveset showed significantly lower signal yield (165.74 AU; 25.2 AU; p < 0.008). Highest signal increase was observed for Gd-DTPA. Using Gd-DTPA, mean PBF values for the 3 doses (3 mL, 6 mL, 12 mL) in mL/min per milliliter lung volume were 2.9 ± 1.5, 2.4 ± 1.1, and 1.6 ± 1.0. For the 3 doses of gadofosveset (1.5 mL, 3 mL, 6 mL) mean PBF results were 3.1 ± 1.1, 1.9 ± 0.7, and 1.2 ± 0.6. Last, mean PBF values for Gd-BOPTA (1.5 mL, 3 mL, 6 mL) were 3.4 ± 1.7, 2.8 ± 1.3, and 2.0 ± 0.8. Measurements provided consistent values for all perfusion parameters (PBF, pulmonary distribution volume, mean transit time) when compared with reference literature. Contrast dose volume and the applied contrast agent had no relevant effects on the image quality scores. ConclusionsThe dual-bolus approach using a 3D FLASH sequence is a feasible tool for quantitative lung perfusion imaging. Small boluses of 3 mL for Gd-DTPA, 1.5 mL for Gd-BOPTA, and 1.5 mL for gadofosveset provide sufficient signal yield for quantitative parenchyma measurements. Using higher boluses falsely lower perfusion values have to be considered due to signal saturation effects. Although gadofosveset yielded the lowest signal, the generated quantitative perfusion maps were of diagnostic quality.


Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren | 2013

Pediatric Patients with Marfan Syndrome: Frequency of Dural Ectasia and its Correlation with Common Cardiovascular Manifestations

Simon Veldhoen; Veronika Stark; Götz Mueller; Thorsten Derlin; Thorsten A. Bley; Jochen Weil; Y. von Kodolitsch; T. S. Mir

PURPOSE Marfan syndrome (MFS) is a genetic disorder of the connective tissue. Aortic root dilation is a main criterion of the Ghent Nosology. Dural ectasia and the presence of mitral valve prolapse (MVP) contribute to its systemic score. The purpose of this study was to investigate the frequency of dural ectasia and its correlation with cardiovascular manifestations in a pediatric study population. PATIENTS AND METHODS 119 pediatric patients with confirmed or suspected MFS were examined in the local Marfan Clinic. 31 children with MFS who underwent magnetic resonance imaging (MRI) were included. Each patient was evaluated according to the Ghent nosology. Echocardiography was used to measure the aortic root diameter and assess the presence of MVP and mitral regurgitation. Z-scores were calculated for the evaluation of the aortic root diameters. MRI was performed to determine the dural sac ratio (DSR). RESULTS The prevalence of dural ectasia was 90.3 %, of aortic root dilation 32.2 %, of MVP 64.5 % and of mitral regurgitation 51.6 %. DSR at L5 correlated with the intraindividual z-scores (slope, 3.62 ± 1.5 [0.56; 6.68]; r = 0.17; p = 0.02; F = 5.84). Z-scores ≥ 2 were accompanied by dural ectasia in 100 %, MVP in 95 % and mitral regurgitation in 100 % of cases. MVP was accompanied by mitral regurgitation in 70 % of cases. CONCLUSION As the examined cardiac manifestations show a coincidence with dural ectasia in 95 - 100 % of cases, MRI for diagnostic dural sac imaging should be reserved for MFS suspicions with the absence of those manifestations in order to establish the diagnosis according to the Ghent criteria. Thus, the present study supports the recent downgrading of dural ectasia to a contributor to the systemic score.


World Journal of Clinical Pediatrics | 2017

Off-label-use of sulfur-hexafluoride in voiding urosonography for diagnosis of vesicoureteral reflux in children: A survey on adverse events

Alexander Sauer; Clemens Wirth; Isabel Platzer; Henning Neubauer; Simon Veldhoen; Alexander Dierks; Reinhard Kaiser; Andreas Steven Kunz; Meinrad Beer; Thorsten A. Bley

AIM To evaluate the risk profile of sulfur hexafluoride in voiding urosonography (VUS) based on a large cohort of children. METHODS Since 2011 sulfur hexafluoride (SH, SonoVue®, Bracco, Italy) is the only ultrasound contrast available in the European Union and its use in children has not been approved. Within a 4-year-period, 531 children with suspected or proven vesicoureteral reflux (f/m = 478/53; mean age 4.9 years; 1 mo-25.2 years) following parental informed consent underwent VUS with administration of 2.6 ± 1.2 mL SH in a two-center study. A standardized telephone survey on adverse events was conducted three days later. RESULTS No acute adverse reactions were observed. The survey revealed subacute, mostly self-limited adverse events in 4.1% (22/531). The majority of observed adverse events (17/22) was not suspected to be caused by an allergic reaction: Five were related to catheter placement, three to reactivated urinary tract infections, five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold. In five patients (0.9%) hints to a potential allergic cause were noted: Perineal urticaria was reported in three interviews and isolated, mild fever in two. These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary. Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH. CONCLUSION No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%.

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