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Bob Weijs,
Yuri Blaauw,
Roger J M W Rennenberg,
Leon J Schurgers,
Carl C M M Timmermans,
Laurent Pison,
Robby Nieuwlaat,
Leonard Hofstra,
Abraham A Kroon, Joachim Wildberger,
Harry J G M Crijns
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ABSTRACT: Vitamin K antagonists (VKA) are currently the most frequently used drug to prevent ischaemic stroke in atrial fibrillation (AF) patients. However, VKA use has been associated with increased vascular calcification. The aim of this study was to investigate the contribution of VKA use to coronary artery calcification in low-risk AF patients.
A prospective coronary calcium scan was performed in 157 AF patients without significant cardiovascular disease (108 males; mean age 57 ± 9 years). A total of 71 (45%) patients were chronic VKA users. The duration of VKA treatment varied between 6 and 143 months (mean 46 months). No significant differences in clinical characteristics were found between patients on VKA treatment and non-anticoagulated patients. However, median coronary artery calcium scores differed significantly between patients without and patients with VKA treatment [0, inter-quartile range (IQR) 0-40, vs. 29, IQR 0-184; P = 0.001]. Mean coronary calcium scores increased with the duration of VKA use (no VKA: 53 ± 115, 6-60 months on VKA: 90 ± 167, and >60 months on VKA: 236 ± 278; P < 0.001). Multivariable logistic regression analysis revealed that age and VKA treatment were significantly related to increased coronary calcium score.
Patients using VKA show increased levels of coronary calcification. Age and VKA treatment were independently related to increased coronary calcium score.
European Heart Journal 07/2011; 32(20):2555-62. · 10.48 Impact Factor
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Journal of Cardiovascular Magnetic Resonance. 01/2011;
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European Journal of Heart Failure 03/2010; 12(3):227-31. · 4.90 Impact Factor
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ABSTRACT: A solitary fibrous tumor of the kidney is a rare neoplasm that was often misdiagnosed as hemangiopericytoma, until recently. We report a case of a 35-year-old male patient with a solid, 7 cm tumor located centrally in a solitary right kidney. The patient underwent successful bench surgery and autotransplantation.
The Canadian Journal of Urology 10/2009; 16(5):4854-6. · 0.64 Impact Factor
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ABSTRACT: Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis.
European Radiology 08/2009; 20(2):469-76. · 3.22 Impact Factor
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Florian F Behrendt,
Philipp Bruners,
John Kalafut,
Andreas H Mahnken,
Sebastian Keil,
Cedric Plumhans,
Marco Das,
Sven Stanzel, Joachim E Wildberger,
Jochen Pfeffer,
Rolf W Günther,
Georg Mühlenbruch
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ABSTRACT: To develop a circulation phantom with physiologic circulation parameters, including a pulmonary and a body circulation for the evaluation of intravascular contrast material (CM) application.
The circulation phantom consists of a low-pressure venous system into which CM is injected, a pulmonary circulation, and high-pressure body circulation with an anthropometric aorta and coronary arteries. The phantom is driven by a pulsatile Harvard heart pump. Venous and arterial pressure were set to physiologic values with heart rate (60 beats/min), stroke volume (60 mL), and ratio of diastole to systole (60/40) also were within physiologic limits. CM with different iodine concentrations (300, 370, and 400 mg iodine/mL) were injected at a flow rate of 4 mL/s (iodine delivery rate: 1.2 g, 1.48 g, and 1.6 g iodine/s, respectively; total iodine load for all protocols: 36 g). Serial computed tomography scans at the level of the pulmonary artery, the ascending and the descending aorta replica were obtained. Dynamic pressure in the phantom and true injection system parameters (flow rate, injection pressure, and CM volume) was continuously monitored. Time-enhancement curves were calculated, and pulmonary and aortic peak time and enhancement were determined. Results were compared using nonparametric unpaired Wilcoxon tests.
The pressure in the phantom showed physiologic values for the low (mean pressure: 15 mm Hg) and high pressure part (125/75 mm Hg). Programmed injection values (flow rate, pressure, and volume) were reached for all injections. Using CM with 400 mg iodine/mL, the shortest pulmonary and aortic peak times and the highest pulmonary and aortic peak enhancement values were obtained compared with CM with 300 and 370 mg iodine/mL.
We developed a flow phantom with physiologic circulation parameters for measurement of contrast enhancement. The phantom is suitable for further evaluation of CM injection protocols for pulmonary and aortic enhancement.
Investigative radiology 11/2008; 43(10):729-36. · 4.85 Impact Factor
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Michael Becker,
Alexandra Lenzen,
Christina Ocklenburg,
Katharina Stempel,
Harald Kühl,
Miria Neizel,
Markus Katoh,
Rafael Kramann, Joachim Wildberger,
Malte Kelm,
Rainer Hoffmann
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ABSTRACT: This study evaluated the predictive value of myocardial deformation imaging for improvement in cardiac function after revascularization therapy in comparison with contrast-enhanced cardiac magnetic resonance imaging (ceMRI).
Myocardial deformation imaging allows analysis of myocardial viability in ischemic left ventricular dysfunction.
In 53 patients with ischemic left ventricular dysfunction, myocardial viability was assessed using pixel-tracking-derived myocardial deformation imaging and ceMRI to predict recovery of function at 9 +/- 2 months follow-up. For each left ventricular segment in a 16-segment model, peak systolic radial strain was determined from parasternal 2-dimensional echocardiographic views using an automatic frame-by-frame tracking system of natural acoustic echocardiographic markers (EchoPAC, GE Ultrasound, Horton, Norway), and the relative extent of hyperenhancement using ceMRI.
Of 463 segments with abnormal baseline function, 227 showed regional recovery. Compared with segments showing functional improvement, those that failed to recover had lower peak radial strain (15.2 +/- 7.5% vs. 22.6 +/- 6.3%; p < 0.001) and a greater extent of hyperenhancement (56 +/- 29% vs. 14 +/- 17%; p < 0.001). Using a cutoff of 17.2% for peak systolic radial strain, functional recovery could be predicted with high accuracy (sensitivity 70.2%, specificity 85.1%, area under the curve 0.859, 95% confidence interval 0.825 to 0.893). The predictive value was similar to that of hyperenhancement by ceMRI (sensitivity 71.6%, specificity 92.1%, area under the curve 0.874, 95% confidence interval 0.840 to 0.901, at a cutoff of 43% hyperenhancement).
Myocardial deformation imaging based on frame-to-frame tracking of acoustic markers in 2-dimensional echocardiographic images is a powerful novel modality to identify reversible myocardial dysfunction.
Journal of the American College of Cardiology 04/2008; 51(15):1473-81. · 14.16 Impact Factor
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ABSTRACT: Image quality of chest and abdominal computed tomographic (CT) scans was evaluated at different doses to assess the lowest value of x-ray dose at which the image quality was not being affected.
Using multislice CT (MSCT), 29 patients who submitted to follow-up examinations were examined using a combined MSCT protocol of the chest and the abdomen on 4-raw MSCT (Siemens, Erlangen, Germany). For each examination, approximately 120 mL of contrast agent (Bracco-Altana, Konstanz, Germany) was applied intravenously. The raw data were transferred to an external personal computer equipped with an image reconstruction software (CardioRecon 6; Siemens, Forchheim, Germany) to simulate 5 different dose levels. To simulate them correctly, a milliampere second-dependent noise was added to every image, so that the changes in a current-time product could be imitated. The images were compared in consensus by 2 radiologists who were not informed about the technical scanning parameters, that is, dose parameters, and were graded in 4 different subcategories on a 1-to-5-point scale. For statistical analysis, the Friedman test was used. Additional evaluations for lesions smaller than 1.0 cm were performed and analyzed separately.
For image noise, there was a significant change between 40 and 60 mA s. For lesion detection, there was no significant change. The contour of the small objects did not differ between 90, 60, and 40 mA s. However, a dose reduction to 30 mA s had a significant effect. The contrast did not differ between 90, 60, 40, and even down to 30 mA s. Only a maximal dose reduction to 20 mA s had a significant effect on the contrast. The level of noise was most sensitive to the current. Whereas a dose reduction to 60 mA s did not yet have a significant effect, there was a significant increase of noise at 40 mA s.
The MSCT can be applied with a lower dose than that usually selected in examinations at present to follow-up and stage the oncological patients adequately.
Journal of computer assisted tomography 34(2):302-8. · 1.38 Impact Factor
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ABSTRACT: To evaluate the effect of different image reconstruction parameters on quantitative automated measurements of pulmonary emphysema in chest multidetector-row spiral computed tomography.
Thirty patients with known emphysema underwent multidetector-row spiral computed tomography. Retrospective reconstruction with a soft tissue kernel (Siemens B20 at 1-mm, 2-mm, and 3-mm slices) and 4 alternative kernel grades (from smooth to sharp: Siemens B30, B40, B50, B60 at 1-mm slices) was performed. Total lung volume, emphysema volume (EV), 15th percentile density, and 4 EV clusters were quantified. Results were compared with those of standard algorithm B20/1-mm slices.
Differences in total lung volume were less than 0.2%. Alternative kernel grades resulted in a significantly increased average EV. The 15th percentile density showed a significant average difference for all alternative algorithms. The large emphysema cluster showed a significant change for reconstruction algorithms B50, B60, B20/2 mm and B20/3 mm.
Pulmonary EV is significantly affected by different reconstruction algorithms.
Journal of computer assisted tomography 32(6):899-904. · 1.38 Impact Factor
