Aktivität der sezernierten Sphingomyelinase bei akuter und chronischer systemischer Inflammation am Beispiel des SIRS, der Sepsis und der chronischen Herzinsuffizienz

Systemic inflammatory response syndrome (SIRS), Sepsis und chronische Herzinsuffizienz (CHF) sind gekennzeichnet durch eine generalisierte Inflammationsreaktion mit Hyperzytokinämie, vermehrtem oxidativen Stress, hämodynamischen und metabolischen Veränderungen. Erste Beobachtungen am Menschen haben gezeigt, dass sich generalisierte Entzündungsprozesse auch in systemischen Veränderungen des Sphingomyelinstoffwechsel niederschlagen. Metabolite des Sphingomyelinstoffwechsel sind an der zellulären Stressantwort beteiligt und greifen regulativ in die unterschiedlichsten Immunfunktionen ein. Daneben lassen sich kardiovaskuläre und metabolische Effekte beobachten. Sphingomyelinasen nehmen als Schrittmacherenzyme eine Schlüsselposition im Sphingomyelinstoffwechsel ein. Welche Rolle der sezernierten Sphingomyelinase (sSMPD1) in einer systemischen Aktivierung des Sphingomyelinstoffwechsels zukommt, ist bisher nur unzureichend untersucht. Ziele Wir gingen der Frage nach, inwieweit akute und chronische generalisierte Inflammationszustände beim Menschen mit einer veränderten Aktivität der sezernierten Sphingomyelinase einhergehen. Darüber hinaus sollte geklärt, ob ein Zusammenhang zwischen Krankheitsschwere und Ausmaß der sSMPD1 Aktivitätsänderung besteht. Dabei untersuchten wir auch mögliche Mechanismen der Aktivitätssteigerung. Schließlich untersuchten wir den Zusammenhang zwischen sSMPD1 Aktivität und verschiedenen Funktionsparametern der chronischen Herzinsuffizienz

Dual-Source CT Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

Purpose. To test different peripheral arterial stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation and image noise in dual-source multidetector row CT (DSCT) in vitro. Methods and Materials. 22 stents (nitinol, steel, cobalt-alloy, tantalum, platinum alloy) were examined in a vessel phantom. All stents were imaged in axial orientation with standard parameters. Image reconstructions were obtained with four different convolution kernels. To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density and noise were measured. Results. The mean percentage of the visible stent lumen diameter from the nominal stent diameter was 74.5% ± 5.7 for the medium-sharp kernel, 72.8% ± 6.4 for the medium, 70.8% ± 6.4 for the medium-smooth and 67.6% ± 6.6 for the smooth kernel. Mean values of lumen attenuation were 299.7HU ± 127 (medium-sharp), 273.9HU ± 68 (medium), 270.7HU ± 53 (medium-smooth) and 265.8HU ± 43. Mean image noise was: 54.6 ± 6.3, 20.5 ± 1.7, 16.3 ± 1.7, 14.0 ± 2 respectively. Conclusion. Visible stent lumen diameter varies depending on stent type and scan parameters. Lumen diameter visibility increases with the sharpness of the reconstruction kernel. Smoother kernels provide more realistic density measurements inside the stent lumen and less image noise

Cardiovascular magnetic resonance feature tracking derived strain parameters in patients with acute myocarditis and preserved ejection fraction : A validation study

[No abstract available

Reproducibility of three different cardiac T2-mapping sequences at 1.5T and impact of cofactors on T2-relaxation times

Background: The high interindividual variability of myocardial T2 relaxation times appears to be one of the main challenges for the clinical application of cardiac T2-mapping. This study therefore aimed to evaluate potential underlying causes for this variability, analyzing the reproducibility of three different cardiac T2-mapping sequences and evaluating the influence of cofactors on T2 relaxation times. Methods: 30 healthy volunteers were examined three times on a clinical 1.5T scanner (scan 1: in the morning; scan 2: in the evening of the same day; scan 3: in the evening 2-3 weeks later). In each examination three different T2-mapping sequences were acquired at three slices in short axis view: Multi Echo Spin Echo (MESE), T2-prepared balanced Steady State Free Precession (T2prep; [1]) and Gradient Spin Echo (GraSE). Repeated measurements were performed for T2prep and GraSE. Segmented T2-maps were generated for each slice according to the AHA 17-segment model. Intra- and inter-observer reproducibility was tested in a subgroup of 10 randomly selected subjects, where manual ROIs were drawn independently to measure T2 values of each segment blinded to the other results. Results: Overall, we observed no systematic difference of T2 times due to diurnal effects and on long-term analysis. Differentiated analysis of variance components for all sequences, however, revealed a greater variance of T2 times over multiple time points than for repeated measurements within the same scan. Our study revealed a low intra-observer and inter-observer variability of manual ROI-definition and the acquired T2 times for each sequence. The coefficients of variation and intraclass correlation coefficients for intra-observer variability were: 1.3% and 0.89 for T2prep, 1.5% and 0.93 for GraSE, 3.1% and 0.83 for MESE; and for inter-observer variability: 3.3% and 0.66 for T2prep, 2.0% and 0.83 for GraSE, 3.6% and 0.77 for MESE. With respect to the influence of potential cofactors on T2 times, we observed a negative effect of the cofactor heart rate on mean T2 values, yet this effect proved to be not significant. Conversely, we found significant and positive relation between mean T2 times and the cofactors age, weight and height (p < 0.005, p < 0.05 and p < 0.05) in single linear regression models. Using multiple regression models, we observed significant relations between mean T2 times and age (p < 0.005), gender (p < 0.01), and either weight or height (p < 0.005), for given values of the remaining cofactors. Conclusions: Intra- and inter-observer reproducibility of all tested T2-mapping sequnces is high, thereby confirming previous studies. According to our study, the high interindividual variability of myocardial T2 relaxation times is most likely due to proband-related effects such as age, gender, weight and height and other cofactors intraindividually varying with time

A novel multiparametric imaging approach to acute myocarditis using T2-mapping and CMR feature tracking

Background: The aim of this study was to evaluate the diagnostic potential of a novel cardiovascular magnetic resonance (CMR) based multiparametric imaging approach in suspected myocarditis and to compare it to traditional Lake Louise criteria (LLC). Methods: CMR data from 67 patients with suspected acute myocarditis were retrospectively analyzed. Seventeen age- and gender-matched healthy subjects served as control. T2-mapping data were acquired using a Gradient-Spin-Echo T2-mapping sequence in short-axis orientation. T2-maps were segmented according to the 16-segments AHA-model and segmental T2 values and pixel-standard deviation (SD) were recorded. Afterwards, the parameters maxT2 (the highest segmental T2 value) and madSD (the mean absolute deviation (MAD) of the pixel-SDs) were calculated for each subject. Cine sequences in three long axes and a stack of short-axis views covering the left and right ventricle were analyzed using a dedicated feature tracking algorithm. Results: A multiparametric imaging model containing madSD and LV global circumferential strain (GCSLV) resulted in the highest diagnostic performance in receiver operating curve analyses (area under the curve [AUC] 0.84) when compared to any model containing a single imaging parameter or to LLC (AUC 0.79). Adding late gadolinium enhancement (LGE) to the model resulted in a further increased diagnostic performance (AUC 0.93) and yielded the highest diagnostic sensitivity of 97% and specificity of 77%. Conclusions: A multiparametric CMR imaging model including the novel T2-mapping derived parameter madSD, the feature tracking derived strain parameter GCSLV and LGE yields superior diagnostic sensitivity in suspected acute myocarditis when compared to any imaging parameter alone and to LLC. © 2017 The Author(s)

Quantification of biventricular myocardial function using cardiac magnetic resonance feature tracking, endocardial border delineation and echocardiographic speckle tracking in patients with repaired tetralogy of fallot and healthy controls

BACKGROUND: Parameters of myocardial deformation have been suggested to be superior to conventional measures of ventricular function in patients with tetralogy of Fallot (ToF), but have required non-routine, tagged cardiovascular magnetic resonance (CMR) techniques. We assessed biventricular myocardial function using CMR cine-based feature tracking (FT) and compared it to speckle tracking echocardiography (STE) and to simple endocardial border delineation (EBD). In addition, the relation between parameters of myocardial deformation and clinical parameters was assessed. METHODS: Overall, 28 consecutive adult patients with repaired ToF (age 40.4 ± 13.3 years) underwent standard steady-state-free precession sequence CMR, echocardiography, and cardiopulmonary exercise testing. In addition, 25 healthy subjects served as controls. Myocardial deformation was assessed by CMR based FT (TomTec Diogenes software), CMR based EBD (using custom written software) and STE (TomTec Cardiac Performance Analysis software). RESULTS: Feature tracking was feasible in all subjects. A close agreement was found between measures of global left (LV) and right ventricular (RV) global strain. Interobserver agreement for FT and STE was similar for longitudinal LV global strain, but FT showed better inter-observer reproducibility than STE for circumferential or radial LV and longitudinal RV global strain. Reproducibility of regional strain on FT was, however, poor. The relative systolic length change of the endocardial border measured by EBD yielded similar results to FT global strain. Clinically, biventricular longitudinal strain on FT was reduced compared to controls (P < 0.0001) and was related to the number of previous cardiac operations. In addition, FT derived RV strain was related to exercise capacity and VE/VCO(2)-slope. CONCLUSIONS: Although neither the inter-study reproducibility nor accuracy of FT software were investigated, and its inter-observer reproducibility for regional strain calculation was poor, its calculations of global systolic strain showed similar or better inter-oberver reproducibility than those by STE, and could be applied across RV image regions inaccessible to echo. ‘Global strain’ calculated by EBD gave similar results to FT. Measurements made using FT related to exercise tolerance in ToF patients suggesting that the approach could have clinical relevance and deserves further study

MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid) stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy) were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm) filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results). Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy). 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy) and 6 stents showed poor results (1x nitinol, and 5x 316L). Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique

Quantification of biventricular myocardial function using cardiac magnetic resonance feature tracking, endocardial border delineation and echocardiographic speckle tracking in patients with repaired tetralogy of fallot and healthy controls

Background: Parameters of myocardial deformation have been suggested to be superior to conventional measures of ventricular function in patients with tetralogy of Fallot (ToF), but have required non-routine, tagged cardiovascular magnetic resonance (CMR) techniques. We assessed biventricular myocardial function using CMR cine-based feature racking (FT) and compared it to speckle tracking echocardiography (STE) and to simple endocardial border delineation (EBD). In addition, the relation between parameters of myocardial deformation and clinical parameters was assessed. Methods: Overall, 28 consecutive adult patients with repaired ToF (age 40.4 ± 13.3 years) underwent standard steadystate- free precession sequence CMR, echocardiography, and cardiopulmonary exercise testing. In addition, 25 healthy subjects served as controls. Myocardial deformation was assessed by CMR based FT (TomTec Diogenes software), CMR based EBD (using custom written software) and STE (TomTec Cardiac Performance Analysis software). Results: Feature tracking was feasible in all subjects. A close agreement was found between measures of global left (LV) and right ventricular (RV) global strain. Interobserver agreement for FT and STE was similar for longitudinal LV global strain, but FT showed better inter-observer reproducibility than STE for circumferential or radial LV and longitudinal RV global strain. Reproducibility of regional strain on FT was, however, poor. The relative systolic length change of the endocardial border measured by EBD yielded similar results to FT global strain. Clinically, biventricular longitudinal strain on FT was reduced compared to controls (P<0.0001) and was related to the number of previous cardiac operations. In addition, FT derived RV strain was related to exercise capacity and VE/VCO2-slope. Conclusions: Although neither the inter-study reproducibility nor accuracy of FT software were investigated, and its interobserver reproducibility for regional strain calculation was poor, its calculations of global systolic strain showed similar or better inter-oberver reproducibility than those by STE, and could be applied across RV image regions inaccessible to echo. ‘Global strain’ calculated by EBD gave similar results to FT. Measurements made using FT related to exercise tolerance in ToF patients suggesting that the approach could have clinical relevance and deserves further study