Evaluation of a shortened cardiac MRI protocol for left ventricular examinations: diagnostic performance of T1-mapping and myocardial function analysis.

BACKGROUND: In this study we sought to retrospectively evaluate whether a very brief cardiac magnetic resonance imaging (CMR) protocol sufficiently distinguishes patients with relevant myocardial changes with need for further examination from healthy subjects. METHODS: Patients with clinical indication for CMR (n = 160) were included in the study. Patients were categorized into two groups depending on presence of left ventricular (LV) dysfunction. ROC-analysis was done for results of T1-, T2- mapping and extracellular volume evaluation in patients without LV dysfunction. Binary endpoint was correctly depicted pathology of the conventional qualitative CMR techniques and report. RESULTS: In the patient cohort without LV dysfunction (49%), AUC for T1 mapping was 82% (p < 0.001), 60% for T2 mapping (p = 0.1) and 79% for ECV (p < 0.001). T1 mapping was significantly superior to T2 mapping to rule out left ventricular pathology (p = 0.012). Sensitivity for the combined use of T1 mapping and sBTFE cine imaging was 98%; the negative predictive value was 90%. In 49 patients (30%) full protocol CMR did not provide any additional information; T1 mapping correctly detected 57% of the subjects from this group who would not benefit from additional CMR. CONCLUSION: A shortened CMR protocol comprising T1 mapping and LV-function analysis seems suitable to rule out myocardial alterations. Every third patient of the study population did not benefit from full contrast enhanced CMR. The shortened protocol correctly identified every fifth patient who would not benefit but no relevant pathologic findings with the obligation for treatment were missed.

Thrombus Permeability in Admission Computed Tomographic Imaging Indicates Stroke Pathogenesis Based on Thrombus Histology.

Background and Purpose- Intracranial thrombi can be characterized according to their permeability as measured by contrast agent penetration. Thrombus composition and its associated pathogenesis are important factors affecting treatment and secondary prevention. We aimed to explore the histopathologic factors explaining the heterogeneity of thrombus permeability measures and evaluated potential correlations with stroke pathogenesis. Methods- Thrombus densities were measured in thin-slice noncontrast computed tomography and automatically aligned computed tomographic angiography images of 133 patients with large-vessel occlusions of the middle cerebral artery. Change in thrombus attenuation (Δt) and corrected void fraction (ε; attenuation increase corrected for contralateral artery densities) were calculated. First, these thrombus perviousness measures were correlated with histological thrombus components (especially fractions of fibrin-platelet accumulation and red blood cells) and stroke pathogenesis (n=32). For validation, an association between perviousness and pathogenesis was assessed in a second, independent cohort (n=101). Results- Thrombus perviousness estimates were correlated with both fibrin/platelets fractions (Δt: r=0.43, P=0.016/ε: r=0.45, P=0.01) and inversely with red blood cells counts (Δt: r=-0.46, P=0.01/ε: r=-0.49, P=0.006). In the first cohort, Δt was substantially higher in samples from patients with cardioembolic stroke pathogenesis as compared with noncardioembolic-derived thrombi ( P=0.026). In the validation cohort, thrombus perviousness measures differed significantly between cardioembolic (Δt: median [ interquartile range]=12.53 [8.70-17.90]; ε: median [interquartile range]=0.054 [0.036-0.082]) and noncardioembolic thrombi (Δt: median [interquartile range]=3.2 [2.17-6.44], P<0.001; ε: median [interquartile range]=0.020 [0.011-0.027], P<0.001) and were associated with pathogenesis (Δt: ß=0.45, P=0.016/ε: ß=83.6, P=0.013) in a binary logistic regression model. Conclusions- Permeable thrombi showed a strong correlation with lower fractions of red blood cells counts and more fibrin/platelets conglomerations, concurrent with an association with cardioembolic origin. This novel information about thrombus perviousness may be valuable as a new and simple to acquire imaging marker for identifying stroke pathogenesis using early and readily available imaging.

Firewall function of the endothelial glycocalyx in the regulation of sodium homeostasis.

Plasma sodium, slightly above normal and in presence of aldosterone, stiffens vascular endothelium and reduces nitric oxide release with the consequence of endothelial dysfunction. This process is mediated by epithelial sodium channels (ENaC) and, most likely, the endothelial Na(+)/K(+)-ATPase. Both, ENaC and Na(+)/K(+)-ATPase, are located in the plasma membrane of endothelial cells and embedded in the endothelial glycocalyx (eGC). This negatively charged biopolymer is directly exposed to the blood stream and selectively buffers sodium ions. We hypothesize that the glycocalyx could interfere with endothelial sodium transport when extracellular sodium varies in the physiological range. Therefore, we modeled the endothelial cell as a pump-leak system measuring changes of intracellular sodium in cultured human endothelial cells. Experiments were performed under low/high extracellular sodium conditions before and after enzymatic eGC removal, and with inhibition of Na(+)/K(+)-ATPase and ENaC, respectively. Three major observations were made: (1) eGC removal by heparinase treatment facilitates sodium to enter/exit the endothelial cells. (2) The direction of net sodium movement across the endothelial plasma membrane depends on the concentration of extracellular sodium which regulates both the Na(+)/K(+)-ATPase and ENaC activity. (3) Removal of eGC and inhibition of sodium transport modify the electrical resistance of endothelial cells. We conclude that the eGC serves as a potential "firewall" preventing uncontrolled access of sodium to the pump-leak system of the endothelial cell. After eGC removal, sodium access to the system is facilitated. Thus the pump-leak system could be regulated by ambient sodium and control vascular permeability in pathophysiological conditions.

Topical timolol for small infantile hemangioma: a new therapy option.

The main characteristic of infantile hemangioma is that it grows rapidly after birth and mostly regresses spontaneously. It is a common practice for only a small part of the hemangioma to be treated, as they can be extremely disfiguring and destructive to normal tissue as well as possibly being life-threatening. Recent studies have discovered that the use of topical 0.5% timolol maleate gel is a new therapy option for infantile hemangioma. We have treated two children with hemangioma in our pediatric day center with topical timolol gel (Nyogel). We examined the children before the therapy and took photographs of the hemangioma. After a period of two weeks, pictures were re-taken and compared. A significant change in color from dark red to a lighter shade of red and partially even to skin color could be detected. The treatment outcome of our cases indicates that timolol gel is well-tolerated and effective for the therapy for infantile hemangioma. We further want to highlight the necessity to treat even small hemangiomas, as a reliable prediction of the possible extent of the expansion and involution does not exist.

Spectral Computed Tomography Angiography With a Gadolinium-based Contrast Agent: First Clinical Imaging Results in Cardiovascular Applications.

PURPOSE: Computed tomography angiography (CTA) requires IV application of iodine-based contrast agents. There are several medical conditions in which application is not advisable or even feasible, especially for elective examinations. Novel techniques such as monoenergetic reconstructions from dual-energy computed tomographic (CT) data have been shown to increase radiation attenuation of gadolinium (Gd)-based contrast agents in a phantom model. Therefore, the purpose of the present investigation was to evaluate the technical feasibility and image quality of clinical spectral CTA with a Gd-based contrast agent. MATERIALS AND METHODS: Eleven consecutive patients with common indications for thoracic CTA and contraindications for iodine-based contrast agents were examined using clinical routine doses (0.2 mmol/kg) of Gd-based contrast agent with spectral CT. Monoenergetic reconstructions of the spectral data set were computed. RESULTS: We performed 11 Gd-enhanced CTAs: 9 aortic angiographies, 1 coronary angiography, and 1 angiography of the pulmonary arteries. Image quality of the monoenergetic reconstructions with 40 keV (monoE40) was considered diagnostic by 2 experienced radiologists in each patient; the conventional CT reconstructions did not reach diagnostic image quality. MonoE40 reconstruction resulted in a substantial, ∼2-fold increase of intravascular Gd attenuation compared with the conventional images (P<0.0001). No relevant change of attenuation was observed for the myocardium or the skeletal muscle. CONCLUSIONS: With spectral CT and reconstruction of monoenergetic images with extrapolated 40 keV, Gd-based contrast agent thoracic angiography with clinical doses of Gd is technically feasible. Gd-based CTA seems a valuable alternative in patients with contraindications for iodine-based contrast media.

Accuracy of Calcium Scoring calculated from contrast-enhanced Coronary Computed Tomography Angiography using a dual-layer spectral CT: A comparison of Calcium Scoring from real and virtual non-contrast data.

PURPOSE: Modern non-invasive evaluation of Coronary Artery Disease (CAD) requires non-contrast low dose Computed Tomography (CT) imaging for determination of Calcium Scoring (CACS) and contrast-enhanced imaging for evaluation of vascular stenosis. Several methods for calculation of CACS from contrast-enhanced images have been proposed before. The main principle for that is generation of virtual non-contrast images by iodine subtraction from a contrast-enhanced spectral CT dataset. However, those techniques have some limitations: Dual-Source CT imaging can lead to increased radiation exposure, and switching of the tube voltage (rapid kVp switching) can be associated with slower rotation speed of the gantry and is thus prone to motion artefacts that are especially critical in cardiac imaging. Both techniques cannot simultaneously acquire spectral data. A novel technique to overcome these difficulties is spectral imaging with a dual-layer detector. After absorption of the lower energetic photons in the first layer, the second layer detects a hardened spectrum of the emitted radiation resulting in registration of two different energy spectra at the same time. The objective of the present investigation was to evaluate the accuracy of virtual non-contrast CACS computed from spectral data in comparison to standard non-contrast imaging. METHODS: We consecutively investigated 20 patients referred to Coronary Computed Tomography Angiography (CCTA) with suspicion of CAD using a Dual-Layer spectral CT system (IQon; Philips Healthcare, The Netherlands). CACS was calculated from both, real- and virtual non-contrast images by certified software for medical use. Correlation analyses for real- and virtual non-contrast images and agreement evaluation with Bland-Altman-Plots were performed. RESULTS: Mean patient age was 57.7 ± 14 years (n = 20). 13 patients (65%) were male. Inter-quartile-range of clinical CACS was 0-448, the mean was 334. Correlation of CACS from real- and virtual non-contrast images was very high (0.94); p < 0.0001. The slope was 2.3 indicating that values from virtual non-contrast images are approximately half of the results obtained from real non-contrast data. Visual analysis of Bland-Altman-Plot shows good accordance of both methods when results from virtual non-contrast data are multiplied by the slope of the logistic regression model (2.3). The acquired power of this results is 0.99. CONCLUSION: Determination of Calcium Score from contrast enhanced CCTA using spectral imaging with a dual-layer detector is feasible and shows good agreement with the conventional technique when a proportionality factor is applied. The observed difference between both methods is due to an underestimation of plaque volume, and-to an even greater extend -an underestimation of plaque density with the virtual non-contrast approach. Our data suggest that radiation exposure can be reduced through omitting additional native scans for patients referred to CCTA when using a dual-layer spectral system without the usual limitations of dual energy analysis.

The role of complementary medicine in a pediatric day center in Germany.

BACKGROUND: The role of complementary alternative medicine (CAM) in pediatrics has considerably increased in the last years. The knowledge about potential side effects and possible interactions with conventional drugs is still limited, and often pediatricians do not know whether their patients use CAM. This can be critical, as in order to diagnose and treat illnesses properly physicians need to know about the full extent of the self-administered therapy of their patients. Many studies have been conducted in other countries in order to assess the extent of CAM use and the types of substances that are consumed, but in Germany data in regard to pediatric interventions are lacking. We therefore developed a questionnaire to evaluate the frequency of CAM use among German pediatric patients. PATIENTS AND METHODS: 115 parents visiting the pediatric day center in Epe between September and November 2011 responded to the questionnaire. The survey contains questions concerning the prevalence of CAM use and data about socioeconomic factors. RESULTS: A total of 75.7% of all children enrolled in the study had already been treated with CAM by their parents, while only 43.6% of the parents knew that there can be interactions with CAM and prescribed drugs. In only half of the cases (50.6%) the pediatrician knew about the CAM usage of the child. CONCLUSION: The frequency of CAM usage among children is higher than anticipated. It is essential that pediatricians know about possible interactions with conventional medicine, and it lies in their responsibility to include the question about CAM usage in their standard protocols.

Parent satisfaction with a pediatric practice in Germany: a questionnaire-based study.

BACKGROUND: Parental satisfaction with a pediatric day center is essential for the medical treatment of children, since it is closely related to compliance. In order to ascertain factors which predict parental satisfaction as well as to discover possible weak points, we developed a questionnaire. METHODS: 127 parents visiting the pediatric day center from October to November 2010 were asked to respond to a questionnaire. The survey was given to them directly by the doctor after their visit and it provided the opportunity to determine subjective and soft factors in quality management, which is essential for a pediatric practice. The questionnaire consisted of 27 items divided into three scales. The scales were as follows: satisfaction concerning the infrastructure and organization, satisfaction concerning the communicative and empathic competence of the doctor as well as the other staff, and finally the results and the overall impression. Moreover, the survey asked the respondents for their comments on the pediatric day center and sociodemographic data were queried. RESULTS: A total of 67 parents (52,7%) responded to the survey. The mean parental satisfaction concerning infrastructure and organization achieved 3,61 (scale 1-very unsatisfied--through 4-very satisfied). The mean satisfaction with the expertise of the doctor and the staff was 3,56 and the overall satisfaction was 3,65. Ninety-one percent of the parents would visit the pediatric practice again and 84,2% would definitely recommend the practice to others. CONCLUSION: Surveys on parental satisfaction are essential for the success of a pediatric day center. Apart from the doctors abilities to interact with the parents, other factors, such as a short waiting period, a friendly and helpful staff, as well as appealing premises are essential for a high overall level of satisfaction.