Screening cardiovascular patients for aortic aneurysms (SCAN) - high prevalence of abdominal aortic aneurysms in coronary heart disease patients requiring intervention.

Background: Since the prevalence of abdominal aortic aneurysms (AAA) in Europe has declined to about 2.5%, general screening programs of elderly men are being called into question. On the other hand, other vascular diseases (e.g. coronary heart disease, CHD) are associated with a higher prevalence of AAA. This might have an impact on future targeted AAA screening programs. This study aimed to reevaluate the current prevalence of AAA in male patients with CHD, in order to assess whether CHD patients should be offered a targeted AAA ultrasound screening program. Patients and methods: The SCAN (Screening Cardiovascular Patients for Aortic Aneurysms) study prospectively evaluated the AAA prevalence in 1000 consecutive male CHD patients (70.1 ± 11.2 years) requiring any coronary intervention at an university hospital. All patients received transverse and longitudinal ultrasound scans of the abdominal aorta. Aortic diameter was assessed using the outer-to-outer measurement-technique. Primary endpoint was the prevalence of AAA. Secondary outcomes included stratification in 1-, 2-, or 3-vessel CHD. Results: AAA was detected in 85 patients (median diameter 38 mm, range 30-80 mm), corresponding to an overall prevalence of 8.5%. AAA prevalence was significantly associated with CHD severity: 5.6% in 1-vessel, 7.1% in 2-vessel, and 10.8% in 3-vessel CHD (P = 0.037). The multivariable analysis showed, that age per 10 years increase (OR 1.5, 95% CI 1.2-1.9, P = 0.001) and hyperlipidemia (OR 2.2, 95% CI 1.3-3.8, P = 0.003) were significantly associated with an AAA. The likelihood to be diagnosed with an AAA was significantly lower in non-smokers (OR 0.24, 95% CI, P < 0.001). Conclusions: This study confirms that CHD requiring any type of coronary intervention is strongly associated with AAA in male patients. AAA prevalence increases with CHD severity. Since the AAA prevalence is still significantly higher than in the general population, targeted ultrasound screening should be considered for all CHD patients.

Clinical implications of the incidental finding of a free-floating thrombus in the internal carotid artery.

We present an 81-year old male in whom a routine carotid artery ultrasonographic follow-up examination incidentally revealed a large, free-floating thrombus (FFT) of the right internal carotid artery. This case focuses on the clinical decision-making regarding FFTs, which constitute a rare condition lacking a diagnostic gold standard with few available data concerning optimum treatment and natural course-in particular regarding patients in whom FFT is an incidental finding. We were able to demonstrate the accuracy of carotid artery ultrasonography in the detection as well as follow-up of FFT. Of clinical interest is furtherly a possible partial disappearance by spontaneous re-adhesion or resolution of the FFT.

Optoacoustic biomarkers of lipids, hemorrhage and inflammation in carotid atherosclerosis.

Imaging plays a critical role in exploring the pathophysiology and enabling the diagnostics and therapy assessment in carotid artery disease. Ultrasonography, computed tomography, magnetic resonance imaging and nuclear medicine techniques have been used to extract of known characteristics of plaque vulnerability, such as inflammation, intraplaque hemorrhage and high lipid content. Despite the plethora of available techniques, there is still a need for new modalities to better characterize the plaque and provide novel biomarkers that might help to detect the vulnerable plaque early enough and before a stroke occurs. Optoacoustics, by providing a multiscale characterization of the morphology and pathophysiology of the plaque could offer such an option. By visualizing endogenous (e.g., hemoglobin, lipids) and exogenous (e.g., injected dyes) chromophores, optoacoustic technologies have shown great capability in imaging lipids, hemoglobin and inflammation in different applications and settings. Herein, we provide an overview of the main optoacoustic systems and scales of detail that enable imaging of carotid plaques in vitro, in small animals and humans. Finally, we discuss the limitations of this novel set of techniques while investigating their potential to enable a deeper understanding of carotid plaque pathophysiology and possibly improve the diagnostics in future patients with carotid artery disease.

Dermal features derived from optoacoustic tomograms via machine learning correlate microangiopathy phenotypes with diabetes stage.

Skin microangiopathy has been associated with diabetes. Here we show that skin-microangiopathy phenotypes in humans can be correlated with diabetes stage via morphophysiological cutaneous features extracted from raster-scan optoacoustic mesoscopy (RSOM) images of skin on the leg. We obtained 199 RSOM images from 115 participants (40 healthy and 75 with diabetes), and used machine learning to segment skin layers and microvasculature to identify clinically explainable features pertaining to different depths and scales of detail that provided the highest predictive power. Features in the dermal layer at the scale of detail of 0.1-1 mm (such as the number of junction-to-junction branches) were highly sensitive to diabetes stage. A 'microangiopathy score' compiling the 32 most-relevant features predicted the presence of diabetes with an area under the receiver operating characteristic curve of 0.84. The analysis of morphophysiological cutaneous features via RSOM may allow for the discovery of diabetes biomarkers in the skin and for the monitoring of diabetes status.

Wet Imprinting of Channel-Type Superstructures in Nanostructured Titania Thin Films at Low Temperatures for Hybrid Solar Cells.

Hierarchically structured titania films, exhibiting interconnected foam-like nanostructures and large-scale channel-type superstructures, were achieved in an energy-saving way at low temperatures by a polymer template-assisted sol-gel synthesis in combination with a wet-imprinting process. The surface morphology was probed with scanning electron microscopy and atomic force microscopy, whereas the inner morphology was characterized with grazing incidence small-angle X-ray scattering measurements. Compared to the initial hybrid films, the titania films showed reduced structure sizes caused by removal of the polymer template. UV/Vis measurements showed an additional light-scattering effect at various angles of light incidence in the hierarchically structured titania films, which resulted in higher light absorption in the wet-imprinted active layer. To give proof of viability, the titania films were evaluated as photoanodes for dye-free hybrid solar cells. The dye-free layout allowed for low-cost fabrication, avoided problems related to dye bleaching, and was a more environmentally friendly alternative to using dyes. Under different angles of light incidence, the enhancement in the short-circuit current density was in good agreement with the improvement in light absorption in the superstructured active layer, demonstrating a positive impact of the superstructures on the photovoltaic performance of hybrid solar cells.

Codependence between Crystalline and Photovoltage Evolutions in P3HT:PCBM Solar Cells Probed with in-Operando GIWAXS.

We address the correlation between the crystalline state of photoactive materials in a model organic solar cell based on poly(3-hexylthiophene-2,5-diyl):phenyl-C60-butyric acid methyl ester (P3HT:PCBM) and the photovoltage in an in-operando investigation. I-V curves are simultaneously measured together with grazing incidence wide-angle X-ray scattering probing the crystalline state of the device active layer as a function of the operation time. The results show a high degree of correlation between open-circuit voltage VOC and the crystalline state of P3HT.

Effect of Blend Composition and Additives on the Morphology of PCPDTBT:PC71BM Thin Films for Organic Photovoltaics.

The use of solvent additives in the fabrication of bulk heterojunction polymer:fullerene solar cells allows to boost efficiencies in several low bandgap polymeric systems. It is known that solvent additives tune the nanometer scale morphology of the bulk heterojunction. The full mechanism of efficiency improvement is, however, not completely understood. In this work, we investigate the influences of blend composition and the addition of 3 vol % 1,8-octanedithiol (ODT) as solvent additive on polymer crystallization and both, vertical and lateral morphologies of poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] and [6,6]-phenyl C71-butyric acid methyl ester (PCPDTBT:PC71BM) blend thin films processed from chlorobenzene-based solutions. The nanoscale morphology is probed with grazing incidence small- and wide-angle X-ray scattering as well as X-ray reflectivity and complemented with UV/vis spectroscopy. In PCPDTBT:PC71BM films the use of ODT is found to lower the solubility of fullerene in the polymer matrix and to promote polymer crystallization, both vertical and lateral microphase separation with morphological coarsening, and formation of a fullerene-rich topping layer. The enhanced photovoltaic performance is explained by these findings.

A Closer Look into Two-Step Perovskite Conversion with X-ray Scattering.

Recently, hybrid perovskites have gathered much interest as alternative materials for the fabrication of highly efficient and cost-competitive solar cells; however, many questions regarding perovskite crystal formation and deposition methods remain. Here we have applied a two-step protocol where a crystalline PbI2 precursor film is converted to MAPbI3-xClx perovskite upon immersion in a mixed solution of methylammonium iodide and methylammonium chloride. We have investigated both films with grazing incidence small-angle X-ray scattering to probe the inner film morphology. Our results demonstrate a strong link between lateral crystal sizes in the films before and after conversion, which we attribute to laterally confined crystal growth. Additionally, we observe an accumulation of smaller grains within the bulk in contrast with the surface. Thus, our results help to elucidate the crystallization process of perovskite films deposited via a two-step technique that is crucial for controlled film formation, improved reproducibility, and high photovoltaic performance.

A direct evidence of morphological degradation on a nanometer scale in polymer solar cells.

In situ measurement of a polymer solar cell using micro grazing incidence small angle X-ray scattering (µGISAXS) and current-voltage tracking is demonstrated. While measuring electric characteristics under illumination, morphological changes are probed by µGISAXS. The X-ray beam (green) impinges on the photo active layer with a shallow angle and scatters on a 2d detector. Degradation is explained by the ongoing nanomorphological changes observed.