Standardized measurement of coronary inflammation using cardiovascular computed tomography: integration in clinical care as a prognostic medical device

Aims: Coronary computed tomography angiography (CCTA) is a first-line modality in the investigation of suspected coronary artery disease (CAD). Mapping of perivascular fat attenuation index (FAI) on routine CCTA enables the non-invasive detection of coronary artery inflammation by quantifying spatial changes in perivascular fat composition. We now report the performance of a new medical device, CaRi-Heart®, which integrates standardized FAI mapping together with clinical risk factors and plaque metrics to provide individualized cardiovascular risk prediction. Methods and results: The study included 3912 consecutive patients undergoing CCTA as part of clinical care in the USA (n = 2040) and Europe (n = 1872). These cohorts were used to generate age-specific nomograms and percentile curves as reference maps for the standardized interpretation of FAI. The first output of CaRi-Heart® is the FAI-Score of each coronary artery, which provides a measure of coronary inflammation adjusted for technical, biological, and anatomical characteristics. FAI-Score is then incorporated into a risk prediction algorithm together with clinical risk factors and CCTA-derived coronary plaque metrics to generate the CaRi-Heart® Risk that predicts the likelihood of a fatal cardiac event at 8 years. CaRi-Heart® Risk was trained in the US population and its performance was validated externally in the European population. It improved risk discrimination over a clinical risk factor-based model [Δ(C-statistic) of 0.085, P = 0.01 in the US Cohort and 0.149, P < 0.001 in the European cohort] and had a consistent net clinical benefit on decision curve analysis above a baseline traditional risk factor-based model across the spectrum of cardiac risk. Conclusion: Mapping of perivascular FAI on CCTA enables the non-invasive detection of coronary artery inflammation by quantifying spatial changes in perivascular fat composition. We now report the performance of a new medical device, CaRi-Heart®, which allows standardized measurement of coronary inflammation by calculating the FAI-Score of each coronary artery. The CaRi-Heart® device provides a reliable prediction of the patient's absolute risk for a fatal cardiac event by incorporating traditional cardiovascular risk factors along with comprehensive CCTA coronary plaque and perivascular adipose tissue phenotyping. This integration advances the prognostic utility of CCTA for individual patients and paves the way for its use as a dual diagnostic and prognostic tool among patients referred for CCTA

Technical aspects of CT imaging of the spine

This review article discusses technical aspects of computed tomography (CT) imaging of the spine. Patient positioning, and its influence on image quality and movement artefact, is discussed. Particular emphasis is placed on the choice of scan parameters and their relation to image quality and radiation burden to the patient. Strategies to reduce radiation burden and artefact from metal implants are outlined. Data acquisition, processing, image display and steps to reduce artefact are reviewed. CT imaging of the spine is put into context with other imaging modalities for specific clinical indications or problems. This review aims to review underlying principles for image acquisition and to provide a rough guide for clinical problems without being prescriptive. Individual practice will always vary and reflect differences in local experience, technical provisions and clinical requirements

Imaging biomarkers for cardiovascular risk prediction with CT techniques

Title: Imaging biomarkers for cardiovascular risk prediction with CT techniques Background: Coronary plaque formation, progression and rupture are still the major cause for myocardial infarction. Although many ways for the identification of high-risk plaques have been developed and evaluated over the last decade, they are still not able to forecast the development and rupture of an individual plaque precisely. With the increase of new techniques such as radiomics and the fat attenuation index (FAI), new risk stratification techniques for coronary plaques could be established. Methods: The first part developed an automated coronary plaque segmentation tool for calcified and non-calcified plaque components. The second part compared statistical versus radiomics-based automated plaque classification approaches. These two parts aimed to facilitate an automated coronary plaque analysis on future big cohorts. In the last part, FAI around plaques (pFAI) was analysed and differences between individual coronary plaque categories were compared. Results: After showing excellent results on intra- and interobserver analysis for the manual segmented dataset, a model for calcified plaque components achieved very good results, even outperforming metrics from the interobserver analysis. The radiomics-based approach for non-calcified plaque detection proved the feasibility of this method by showing good initial results. While an automated plaque classification based on two first-order statistical values has already worked well, radiomics were able to even outperform this in terms of accuracy and diversification of plaque types. Measured pFAI revealed significant differences between individual plaque classes based on their degree of calcification. Discussion: Although the size of the manual labeled and segmented datasets was limited, meaningful models for an automated coronary plaque segmentation and classification were developed. Further, it was shown that FAI around different plaque types provides additional information on their inflammatory status and, therefore, eventually on their individual risk, which has to be investigated on plaque-specific outcome data in the future.</p

Reactions with oleum under harsh conditions : characterization of the unique [M(S2O7)3]2- ions (M=Si, Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag)

The reactions of group 14 tetrachlorides MCl4 (M=Si, Ge, Sn) with oleum (65&thinsp;% SO3) at elevated temperatures lead to the unique complex ions [M(S2O7)3]2&minus;, which show the central M atoms in coordination with three chelating S2O72&minus; groups. The mean distances M[BOND]O within the anions increase from 175.6(2)&ndash;177.5(2) pm (M=Si) to 186.4(4)&ndash;187.7(4) pm (M=Ge) to 201.9(2)&ndash;203.5(2) pm (M=Sn). These distances are reproduced well by DFT calculations. The same calculations show an increasing positive charge for the central M atom in the row Si, Ge, Sn, which can be interpreted as the decreasing covalency of the M[BOND]O bonds. For the silicon compound (NH4)2[Si(S2O7)3], 29Si solid-state NMR measurements have been performed, with the results showing a signal at &minus;215.5 ppm for (NH4)2[Si(S2O7)3], which is in very good agreement with theoretical estimations. In addition, the vibrational modes within the [MO6] skeleton have been monitored by Raman spectroscopy for selected examples, and are well reproduced by theory. The charge balance for the [M(S2O7)3]2&minus; ions is achieved by monovalent A+ counter ions (A=NH4, Ag), which are implemented in the syntheses in the form of their sulfates. The sizes of the A+ ions, that is, their coordination requirements, cause the crystallographic differences in the crystal structures, although the complex [M(S2O7)3]2&minus; ions remain essentially unaffected with the different A+ ions. Furthermore, the nature of the A+ ions influences the thermal behavior of the compounds, which has been monitored for selected examples by thermogravimetric differential thermal analysis (DTA/TG) and XRD measurements

Flexible NO2-Functionalized N-Heterocyclic Carbene Monolayers on Au(111) Surface

Invited for the cover of this issue are Elad Gross, F. Dean Toste, and co-workers at The Hebrew University and UC Berkeley. The image depicts the flexible anchoring geometry of addressable carbene molecules on Au surface, which upon exposure to reducing conditions changed their orientation from a standing into a flat-lying position. Read the full text of the article at 10.1002/chem.201903434