Material differentiation in forensic radiology with single-source dual-energy computed tomography

The goal of this study was to investigate the use of dual-energy computed tomography (CT) in differentiating frequently encountered foreign material on CT images using a standard single-source CT scanner. We scanned 20 different, forensically relevant materials at two X-Ray energy levels (80 and 130 kVp) on CT. CT values were measured in each object at both energy levels. Intraclass correlation coefficient (ICC) was used to determine intra-reader reliability. Analysis of variance (ANOVA) was performed to assess significance levels between X-Ray attenuation at 80 and 130 kVp. T test was used to investigate significance levels between mean HU values of individual object pairings at single energy levels of 80 and 130 kVp, respectively. ANOVA revealed that the difference in attenuation between beam energies of 80 kVp compared to 130 kVp was statistically significant (p < 0.005) for all materials except brass and lead. ICC was excellent at 80 kVp (0.999, p < 0.001) and at 130 kVp (0.998, p < 0.001). T test showed that using single energy levels of 80 and 130 kVp respectively 181/190 objects pairs could be differentiated from one another based on HU measurements. Using the combined information from both energy levels, 189/190 object pairs could be differentiated. Scanning with different energy levels is a simple way to apply dual-energy technique on a regular single-energy CT and improves the ability to differentiate foreign bodies with CT, based on their attenuation values.     

Membrane‐bound stem cell factor is the major but not only driver of fibroblast‐induced murine skin mast cell differentiation

The maintenance and modulation of cutaneous mast cell (MC) numbers is held to be important for skin immune responses to allergens and pathogens. The increase in MC numbers in the skin is achieved by proliferation and the differentiation of precursor to mature MCs. Fibroblast‐derived SCF is thought to be the major skin MC growth factor and it potently induces MC proliferation. The mechanisms of fibroblast‐induced skin MC differentiation, including the role of SCF, however, remain insufficiently characterized and understood. Using cocultures of immature murine MCs and fibroblasts, we found that the adhesion of immature MCs to fibroblasts via VCAM‐1 and α₄β₇ integrin is very important for subsequent differentiation, which is driven by fibroblast membrane‐bound SCF and additional fibroblast‐derived membrane‐bound signals. Thus, our results show that fibroblast‐induced MC differentiation is induced by direct cell–cell contact and involves both Kit‐dependent and Kit‐independent pathways. Our findings add to the understanding of how immature mast cells mature in murine skin and encourage further analyses of the underlying mechanisms, which may result in novel targets for the modulation of skin mast cell driven diseases.     

Diffusion parameter mapping with the combined intravoxel incoherent motion and kurtosis model using artificial neural networks at 3 T

Artificial neural networks (ANNs) were used for voxel‐wise parameter estimation with the combined intravoxel incoherent motion (IVIM) and kurtosis model facilitating robust diffusion parameter mapping in the human brain. The proposed ANN approach was compared with conventional least‐squares regression (LSR) and state‐of‐the‐art multi‐step fitting (LSR‐MS) in Monte‐Carlo simulations and in vivo in terms of estimation accuracy and precision, number of outliers and sensitivity in the distinction between grey (GM) and white (WM) matter. Both the proposed ANN approach and LSR‐MS yielded visually increased parameter map quality. Estimations of all parameters (perfusion fraction f, diffusion coefficient D, pseudo‐diffusion coefficient D*, kurtosis K) were in good agreement with the literature using ANN, whereas LSR‐MS resulted in D* overestimation and LSR yielded increased values for f and D*, as well as decreased values for K. Using ANN, outliers were reduced for the parameters f (ANN, 1%; LSR‐MS, 19%; LSR, 8%), D* (ANN, 21%; LSR‐MS, 25%; LSR, 23%) and K (ANN, 0%; LSR‐MS, 0%; LSR, 15%). Moreover, ANN enabled significant distinction between GM and WM based on all parameters, whereas LSR facilitated this distinction only based on D and LSR‐MS on f, D and K. Overall, the proposed ANN approach was found to be superior to conventional LSR, posing a powerful alternative to the state‐of‐the‐art method LSR‐MS with several advantages in the estimation of IVIM–kurtosis parameters, which might facilitate increased applicability of enhanced diffusion models at clinical scan times.     

Early and sustained haemodynamic improvement with levosimendan compared to intraaortic balloon counterpulsation (IABP) in cardiogenic shock complicating acute myocardial infarction

OBJECTIVE: To investigate the haemodynamic effects of levosimendan in patients with cardiogenic shock (CS) complicating acute myocardial infarction in comparison to the effects of intra-aortic balloon counterpulsation (IABP). METHODS: 10 patients with intractable CS under standard therapy (including the use of PCI, inotropes, and vasopressors) received i.v. infusion of levosimendan (bolus 12 microg/kg i.v., followed by continuous infusion 0.1 microg/kg/min for 24 h). Haemodynamic effects were compared to the effects of IABP-placement added to standard care in 12 patients with CS. RESULTS: Within 24 h, both levosimendan and IABP produced a significant increase in cardiac index (CI) and cardiac power index and a decrease in systemic vascular resistance (SVR) (CI [l/min/m2] baseline 1.97+/-0.15, at 24 h 2.82+/-0.22 for levosimendan; baseline 1.98+/-0.17, at 24 h 2.66+/-0.08 for IABP; SVR [dyn*s*cm-5] baseline 1353+/-106, at 24 h 846+/-69 for levosimendan; baseline 1311+/-214, at 24 h 853+/-63 for IABP, respectively). After 3 h of treatment, CI and SVR had significantly improved in patients treated with levosimendan but not in the IABP-group (CI [l/min/m2] at 3 h 2.72+/-0.28 (+38%) for levosimendan versus 2.18+/-0.15 (+10%) for IABP). CONCLUSION: Infusion of levosimendan in acute CS results in early and sustained haemodynamic improvement. Short-term haemodynamic effects compare favourably with those seen after invasive IABP placement.     

Refining the Baveno VI elastography criteria for the definition of compensated advanced chronic liver disease

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