My advice was evidence based – Noakes

The Health Professions Council of South Africa this February closed its case against University of Cape Town emeritus professor Tim Noakes on a charge of unprofessional conduct and will resume with cross-examination of the controversial A-rated scientist on 17 October this year

The "quasi-stable" lipid shelled microbubble in response to consecutive ultrasound pulses

Controlled microbubble stability upon exposure to consecutive ultrasound exposures is important for increased sensitivity in contrast enhanced ultrasound diagnostics and manipulation for localised drug release. An ultra high-speed camera operating at 13 × 10 6 frames per second is used to show that a physical instability in the encapsulating lipid shell can be promoted by ultrasound, causing loss of shell material that depends on the characteristics of the microbubble motion. This leads to well characterized disruption, and microbubbles follow an irreversible trajectory through the resonance peak, causing the evolution of specific microbubble spectral signatures. © 2012 American Institute of Physics

Static response of coated microbubbles:Modeling simulations and parameter estimation

AbstractThe mechanical response of contrast agent microbubbles subject to a static load was investigated in force-deformation curves. Asymptotic relations are fitted with experimental AFM measurements of polymeric microbubbles available in the literature. The elastic modulus and shell thickness are estimated based on the transition from the classical linear (Reissner) to the nonlinear (Pogorelov) regime. The estimated value of the elastic modulus is in the order of GPa and the shell thickness in the order of nm, in good agreement with independent estimates. Numerical simulations recover the above transition and identify a third regime, dominated by the compressibility of the enclosed gas

Differentiation of Vascular Characteristics Using Contrast-Enhanced Ultrasound Imaging

Ultrasound contrast imaging has been used to assess tumour growth and regression by assessing the flow through the macro- and micro-vasculature. Our aim was to differentiate the blood kinetics of vessels such as veins, arteries and microvasculature within the limits of the spatial resolution of contrast-enhanced ultrasound imaging. The highly vascularised ovine ovary was used as a biological model. Perfusion of the ovary with SonoVue was recorded with a Philips iU22 scanner in contrast imaging mode. One ewe was treated with prostaglandin to induce vascular regression. Time-intensity curves (TIC) for different regions of interest were obtained, a lognormal model was fitted and flow parameters calculated. Parametric maps of the whole imaging plane were generated for 2 × 2 pixel regions of interest. Further analysis of TICs from selected locations helped specify parameters associated with differentiation into four categories of vessels (arteries, veins, medium-sized vessels and micro-vessels). Time-dependent parameters were associated with large veins, whereas intensity-dependent parameters were associated with large arteries. Further development may enable automation of the technique as an efficient way of monitoring vessel distributions in a clinical setting using currently available scanners.Agência financiadora Medical Research Council UK (MRC) 30800896 Science & Technology Facilities Council (STFC) ST/M007804/1 British Heart Foundation PG/10/021/28254 Life Sciences Discovery Fund 3292512 United States Department of Defense CA160415/PRCRPinfo:eu-repo/semantics/publishedVersio

Improved microbubble (MB) Localisation Using Particle Detecting algorithm:Evaluation of Algorithm Performance for Different Beamforming Methods

International audienceThe performance of image analysis techniques (particle detection) on contrast enhanced ultrasound (CEUS) images could be enhanced by using it in combination with the right beamformer (BF). The current study investigates the best performing combination of a particle detecting algorithm (Kanoulas et al. 2019) with four beamformers (BFs), classical and adaptive. In a series of in silico experiments, adjacent MBs are placed in distances comparable to the lateral resolution limit, the CEUS images of the MBs were simulated in FieldII, and finally beamformed with the four methods. The images were processed with the MB detection algorithm and the results were evaluated by the true detections (TD), missed MBs, spurious detections, and localisation uncertainty (LU). For the smallest distances all methods deteriorate but the MV methods provided 4-12% more TD. For the intermediate distances the TD were comparable for all BFs but the adaptive methods provided lower LU. When a set of evaluation metrics is used, the adaptive methods provide marginally but systematically improved results which suggests that, under the appropriate imaging conditions, they could be used to enhance vessel mapping