Cascaded plane wave ultrasound for blood velocity vector imaging in the carotid artery

Cascaded dual-polarity waves (CDWs) imaging increases the signal-to-noise ratio (SNR) by transmitting trains of pulses with different polarity order, which are combined via decoding afterward. This potentially enables velocity vector imaging (VVI) in more challenging SNR conditions. However, the motion of blood in between the trains will influence the decoding process. In this work, the use of CDW for blood VVI is evaluated for the first time. Dual-angle, plane wave (PW) ultrasound, CDW-coded, and noncoded conventional PW (cPW), was acquired using a 7.8 MHz linear array at a pulse repetition frequency (PRF) of 8 kHz. CDW-channel data were decoded prior to beamforming and cross correlation-based compound speckle tracking for VVI. Simulations of single scatterer motion show a high dependence of amplitude gain on the velocity magnitude and direction for CDW-coded transmissions. Both simulations and experiments of parabolic flow show increased SNRs for CDW imaging. As a result, CDW outperforms cPW VVI in low SNR conditions, based on both bias and standard deviation (SD). Quantitative linear regression and qualitative analyses of simulated realistic carotid artery blood flow show a similar performance of CDW and cPW for high SNR (14 dB) conditions. However, reducing the SNR to 6 dB, results in a root-mean-squared error 2.7× larger for cPW versus CDW, and an R2 of 0.4 versus 0.9. Initial in vivo evaluation of a healthy carotid artery shows increased SNR and more reliable velocity estimates for CDW versus cPW. In conclusion, this work demonstrates that CDW imaging facilitates improved VVI of deeper located carotid arteries.</p

Osteoclast-like Cells in Early Zebrafish Embryos

Animal science

One in six physiotherapy practices in primary care offer musculoskeletal ultrasound - an explorative survey

BACKGROUND: The first aim of this research was to investigate the current prevalence of musculoskeletal ultrasound in Dutch physiotherapy practices. The second aim was to explore experiences of physiotherapists with musculoskeletal ultrasound in a primary care setting with patients presenting with shoulder complaints. METHODS: A random sample of 1000 owners of primary care physiotherapy practices was sent a questionnaire to investigate the prevalence of musculoskeletal ultrasound. A second questionnaire was sent to physiotherapists using musculoskeletal ultrasound to explore experiences with it in patients with shoulder complaints. RESULTS: The net response rate of the first questionnaire was 57.7%. In 18% of the physiotherapy practices musculoskeletal ultrasound was offered. Sixty-nine physiotherapists returned the second questionnaire. Physiotherapists indicated they most often used musculoskeletal ultrasound in patients with shoulder complaints, mainly for suspected tissue damage (83.7%), followed by making a diagnosis (63.3%) and for determining the choice of treatment (36.7%). Physiotherapists reported the biggest advantage was that they were better able to diagnose presenting shoulder complaints. The most frequently mentioned disadvantage of the use of musculoskeletal ultrasound was that assessment is difficult and that there is a risk that findings may not be sufficiently linked to history and physical examination. CONCLUSION: One in six physiotherapy practices in the Netherlands offer musculoskeletal ultrasound. It is mainly used for patients with shoulder complaints, with an emphasis on detecting tissue damage and as an aid for diagnosis. Physiotherapists trained to work with musculoskeletal ultrasound seem enthusiastic and are at the same time aware of it

Lage ciclosporinespiegel na kort rifampicinegebruik : immuunsuppressie kan langdurig tekortschieten

Cyclosporin is an immunosuppressive agent with a wide range of therapeutic uses. In transplant patients, it is used for the prevention of rejection and graft-versus-host reactions. The metabolism and bioavailability of cyclosporin can be significantly and persistently influenced through induction of CYP3A4 caused by the concomitant use of rifampicin. However, awareness of the need for the timely and frequent monitoring of cyclosporin levels during and especially after treatment with rifampicin has not fully been addressed. Here, we describe 3 patient cases concerning significant episodes of sub-therapeutic cyclosporin levels after short-term rifampicin therapy. Rifampicin was administered for three to five days and decreased cyclosporin levels were observed ± 7 days after the initiation of rifampicin, and continued during the following weeks even after the cessation of rifampicin therapy. Cyclosporin dosage-adjustments were made based on the cyclosporin blood levels and all 3 patients showed good therapeutic and clinical responses.Zelfs kortdurend gebruik van het antibioticum rifampicine kan de ciclosporineconcentratie in het bloed verlagen. Daarom moet de bloedspiegel van dit immunosuppressivum goed gemonitord worden bij patiënten die ook rifampicine krijgen, ook als de patiënt al gestopt is met het middel. Om afstoting van transplantaten of graft-versus-hostreacties te voorkómen, is het vaak nodig de ciclosporinedosering aan te passen

Ventricular septation and outflow tract development in crocodilians result in two aortas with bicuspid semilunar valves

Background: The outflow tract of crocodilians resembles that of birds and mammals as ventricular septation is complete. The arterial anatomy, however, presents with a pulmonary trunk originating from the right ventricular cavum, and two aortas originating from either the right or left ventricular cavity. Mixing of blood in crocodilians cannot occur at the ventricular level as in other reptiles but instead takes place at the aortic root level by a shunt, the foramen of Panizza, the opening of which is guarded by two facing semilunar leaflets of both bicuspid aortic valves. Methods: Developmental stages of Alligator mississipiensis, Crocodilus niloticus and Caiman latirostris were studied histologically. Results and Conclusions: The outflow tract septation complex can be divided into two components. The aorto-pulmonary septum divides the pulmonary trunk from both aortas, whereas the interaortic septum divides the systemic from the visceral aorta. Neural crest cells are most likely involved in the formation of both components. Remodeling of the endocardial cushions and both septa results in the formation of bicuspid valves in all three arterial trunks. The foramen of Panizza originates intracardially as a channel in the septal endocardial cushion.Cardiolog

Angular Conditions,Relations between Breit and Light-Front Frames, and Subleading Power Corrections

We analyze the current matrix elements in the general collinear (Breit) frames and find the relation between the ordinary (or canonical) helicity amplitudes and the light-front helicity amplitudes. Using the conservation of angular momentum, we derive a general angular condition which should be satisfied by the light-front helicity amplitudes for any spin system. In addition, we obtain the light-front parity and time-reversal relations for the light-front helicity amplitudes. Applying these relations to the spin-1 form factor analysis, we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light-front time-reversal condition. We make some comments on the consequences of the angular condition for the analysis of the high-$Q^2$ deuteron electromagnetic form factors, and we further apply the general angular condition to the electromagnetic transition between spin-1/2 and spin-3/2 systems and find a relation useful for the analysis of the N-$\Delta$ transition form factors. We also discuss the scaling law and the subleading power corrections in the Breit and light-front frames.Comment: 24 pages,2 figure