A large aperture row column addressed probe for in vivo 4D ultrafast doppler ultrasound imaging.

Four-dimensional (4D) Ultrafast ultrasound imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D as well as anatomical, mechanical or functional information. In 4D Ultrafast imaging, coherent compounding of tilted planes waves emitted by a 2D matrix array were used to image the medium at high volume rate. 4D ultrafast imaging, however, requires a high channel count (>1000) to drive those probes. Alternative approaches have been proposed and investigated to efficiently reduce the density of elements, such as sparse or under-sampled arrays while maintaining a decent image quality and high volume rate. The row-columns configuration presents the advantage of keeping a large active surface with a low amount of elements and a simple geometry. In this study, we investigate the row and column addressed (RCA) approach with the orthogonal plane wave (OPW) compounding strategy using real hardware limitations. We designed and built a large 7 MHz 128 + 128 probe dedicated to vascular imaging and connected to a 256-channel scanner to implement the OPW imaging scheme. Using this strategy, we demonstrate that 4D ultrafast Power Doppler imaging of a large volume of [Formula: see text] up to [Formula: see text] depth, both in vitro on flow phantoms and in vivo on the carotid artery of a healthy volunteer at a volume rate of 834 Hz.

[Temporal meaning of suffering]. / Le sens temporel de la souffrance.

If we had to find a few simple words to express what a suffering human being experiences, no matter what ills are causing the suffering and no matter what circumstances underlie the ills themselves, we could unmistakably say that it is the experience of not being able to go on like this. Suffering can be described, in this same sense, as an alteration in temporality. However, describing suffering as such only makes sense if we already have a conception of normal temporality. Yet for this, philosophical tradition offers not one but four competing conceptions. In the present article, we begin by briefly presenting these different conceptions. We then show how each one sheds light, by way of contrast, on a phenomenon whose meaning thus appears to be essentially negative. But does this phenomenon have a negative meaning only? Doesn't it correspond as much to a transformation as an alteration of temporality? This is what we will strive to establish in the third part of the article by relating suffering to hope, in a paradoxical sense of the term. Of the four conceptions of time likely to shed a contrasting light on the upheavals that suffering introduces into our life experience, the one described by Aristotle in Physics is historically the first. In particular, the notion of succession originates therein. But this conception does not account for what makes time the unit of a past, a present, and a future. In Book XI of Confessions, St. Augustine situated this unit not in nature but in the human mind. Hence, his definition of time as a distension of the soul and the necessary division into physical time and psychic time it entails. Husserl's Lessons on the phenomenology of the consciousness of internal time lend credit to this division, but they illuminate only the internal constitution of the "present", which is at the heart of the psychological conception of time. In Being and Time, Heidegger breaks away from this long-standing tradition; in his view, physical time and psychic also time take root in the temporality of "planning", understood to be a general form of openness to the world. But in our minds, "being" means more than "being in the world"; it also means, and by that very token, "being for death". Anguish is the fundamental experience that brings out this structural identity. As such, it lies at the core of Heidegger's conception of temporality. Nonetheless, is death the ultimate truth of time? This is what Paul Ricoeur denies in establishing an internal relationship between time and narration, for narration not only produces a synthesis of time, it also allows us to assume a future which, granted, presupposes death but does not remain its captive. This supports a fourth conception of time, that summarized by the notion of "narrated time". Narrative resources do not; however, cancel the multiple alterations that suffering introduces into temporality, which, by contrast, can be reduced - as we show in the second part of the article in reference to the preceding conceptions - to four descriptive features: dechronologization, reduction of the present to the instant, breakdown of the plan, and disintegration of the narrative. They explain why, in the presence of suffering, life seems more impossible than death. But at the same time, it leaves us with an enigma: Why doesn't the suffering human being always choose death? This enigma, above all, is the enigma of melancholic suffering. Hence, the privileged place given to melancholy in the last part of the article, where psychiatry encounters philosophy and justifies some distinctions that philosophy alone would not have dared make. A case in point is Minkowski's distinction, in Lived Time, between "activity" and "waiting", and also holds for our own distinction, following Minkowski, between planning time and hoping time, where hoping is to be taken in the deeper sense than implied by the common opposition between "hope" and "despair".